Network Working Group A. Bierman
Internet-Draft YumaWorks
Intended status: Standards Track M. Bjorklund
Expires: April 1, 2017 Tail-f Systems
K. Watsen
Juniper Networks
September 28, 2016
RESTCONF Protocol
draft-ietf-netconf-restconf-17
Abstract
This document describes an HTTP-based protocol that provides a
programmatic interface for accessing data defined in YANG, using the
datastore concepts defined in NETCONF.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on April 1, 2017.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.1. NETCONF . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.2. HTTP . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.3. YANG . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.4. NETCONF Notifications . . . . . . . . . . . . . . . . 7
1.1.5. Terms . . . . . . . . . . . . . . . . . . . . . . . . 8
1.1.6. URI Template and Examples . . . . . . . . . . . . . . 10
1.1.7. Tree Diagrams . . . . . . . . . . . . . . . . . . . . 10
1.2. Subset of NETCONF Functionality . . . . . . . . . . . . . 11
1.3. Data Model Driven API . . . . . . . . . . . . . . . . . . 11
1.4. Coexistence with NETCONF . . . . . . . . . . . . . . . . 12
1.5. RESTCONF Extensibility . . . . . . . . . . . . . . . . . 13
2. Transport Protocol Requirements . . . . . . . . . . . . . . . 15
2.1. Integrity and Confidentiality . . . . . . . . . . . . . . 15
2.2. HTTPS with X.509v3 Certificates . . . . . . . . . . . . . 15
2.3. Certificate Validation . . . . . . . . . . . . . . . . . 15
2.4. Authenticated Server Identity . . . . . . . . . . . . . . 15
2.5. Authenticated Client Identity . . . . . . . . . . . . . . 16
3. Resources . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1. Root Resource Discovery . . . . . . . . . . . . . . . . . 17
3.2. RESTCONF Media Types . . . . . . . . . . . . . . . . . . 19
3.3. API Resource . . . . . . . . . . . . . . . . . . . . . . 19
3.3.1. {+restconf}/data . . . . . . . . . . . . . . . . . . 20
3.3.2. {+restconf}/operations . . . . . . . . . . . . . . . 20
3.3.3. {+restconf}/yang-library-version . . . . . . . . . . 21
3.4. Datastore Resource . . . . . . . . . . . . . . . . . . . 21
3.4.1. Edit Collision Prevention . . . . . . . . . . . . . . 22
3.5. Data Resource . . . . . . . . . . . . . . . . . . . . . . 23
3.5.1. Timestamp . . . . . . . . . . . . . . . . . . . . . . 24
3.5.2. Entity-Tag . . . . . . . . . . . . . . . . . . . . . 24
3.5.3. Encoding Data Resource Identifiers in the Request URI 24
3.5.4. Default Handling . . . . . . . . . . . . . . . . . . 28
3.6. Operation Resource . . . . . . . . . . . . . . . . . . . 29
3.6.1. Encoding Operation Resource Input Parameters . . . . 30
3.6.2. Encoding Operation Resource Output Parameters . . . . 34
3.6.3. Encoding Operation Resource Errors . . . . . . . . . 36
3.7. Schema Resource . . . . . . . . . . . . . . . . . . . . . 37
3.8. Event Stream Resource . . . . . . . . . . . . . . . . . . 38
3.9. Errors YANG Data Template . . . . . . . . . . . . . . . . 39
4. RESTCONF Methods . . . . . . . . . . . . . . . . . . . . . . 39
4.1. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.2. HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . 40
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4.3. GET . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.4. POST . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.4.1. Create Resource Mode . . . . . . . . . . . . . . . . 42
4.4.2. Invoke Operation Mode . . . . . . . . . . . . . . . . 44
4.5. PUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.6. PATCH . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.6.1. Plain Patch . . . . . . . . . . . . . . . . . . . . . 47
4.7. DELETE . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.8. Query Parameters . . . . . . . . . . . . . . . . . . . . 49
4.8.1. The "content" Query Parameter . . . . . . . . . . . . 50
4.8.2. The "depth" Query Parameter . . . . . . . . . . . . . 51
4.8.3. The "fields" Query Parameter . . . . . . . . . . . . 51
4.8.4. The "filter" Query Parameter . . . . . . . . . . . . 52
4.8.5. The "insert" Query Parameter . . . . . . . . . . . . 53
4.8.6. The "point" Query Parameter . . . . . . . . . . . . . 54
4.8.7. The "start-time" Query Parameter . . . . . . . . . . 54
4.8.8. The "stop-time" Query Parameter . . . . . . . . . . . 55
4.8.9. The "with-defaults" Query Parameter . . . . . . . . . 55
5. Messages . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.1. Request URI Structure . . . . . . . . . . . . . . . . . . 57
5.2. Message Encoding . . . . . . . . . . . . . . . . . . . . 58
5.3. RESTCONF Metadata . . . . . . . . . . . . . . . . . . . . 59
5.3.1. XML Metadata Encoding Example . . . . . . . . . . . . 60
5.3.2. JSON Metadata Encoding Example . . . . . . . . . . . 60
5.4. Return Status . . . . . . . . . . . . . . . . . . . . . . 61
5.5. Message Caching . . . . . . . . . . . . . . . . . . . . . 61
6. Notifications . . . . . . . . . . . . . . . . . . . . . . . . 62
6.1. Server Support . . . . . . . . . . . . . . . . . . . . . 62
6.2. Event Streams . . . . . . . . . . . . . . . . . . . . . . 62
6.3. Subscribing to Receive Notifications . . . . . . . . . . 64
6.3.1. NETCONF Event Stream . . . . . . . . . . . . . . . . 65
6.4. Receiving Event Notifications . . . . . . . . . . . . . . 65
7. Error Reporting . . . . . . . . . . . . . . . . . . . . . . . 67
7.1. Error Response Message . . . . . . . . . . . . . . . . . 68
8. RESTCONF Module . . . . . . . . . . . . . . . . . . . . . . . 70
9. RESTCONF Monitoring . . . . . . . . . . . . . . . . . . . . . 77
9.1. restconf-state/capabilities . . . . . . . . . . . . . . . 77
9.1.1. Query Parameter URIs . . . . . . . . . . . . . . . . 78
9.1.2. The "defaults" Protocol Capability URI . . . . . . . 78
9.2. restconf-state/streams . . . . . . . . . . . . . . . . . 79
9.3. RESTCONF Monitoring Module . . . . . . . . . . . . . . . 79
10. YANG Module Library . . . . . . . . . . . . . . . . . . . . . 83
10.1. modules-state/module . . . . . . . . . . . . . . . . . . 83
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 83
11.1. The "restconf" Relation Type . . . . . . . . . . . . . . 84
11.2. YANG Module Registry . . . . . . . . . . . . . . . . . . 84
11.3. Media Types . . . . . . . . . . . . . . . . . . . . . . 85
11.3.1. Media Type application/yang-data+xml . . . . . . . . 85
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11.3.2. Media Type application/yang-data+json . . . . . . . 86
11.4. RESTCONF Capability URNs . . . . . . . . . . . . . . . . 88
12. Security Considerations . . . . . . . . . . . . . . . . . . . 89
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 90
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 90
14.1. Normative References . . . . . . . . . . . . . . . . . . 90
14.2. Informative References . . . . . . . . . . . . . . . . . 93
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 93
A.1. v16 to v17 . . . . . . . . . . . . . . . . . . . . . . . 93
A.2. v15 to v16 . . . . . . . . . . . . . . . . . . . . . . . 94
A.3. v14 to v15 . . . . . . . . . . . . . . . . . . . . . . . 94
A.4. v13 - v14 . . . . . . . . . . . . . . . . . . . . . . . . 95
A.5. v12 - v13 . . . . . . . . . . . . . . . . . . . . . . . . 96
A.6. v11 - v12 . . . . . . . . . . . . . . . . . . . . . . . . 97
A.7. v10 - v11 . . . . . . . . . . . . . . . . . . . . . . . . 97
A.8. v09 - v10 . . . . . . . . . . . . . . . . . . . . . . . . 98
A.9. v08 - v09 . . . . . . . . . . . . . . . . . . . . . . . . 100
A.10. v07 - v08 . . . . . . . . . . . . . . . . . . . . . . . . 100
A.11. v06 - v07 . . . . . . . . . . . . . . . . . . . . . . . . 100
A.12. v05 - v06 . . . . . . . . . . . . . . . . . . . . . . . . 101
A.13. v04 - v05 . . . . . . . . . . . . . . . . . . . . . . . . 101
A.14. v03 - v04 . . . . . . . . . . . . . . . . . . . . . . . . 102
A.15. v02 - v03 . . . . . . . . . . . . . . . . . . . . . . . . 102
A.16. v01 - v02 . . . . . . . . . . . . . . . . . . . . . . . . 103
A.17. v00 - v01 . . . . . . . . . . . . . . . . . . . . . . . . 104
A.18. bierman:restconf-04 to ietf:restconf-00 . . . . . . . . . 105
Appendix B. Open Issues . . . . . . . . . . . . . . . . . . . . 105
Appendix C. Example YANG Module . . . . . . . . . . . . . . . . 105
C.1. example-jukebox YANG Module . . . . . . . . . . . . . . . 106
Appendix D. RESTCONF Message Examples . . . . . . . . . . . . . 111
D.1. Resource Retrieval Examples . . . . . . . . . . . . . . . 111
D.1.1. Retrieve the Top-level API Resource . . . . . . . . . 111
D.1.2. Retrieve The Server Module Information . . . . . . . 112
D.1.3. Retrieve The Server Capability Information . . . . . 114
D.2. Edit Resource Examples . . . . . . . . . . . . . . . . . 115
D.2.1. Create New Data Resources . . . . . . . . . . . . . . 115
D.2.2. Detect Resource Entity-Tag Change . . . . . . . . . . 117
D.2.3. Edit a Datastore Resource . . . . . . . . . . . . . . 117
D.2.4. Edit a Data Resource . . . . . . . . . . . . . . . . 118
D.3. Query Parameter Examples . . . . . . . . . . . . . . . . 118
D.3.1. "content" Parameter . . . . . . . . . . . . . . . . . 119
D.3.2. "depth" Parameter . . . . . . . . . . . . . . . . . . 122
D.3.3. "fields" Parameter . . . . . . . . . . . . . . . . . 125
D.3.4. "insert" Parameter . . . . . . . . . . . . . . . . . 126
D.3.5. "point" Parameter . . . . . . . . . . . . . . . . . . 127
D.3.6. "filter" Parameter . . . . . . . . . . . . . . . . . 128
D.3.7. "start-time" Parameter . . . . . . . . . . . . . . . 129
D.3.8. "stop-time" Parameter . . . . . . . . . . . . . . . . 129
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D.3.9. "with-defaults" Parameter . . . . . . . . . . . . . . 130
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 131
1. Introduction
There is a need for standard mechanisms to allow Web applications to
access the configuration data, state data, data-model-specific RPC
operations, and event notifications within a networking device, in a
modular and extensible manner.
This document defines an HTTP [RFC7230] based protocol called
RESTCONF, for configuring data defined in YANG version 1 [RFC6020] or
YANG version 1.1 [RFC7950], using the datastore concepts defined in
NETCONF [RFC6241].
NETCONF defines configuration datastores and a set of Create,
Retrieve, Update, Delete (CRUD) operations that can be used to access
these datastores. NETCONF also defines a protocol for invoking these
operations. The YANG language defines the syntax and semantics of
datastore content, configuration, state data, RPC operations, and
event notifications.
RESTCONF uses HTTP methods to provide CRUD operations on a conceptual
datastore containing YANG-defined data, which is compatible with a
server which implements NETCONF datastores.
If a RESTCONF server is co-located with a NETCONF server, then there
are protocol interactions with the NETCONF protocol, which are
described in Section 1.4. The RESTCONF server MAY provide access to
specific datastores using operation resources, as described in
Section 3.6. The RESTCONF protocol does not specify any mandatory
operation resources. The semantics of each operation resource
determine if and how datastores are accessed.
Configuration data and state data are exposed as resources that can
be retrieved with the GET method. Resources representing
configuration data can be modified with the DELETE, PATCH, POST, and
PUT methods. Data is encoded with either XML [W3C.REC-xml-20081126]
or JSON [RFC7159].
Data-model-specific RPC operations defined with the YANG "rpc" or
"action" statements can be invoked with the POST method. Data-model-
specific event notifications defined with the YANG "notification"
statement can be accessed.
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1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
1.1.1. NETCONF
The following terms are defined in [RFC6241]:
o candidate configuration datastore
o configuration data
o datastore
o configuration datastore
o running configuration datastore
o startup configuration datastore
o state data
o user
1.1.2. HTTP
The following terms are defined in [RFC3986]:
o fragment
o path
o query
The following terms are defined in [RFC7230]:
o header field
o message-body
o request-line
o request URI
o status-line
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The following terms are defined in [RFC7231]:
o method
o request
o resource
The following terms are defined in [RFC7232]:
o entity-tag
1.1.3. YANG
The following terms are defined in [RFC7950]:
o action
o container
o data node
o key leaf
o leaf
o leaf-list
o list
o mandatory node
o ordered-by user
o presence container
o RPC operation
o top-level data node
1.1.4. NETCONF Notifications
The following terms are defined in [RFC5277]:
o notification replay
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1.1.5. Terms
The following terms are used within this document:
o API resource: the resource that models the RESTCONF root resource
and the sub-resources to access YANG-defined content. It is
defined with the YANG data template named "yang-api" in the
"ietf-restconf" module.
o client: a RESTCONF client
o data resource: a resource that models a YANG data node. It is
defined with YANG data definition statements.
o datastore resource: the resource that models a programmatic
interface using NETCONF datastore concepts. By default, RESTCONF
methods access a unified view of the underlying datastore
implementation on the server. It is defined as a sub-resource
within the API resource.
o edit operation: a RESTCONF operation on a data resource using
either a POST, PUT, PATCH, or DELETE method. This is not the same
as the NETCONF edit operation (i.e., one of the values for the
"nc:operation" attribute: "create", "replace", "merge", "delete",
or "remove").
o event stream resource: This resource represents an SSE (Server-
Sent Events) event stream. The content consists of text using the
media type "text/event-stream", as defined by the SSE
[W3C.REC-eventsource-20150203] specification. Event stream
contents are described in Section 3.8.
o media-type: HTTP uses Internet media types [RFC2046] in the
Content-Type and Accept header fields in order to provide open and
extensible data typing and type negotiation.
o NETCONF client: a client which implements the NETCONF protocol.
Called "client" in [RFC6241].
o NETCONF server: a server which implements the NETCONF protocol.
Called "server" in [RFC6241].
o operation: the conceptual RESTCONF operation for a message,
derived from the HTTP method, request URI, header fields, and
message-body.
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o operation resource: a resource that models a data-model-specific
operation, that is defined with a YANG "rpc" or "action"
statement. It is invoked with the POST method.
o patch: a PATCH method on the target datastore or data resource.
The media type of the message-body content will identify the patch
type in use.
o plain patch: a specific media type for use with the PATCH method,
defined in Section 4.6.1, that can be used for simple merge
operations. It is specified by a request Content-Type of
"application/yang-data+xml" or "application/yang-data+json".
o query parameter: a parameter (and its value if any), encoded
within the query component of the request URI.
o resource type: one of the RESTCONF resource classes defined in
this document. One of "api", "datastore", "data", "operation",
"schema", or "event stream".
o RESTCONF capability: An optional RESTCONF protocol feature
supported by the server, which is identified by an IANA registered
NETCONF Capability URI, and advertised with an entry in the
"capability" leaf-list defined in Section 9.3.
o RESTCONF client: a client which implements the RESTCONF protocol.
o RESTCONF server: a server which implements the RESTCONF protocol.
o retrieval request: a request using the GET or HEAD methods.
o schema resource: a resource that used by the client to retrieve a
YANG schema with the GET method. It has a representation with the
media type "application/yang".
o server: a RESTCONF server
o stream list: the set of data resource instances that describe the
event stream resources available from the server. This
information is defined in the "ietf-restconf-monitoring" module as
the "stream" list. It can be retrieved using the target resource
"{+restconf}/data/ietf-restconf-monitoring:restconf-state/streams/
stream". The stream list contains information about each stream,
such as the URL to retrieve the event stream data.
o stream resource: An event stream resource.
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o target resource: the resource that is associated with a particular
message, identified by the "path" component of the request URI.
o yang-data extension: A YANG external statement that conforms to
the "yang-data" extension statement found in Section 8. The yang-
data extension is used to define YANG data structures that are
meant to be used as YANG data templates. These data structures
are not intended to be implemented as part of a configuration
datastore or as operational state within the server, so normal
YANG data definition statements cannot be used.
o YANG data template: a schema for modeling protocol message
components as conceptual data structure using YANG. This allows
the messages to be defined in an encoding-independent manner.
Each YANG data template is defined with the "yang-data" extension,
found in Section 8. Representations of instances conforming to a
particular YANG data template can be defined for YANG. The XML
representation is defined in YANG version 1.1 [RFC7950], and
supported with the "application/yang-data+xml" media type. The
JSON representation is defined in JSON Encoding of Data Modeled
with YANG [RFC7951], and supported with the "application/
yang-data+json" media type.
1.1.6. URI Template and Examples
Throughout this document, the URI template [RFC6570] syntax
"{+restconf}" is used to refer to the RESTCONF root resource outside
of an example. See Section 3.1 for details.
For simplicity, all of the examples in this document use "/restconf"
as the discovered RESTCONF API root path. Many of the examples
throughout the document are based on the "example-jukebox" YANG
module, defined in Appendix C.1.
Many protocol header lines and message-body text within examples
throughout the document are split into multiple lines for display
purposes only. When a line ends with backslash ('\') as the last
character, the line is wrapped for display purposes. It is to be
considered to be joined to the next line by deleting the backslash,
the following line break, and the leading whitespace of the next
line.
1.1.7. Tree Diagrams
A simplified graphical representation of the data model is used in
this document. The meaning of the symbols in these diagrams is as
follows:
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o Brackets "[" and "]" enclose list keys.
o Abbreviations before data node names: "rw" means configuration
data (read-write), "ro" state data (read-only), and "x" operation
resource (executable)
o Symbols after data node names: "?" means an optional node, "!"
means a presence container, and "*" denotes a list and leaf-list.
o Parentheses enclose choice and case nodes, and case nodes are also
marked with a colon (":").
o Ellipsis ("...") stands for contents of subtrees that are not
shown.
1.2. Subset of NETCONF Functionality
RESTCONF does not need to mirror the full functionality of the
NETCONF protocol, but it does need to be compatible with NETCONF.
RESTCONF achieves this by implementing a subset of the interaction
capabilities provided by the NETCONF protocol, for instance, by
eliminating datastores and explicit locking.
RESTCONF uses HTTP methods to implement the equivalent of NETCONF
operations, enabling basic CRUD operations on a hierarchy of
conceptual resources.
The HTTP POST, PUT, PATCH, and DELETE methods are used to edit data
resources represented by YANG data models. These basic edit
operations allow the running configuration to be altered by a
RESTCONF client.
RESTCONF is not intended to replace NETCONF, but rather provide an
HTTP interface that follows Representational State Transfer (REST)
principles [rest-dissertation], and is compatible with the NETCONF
datastore model.
1.3. Data Model Driven API
RESTCONF combines the simplicity of the HTTP protocol with the
predictability and automation potential of a schema-driven API.
Knowing the YANG modules used by the server, a client can derive all
management resource URLs and the proper structure of all RESTCONF
requests and responses. This strategy obviates the need for
responses provided by the server to contain Hypermedia as the Engine
of Application State (HATEOAS) links, originally described in Roy
Fielding's doctoral dissertation [rest-dissertation], because the
client can determine the links it needs from the YANG modules.
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RESTCONF utilizes the YANG Library [RFC7895] to allow a client to
discover the YANG module conformance information for the server, in
case the client wants to use it.
The server can optionally support retrieval of the YANG modules it
uses, as identified in its YANG library. See Section 3.7 for
details.
The URIs for data-model-specific RPC operations and datastore content
are predictable, based on the YANG module definitions.
The RESTCONF protocol operates on a conceptual datastore defined with
the YANG data modeling language. The server lists each YANG module
it supports using the "ietf-yang-library" YANG module, defined in
[RFC7895]. The server MUST implement the "ietf-yang-library" module,
which MUST identify all the YANG modules used by the server, in the
"modules-state/module" list. The conceptual datastore contents,
data-model-specific RPC operations and event notifications are
identified by this set of YANG modules.
The classification of data as configuration or non-configuration is
derived from the YANG "config" statement. Data ordering behavior is
derived from the YANG "ordered-by" statement. Non-configuration data
is also called "state data".
The RESTCONF datastore editing model is simple and direct, similar to
the behavior of the :writable-running capability in NETCONF. Each
RESTCONF edit of a data resource within the datastore resource is
activated upon successful completion of the edit.
1.4. Coexistence with NETCONF
RESTCONF can be implemented on a device that supports the NETCONF
protocol.
The following figure shows the system components if a RESTCONF server
is co-located with a NETCONF server:
+-----------+ +-----------------+
| Web app | <-------> | |
+-----------+ RESTCONF | network device |
| |
+-----------+ | +-----------+ |
| NETCONF | <-------> | | datastore | |
| Client | NETCONF | | | |
+-----------+ | +-----------+ |
+-----------------+
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The following figure shows the system components if a RESTCONF server
is implemented in a device that does not have a NETCONF server:
+-----------+ +-----------------+
| Web app | <-------> | |
+-----------+ RESTCONF | network device |
| |
+-----------------+
Note that there are no interactions at all between the NETCONF
protocol and RESTCONF protocol. It is possible that locks are in use
on a RESTCONF server, even though RESTCONF cannot manipulate locks.
In such a case, the RESTCONF protocol will not be granted write
access to data resources within a datastore.
If the NETCONF server supports :writable-running, all edits to
configuration nodes in {+restconf}/data are performed in the running
configuration datastore. The URI template "{+restconf}" is defined
in Section 1.1.6.
Otherwise, if the device supports :candidate, all edits to
configuration nodes in {+restconf}/data are performed in the
candidate configuration datastore. The candidate MUST be
automatically committed to running immediately after each successful
edit. Any edits from other sources that are in the candidate
datastore will also be committed. If a confirmed commit procedure is
in progress by any NETCONF client, then this commit will act as the
confirming commit. If the NETCONF server is expecting a "persist-id"
parameter to complete the confirmed commit procedure then the
RESTCONF edit operation MUST fail with a "409 Conflict" status-line.
There error-tag "in-use" is returned in this case. The error-tag
value "resource-denied" is used in this case.
If the NETCONF server supports :startup, the RESTCONF server MUST
automatically update the non-volatile startup configuration
datastore, after the running datastore has been altered as a
consequence of a RESTCONF edit operation.
If a datastore that would be modified by a RESTCONF operation has an
active lock from a NETCONF client, the RESTCONF edit operation MUST
fail with a "409 Conflict" status-line. There error-tag "in-use" is
returned in this case.
1.5. RESTCONF Extensibility
There are two extensibility mechanisms built into RESTCONF:
o protocol version
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o optional capabilities
This document defines version 1 of the RESTCONF protocol. If a
future version of this protocol is defined, then that document will
specify how the new version of RESTCONF is identified. It is
expected that a different RESTCONF root resource will be used which
will be located using a different link relation (See Section 3.1).
The server will advertise all protocol versions that it supports in
its host-meta data.
In this example, the server supports both RESTCONF version 1 and a
fictitious version 2.
The client might send:
GET /.well-known/host-meta HTTP/1.1
Host: example.com
Accept: application/xrd+xml
The server might respond:
HTTP/1.1 200 OK
Content-Type: application/xrd+xml
Content-Length: nnn
RESTCONF also supports a server-defined list of optional
capabilities, which are listed by a server using the
"ietf-restconf-monitoring" module defined in Section 9.3. This
document defines several query parameters in Section 4.8. Each
optional parameter has a corresponding capability URI defined in
Section 9.1.1 that is advertised by the server if supported.
The "capabilities" list can identify any sort of server extension.
Currently this extension mechanism is used to identify optional query
parameters that are supported, but it is not limited to that purpose.
For example, the "defaults" URI defined in Section 9.1.2 specifies a
mandatory URI identifying server defaults handling behavior.
A new sub-resource type could be identified with a capability if it
is optional to implement. Mandatory protocol features and new
resource types require a new revision of the RESTCONF protocol.
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2. Transport Protocol Requirements
2.1. Integrity and Confidentiality
HTTP [RFC7230] is an application layer protocol that may be layered
on any reliable transport-layer protocol. RESTCONF is defined on top
of HTTP, but due to the sensitive nature of the information conveyed,
RESTCONF requires that the transport-layer protocol provides both
data integrity and confidentiality. A RESTCONF server MUST support
the TLS protocol [RFC5246]. The RESTCONF protocol MUST NOT be used
over HTTP without using the TLS protocol.
RESTCONF does not require a specific version of HTTP. However, it is
RECOMMENDED that at least HTTP/1.1 [RFC7230] be supported by all
implementations.
2.2. HTTPS with X.509v3 Certificates
Given the nearly ubiquitous support for HTTP over TLS [RFC7230],
RESTCONF implementations MUST support the "https" URI scheme, which
has the IANA assigned default port 443.
RESTCONF servers MUST present an X.509v3 based certificate when
establishing a TLS connection with a RESTCONF client. The use of
X.509v3 based certificates is consistent with NETCONF over TLS
[RFC7589].
2.3. Certificate Validation
The RESTCONF client MUST either use X.509 certificate path validation
[RFC5280] to verify the integrity of the RESTCONF server's TLS
certificate, or match the server's TLS certificate with a certificate
obtained by a trusted mechanism (e.g. a pinned certificate). If
X.509 certificate path validation fails, and the presented X.509
certificate does not match a certificate obtained by a trusted
mechanism, the connection MUST be terminated, as described in
Section 7.2.1 of [RFC5246].
2.4. Authenticated Server Identity
The RESTCONF client MUST check the identity of the server according
to Section 6 of [RFC6125], including processing the outcome as
described in Section 6.6 of [RFC6125].
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2.5. Authenticated Client Identity
The RESTCONF server MUST authenticate client access to any protected
resource. If the RESTCONF client is not authenticated, the server
SHOULD send an HTTP response with "401 Unauthorized" status-line, as
defined in Section 3.1 of [RFC7235]. The error-tag value
"access-denied" is used in this case.
To authenticate a client, a RESTCONF server MUST use TLS based client
certificates (Section 7.4.6 of [RFC5246]), or MUST use any HTTP
authentication scheme defined in the HTTP Authentication Scheme
Registry (Section 5.1 in [RFC7235]). A server MAY also support the
combination of both client certificates and an HTTP client
authentication scheme, with the determination of how to process this
combination left as an implementation decision.
The RESTCONF client identity derived from the authentication
mechanism used is hereafter known as the "RESTCONF username" and
subject to the NETCONF Access Control Module (NACM) [RFC6536]. When
a client certificate is presented, the RESTCONF username MUST be
derived using the algorithm defined in Section 7 of [RFC7589]. For
all other cases, when HTTP authentication is used, the RESTCONF
username MUST be provided by the HTTP authentication scheme used.
3. Resources
The RESTCONF protocol operates on a hierarchy of resources, starting
with the top-level API resource itself (Section 3.1). Each resource
represents a manageable component within the device.
A resource can be considered as a collection of data and the set of
allowed methods on that data. It can contain nested child resources.
The child resource types and methods allowed on them are data-model-
specific.
A resource has a representation associated with a media type
identifier, as represented by the "Content-Type" header field in the
HTTP response message. A resource has one or more representations,
each associated with a different media type. When a representation
of a resource is sent in an HTTP message, the associated media type
is given in the "Content-Type" header. A resource can contain zero
or more nested resources. A resource can be created and deleted
independently of its parent resource, as long as the parent resource
exists.
The RESTCONF resources are accessed via a set of URIs defined in this
document. The set of YANG modules supported by the server will
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determine the data model specific RPC operations, top-level data
nodes, and event notification messages supported by the server.
The RESTCONF protocol does not include a data resource discovery
mechanism. Instead, the definitions within the YANG modules
advertised by the server are used to construct an RPC operation or
data resource identifier.
3.1. Root Resource Discovery
In line with the best practices defined by [RFC7320], RESTCONF
enables deployments to specify where the RESTCONF API is located.
When first connecting to a RESTCONF server, a RESTCONF client MUST
determine the root of the RESTCONF API. There MUST be exactly one
"restconf" link relation returned by the device.
The client discovers this by getting the "/.well-known/host-meta"
resource ([RFC6415]) and using the element containing the
"restconf" attribute :
Example returning /restconf:
The client might send:
GET /.well-known/host-meta HTTP/1.1
Host: example.com
Accept: application/xrd+xml
The server might respond:
HTTP/1.1 200 OK
Content-Type: application/xrd+xml
Content-Length: nnn
After discovering the RESTCONF API root, the client MUST use this
value as the initial part of the path in the request URI, in any
subsequent request for a RESTCONF resource.
In this example, the client would use the path "/restconf" as the
RESTCONF root resource.
Example returning /top/restconf:
The client might send:
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GET /.well-known/host-meta HTTP/1.1
Host: example.com
Accept: application/xrd+xml
The server might respond:
HTTP/1.1 200 OK
Content-Type: application/xrd+xml
Content-Length: nnn
In this example, the client would use the path "/top/restconf" as the
RESTCONF root resource.
The client can now determine the operation resources supported by the
the server. In this example a custom "play" operation is supported:
The client might send:
GET /top/restconf/operations HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Cache-Control: no-cache
Last-Modified: Sun, 22 Apr 2016 01:00:14 GMT
Content-Type: application/yang-data+json
{ "operations" : { "example-jukebox:play" : [null] } }
If the Extensible Resource Descriptor (XRD) contains more than one
link relation, then only the relation named "restconf" is relevant to
this specification.
Note that any given endpoint (host:port) can only support one
RESTCONF server, due to the root resource discovery mechanism. This
limits the number of RESTCONF servers that can run concurrently on a
host, since each server must use a different port.
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3.2. RESTCONF Media Types
The RESTCONF protocol defines two application specific media types to
identify representations of data which conforms to the schema for a
particular YANG construct.
This document defines media types for XML and JSON serialization of
YANG data. Other documents MAY define other media types for
different serializations of YANG data. The "application/
yang-data+xml" media-type is defined in Section 11.3.1. The
"application/yang-data+json" media-type is defined in Section 11.3.2.
3.3. API Resource
The API resource contains the RESTCONF root resource for the RESTCONF
datastore and operation resources. It is the top-level resource
located at {+restconf} and has the media type "application/
yang-data+xml" or "application/yang-data+json".
YANG Tree Diagram for an API Resource:
+---- {+restconf}
+---- data
| ...
+---- operations?
| ...
+--ro yang-library-version string
The "yang-api" YANG data template is defined using the "yang-data"
extension in the "ietf-restconf" module, found in Section 8. It
specifies the structure and syntax of the conceptual child resources
within the API resource.
The API resource can be retrieved with the GET method.
The {+restconf} root resource name used in responses representing the
root of the "ietf-restconf" module MUST identify the "ietf-restconf"
YANG module. For example, a request to GET the root resource
"/restconf" in JSON format will return a representation of the API
resource named "ietf-restconf:restconf".
This resource has the following child resources:
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+----------------------+--------------------------------+
| Child Resource | Description |
+----------------------+--------------------------------+
| data | Contains all data resources |
| operations | Data-model-specific operations |
| yang-library-version | ietf-yang-library module date |
+----------------------+--------------------------------+
RESTCONF API Resource
3.3.1. {+restconf}/data
This mandatory resource represents the combined configuration and
state data resources that can be accessed by a client. It cannot be
created or deleted by the client. The datastore resource type is
defined in Section 3.4.
Example:
This example request by the client would retrieve only the non-
configuration data nodes that exist within the "library" resource,
using the "content" query parameter (see Section 4.8.1).
GET /restconf/data/example-jukebox:jukebox/library\
?content=nonconfig HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+xml
4259374
3.3.2. {+restconf}/operations
This optional resource is a container that provides access to the
data-model-specific RPC operations supported by the server. The
server MAY omit this resource if no data-model-specific RPC
operations are advertised.
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Any data-model-specific RPC operations defined in the YANG modules
advertised by the server MUST be available as child nodes of this
resource.
The access point for each RPC operation is represented as an empty
leaf. If an operation resource is retrieved, the empty leaf
representation is returned by the server.
Operation resources are defined in Section 3.6.
3.3.3. {+restconf}/yang-library-version
This mandatory leaf identifies the revision date of the
"ietf-yang-library" YANG module that is implemented by this server.
Note that the revision date for the module version found in [RFC7895]
is used.
Example:
GET /restconf/yang-library-version HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+xml
\
2016-06-21\
3.4. Datastore Resource
The "{+restconf}/data" subtree represents the datastore resource,
which is a collection of configuration data and state data nodes.
This resource type is an abstraction of the system's underlying
datastore implementation. The client uses it to edit and retrieve
data resources, as the conceptual root of all configuration and state
data that is present on the device.
Configuration edit transaction management and configuration
persistence are handled by the server and not controlled by the
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client. A datastore resource can be written directly with the POST
and PATCH methods. Each RESTCONF edit of a datastore resource is
saved to non-volatile storage by the server, if the server supports
non-volatile storage of configuration data, as described in
Section 1.4.
If the datastore resource represented by the "{+restconf}/data"
subtree is retrieved, then the datastore and its contents are
returned by the server. The datastore is represented by a node named
"data" in the "ietf-restconf" module namespace.
3.4.1. Edit Collision Prevention
Two edit collision detection and prevention mechanisms are provided
in RESTCONF for the datastore resource: a timestamp and an entity-
tag. Any change to configuration data resources updates the
timestamp and entity tag of the datastore resource. In addition, the
RESTCONF server MUST return an error if the datastore is locked by an
external source (e.g., NETCONF server).
3.4.1.1. Timestamp
The last change time is maintained and the "Last-Modified"
([RFC7232], Section 2.2) header field is returned in the response for
a retrieval request. The "If-Unmodified-Since" header field
([RFC7232], Section 3.4) can be used in edit operation requests to
cause the server to reject the request if the resource has been
modified since the specified timestamp.
The server SHOULD maintain a last-modified timestamp for the
datastore resource, defined in Section 3.4. This timestamp is only
affected by configuration child data resources, and MUST NOT be
updated for changes to non-configuration child data resources. Last-
modified timestamps for data resources are discussed in Section 3.5.
If the RESTCONF server is colocated with a NETCONF server, then the
last-modified timestamp MUST be for the "running" datastore. Note
that it is possible other protocols can cause the last-modified
timestamp to be updated. Such mechanisms are out of scope for this
document.
3.4.1.2. Entity-Tag
The server MUST maintain a unique opaque entity-tag for the datastore
resource and MUST return it in the "ETag" ([RFC7232], Section 2.3)
header in the response for a retrieval request. The client MAY use
an "If-Match" header in edit operation requests to cause the server
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to reject the request if the resource entity-tag does not match the
specified value.
The server MUST maintain an entity-tag for the top-level
{+restconf}/data resource. This entity-tag is only affected by
configuration data resources, and MUST NOT be updated for changes to
non-configuration data. Entity-tags for data resources are discussed
in Section 3.5. Note that each representation (e.g. XML vs. JSON)
requires a different entity-tag.
If the RESTCONF server is colocated with a NETCONF server, then this
entity-tag MUST be for the "running" datastore. Note that it is
possible other protocols can cause the entity-tag to be updated.
Such mechanisms are out of scope for this document.
3.4.1.3. Update Procedure
Changes to configuration data resources affect the timestamp and
entity-tag for that resource, any ancestor data resources, and the
datastore resource.
For example, an edit to disable an interface might be done by setting
the leaf "/interfaces/interface/enabled" to "false". The "enabled"
data node and its ancestors (one "interface" list instance, and the
"interfaces" container) are considered to be changed. The datastore
is considered to be changed when any top-level configuration data
node is changed (e.g., "interfaces").
3.5. Data Resource
A data resource represents a YANG data node that is a descendant node
of a datastore resource. Each YANG-defined data node can be uniquely
targeted by the request-line of an HTTP method. Containers, leafs,
leaf-list entries, list entries, anydata and anyxml nodes are data
resources.
The representation maintained for each data resource is the YANG
defined subtree for that node. HTTP methods on a data resource
affect both the targeted data node and all its descendants, if any.
A data resource can be retrieved with the GET method. Data resources
are accessed via the "{+restconf}/data" URI. This sub-tree is used
to retrieve and edit data resources.
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3.5.1. Timestamp
For configuration data resources, the server MAY maintain a last-
modified timestamp for the resource, and return the "Last-Modified"
header field when it is retrieved with the GET or HEAD methods.
The "Last-Modified" header field can be used by a RESTCONF client in
subsequent requests, within the "If-Modified-Since" and
"If-Unmodified-Since" header fields.
If maintained, the resource timestamp MUST be set to the current time
whenever the resource or any configuration resource within the
resource is altered. If not maintained, then the resource timestamp
for the datastore MUST be used instead. If the RESTCONF server is
colocated with a NETCONF server, then the last-modified timestamp for
a configuration data resource MUST represent the instance within the
"running" datastore.
This timestamp is only affected by configuration data resources, and
MUST NOT be updated for changes to non-configuration data.
3.5.2. Entity-Tag
For configuration data resources, the server SHOULD maintain a
resource entity-tag for each resource, and return the "ETag" header
field when it is retrieved as the target resource with the GET or
HEAD methods. If maintained, the resource entity-tag MUST be updated
whenever the resource or any configuration resource within the
resource is altered. If not maintained, then the resource entity-tag
for the datastore MUST be used instead.
The "ETag" header field can be used by a RESTCONF client in
subsequent requests, within the "If-Match" and "If-None-Match" header
fields.
This entity-tag is only affected by configuration data resources, and
MUST NOT be updated for changes to non-configuration data. If the
RESTCONF server is colocated with a NETCONF server, then the entity-
tag for a configuration data resource MUST represent the instance
within the "running" datastore.
3.5.3. Encoding Data Resource Identifiers in the Request URI
In YANG, data nodes can be identified with an absolute XPath
expression, defined in [XPath], starting from the document root to
the target resource. In RESTCONF, URI-encoded path expressions are
used instead.
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A predictable location for a data resource is important, since
applications will code to the YANG data model module, which uses
static naming and defines an absolute path location for all data
nodes.
A RESTCONF data resource identifier is encoded from left to right,
starting with the top-level data node, according to the "api-path"
rule in Section 3.5.3.1. The node name of each ancestor of the
target resource node is encoded in order, ending with the node name
for the target resource. If a node in the path is defined in another
module than its parent node, or its parent is the datastore, then the
module name followed by a colon character (":") MUST be prepended to
the node name in the resource identifier. See Section 3.5.3.1 for
details.
If a data node in the path expression is a YANG leaf-list node, then
the leaf-list value MUST be encoded according to the following rules:
o The identifier for the leaf-list MUST be encoded using one path
segment [RFC3986].
o The path segment is constructed by having the leaf-list name,
followed by an "=" character, followed by the leaf-list value.
(e.g., /restconf/data/top-leaflist=fred).
o The leaf-list value is specified as a string, using the canonical
representation for the YANG data type. Any reserved characters
MUST be percent-encoded, according to [RFC3986], section 2.1 and
2.5.
o YANG 1.1 allows duplicate leaf-list values for non-configuration
data. In this case there is no mechanism to specify the exact
matching leaf-list instance.
o The comma (',') character is percent-encoded, even though multiple
key values are not possible for a leaf-list. This is more
consistent and avoids special processing rules.
If a data node in the path expression is a YANG list node, then the
key values for the list (if any) MUST be encoded according to the
following rules:
o The key leaf values for a data resource representing a YANG list
MUST be encoded using one path segment [RFC3986].
o If there is only one key leaf value, the path segment is
constructed by having the list name, followed by an "=" character,
followed by the single key leaf value.
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o If there are multiple key leaf values, the path segment is
constructed by having the list name, followed by the value of each
leaf identified in the "key" statement, encoded in the order
specified in the YANG "key" statement. Each key leaf value except
the last one is followed by a comma character.
o The key value is specified as a string, using the canonical
representation for the YANG data type. Any reserved characters
MUST be percent-encoded, according to [RFC3986], section 2.1 and
2.5. The comma (',') character MUST be percent-encoded if it is
present in the key value.
o All the components in the "key" statement MUST be encoded.
Partial instance identifiers are not supported.
o Missing key values are not allowed, so two consecutive commas are
interpreted as a comma, followed by a zero-length string, followed
by a comma. For example, "list1=foo,,baz" would be interpreted as
a list named "list1" with 3 key values, and the second key value
is a zero-length string.
o Note that non-configuration lists are not required to define keys.
In this case, a single list instance cannot be accessed.
o The "list-instance" ABNF rule defined in Section 3.5.3.1
represents the syntax of a list instance identifier.
Examples:
container top {
list list1 {
key "key1 key2 key3";
...
list list2 {
key "key4 key5";
...
leaf X { type string; }
}
}
leaf-list Y {
type uint32;
}
}
For the above YANG definition, the container "top" is defined in the
"example-top" YANG module, and a target resource URI for leaf "X"
would be encoded as follows:
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/restconf/data/example-top:top/list1=key1,key2,key3/\
list2=key4,key5/X
For the above YANG definition, a target resource URI for leaf-list
"Y" would be encoded as follows:
/restconf/data/example-top:top/Y=instance-value
The following example shows how reserved characters are percent-
encoded within a key value. The value of "key1" contains a comma,
single-quote, double-quote, colon, double-quote, space, and forward
slash. (,'":" /). Note that double-quote is not a reserved character
and does not need to be percent-encoded. The value of "key2" is the
empty string, and the value of "key3" is the string "foo".
Example URL:
/restconf/data/example-top:top/list1=%2C%27"%3A"%20%2F,,foo
3.5.3.1. ABNF For Data Resource Identifiers
The "api-path" Augmented Backus-Naur Form (ABNF) syntax is used to
construct RESTCONF path identifiers. Note that this syntax is used
for all resources, and the API path starts with the RESTCONF root
resource. Data resources are required to be identified under the
subtree "+{restconf}/data".
An identifier is not allowed to start with the case-insensitive
string "XML", according to YANG identifier rules. The syntax for
"api-identifier" and "key-value" MUST conform to the JSON identifier
encoding rules in Section 4 of [RFC7951]: The RESTCONF root resource
path is required. Additional sub-resource identifiers are optional.
The characters in a key value string are constrained, and some
characters need to be percent-encoded, as described in Section 3.5.3.
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api-path = root ["/" (api-identifier | list-instance)]*
root = string ;; replacement string for {+restconf}
api-identifier = [module-name ":"] identifier
module-name = identifier
list-instance = api-identifier "=" key-value ["," key-value]*
key-value = string ;; constrained chars are percent-encoded
string =
;; An identifier MUST NOT start with
;; (('X'|'x') ('M'|'m') ('L'|'l'))
identifier = (ALPHA / "_")
*(ALPHA / DIGIT / "_" / "-" / ".")
3.5.4. Default Handling
RESTCONF requires that a server report its default handling mode (see
Section 9.1.2 for details). If the optional "with-defaults" query
parameter is supported by the server, a client may use it to control
retrieval of default values (see Section 4.8.9 for details).
If a leaf or leaf-list is missing from the configuration and there is
a YANG-defined default for that data resource, then the server MUST
use the YANG-defined default as the configured value.
If the target of a GET method is a data node that represents a leaf
or leaf-list that has a default value, and the leaf or leaf-list has
not been instantiated yet, the server MUST return the default
value(s) that are in use by the server. In this case, the server
MUST ignore its basic-mode, described in Section 4.8.9, and return
the default value.
If the target of a GET method is a data node that represents a
container or list that has any child resources with default values,
for the child resources that have not been given value yet, the
server MAY return the default values that are in use by the server,
in accordance with its reported default handing mode and query
parameters passed by the client.
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3.6. Operation Resource
An operation resource represents an RPC operation defined with the
YANG "rpc" statement or a data-model-specific action defined with a
YANG "action" statement. It is invoked using a POST method on the
operation resource.
An RPC operation is invoked as:
POST {+restconf}/operations/
The field identifies the module name and rpc identifier
string for the desired operation.
For example, if "module-A" defined a "reset" rpc operation, then
invoking the operation would be requested as follows:
POST /restconf/operations/module-A:reset HTTP/1.1
Server: example.com
An action is invoked as:
POST {+restconf}/data//
where contains the path to the data node
where the action is defined, and is the name of the action.
For example, if "module-A" defined a "reset-all" action in the
container "interfaces", then invoking this action would be requested
as follows:
POST /restconf/data/module-A:interfaces/reset-all HTTP/1.1
Server: example.com
If the RPC operation is invoked without errors, and if the "rpc" or
"action" statement has no "output" section, the response message MUST
NOT include a message-body, and MUST send a "204 No Content" status-
line instead.
All operation resources representing RPC operations supported by the
server MUST be identified in the {+restconf}/operations subtree
defined in Section 3.3.2. Operation resources representing YANG
actions are not identified in this subtree since they are invoked
using a URI within the {+restconf}/data subtree.
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3.6.1. Encoding Operation Resource Input Parameters
If the "rpc" or "action" statement has an "input" section then
instances of these input parameters are encoded in the module
namespace where the "rpc" or "action" statement is defined, in an XML
element or JSON object named "input", which is in the module
namespace where the "rpc" or "action" statement is defined.
If the "rpc" or "action" statement has an "input" section and the
"input" object tree contains any child data nodes which are
considered mandatory nodes, then a message-body MUST be sent by the
client in the request.
If the "rpc" or "action" statement has an "input" section and the
"input" object tree does not contain any child nodes which are
considered mandatory nodes, then a message-body MAY be sent by the
client in the request.
If the "rpc" or "action" statement has no "input" section, the
request message MUST NOT include a message-body.
Examples:
The following YANG module is used for the RPC operation examples in
this section.
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module example-ops {
namespace "https://example.com/ns/example-ops";
prefix "ops";
organization "Example, Inc.";
contact "support at example.com";
description "Example Operations Data Model Module";
revision "2016-07-07" {
description "Initial version.";
reference "example.com document 3-3373";
}
rpc reboot {
input {
leaf delay {
units seconds;
type uint32;
default 0;
}
leaf message { type string; }
leaf language { type string; }
}
}
rpc get-reboot-info {
output {
leaf reboot-time {
units seconds;
type uint32;
}
leaf message { type string; }
leaf language { type string; }
}
}
}
The following YANG module is used for the YANG action examples in
this section.
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module example-actions {
yang-version 1.1;
namespace "https://example.com/ns/example-actions";
prefix "act";
import ietf-yang-types { prefix yang; }
organization "Example, Inc.";
contact "support at example.com";
description "Example Actions Data Model Module";
revision "2016-07-07" {
description "Initial version.";
reference "example.com document 2-9973";
}
revision "2016-03-10";
container interfaces {
list interface {
key name;
leaf name { type string; }
action reset {
input {
leaf delay {
units seconds;
type uint32;
default 0;
}
}
}
action get-last-reset-time {
output {
leaf last-reset {
type yang:date-and-time;
mandatory true;
}
}
}
}
}
}
RPC Input Example:
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The client might send the following POST request message to invoke
the "reboot" RPC operation:
POST /restconf/operations/example-ops:reboot HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
600Going down for system maintenanceen-US
The server might respond:
HTTP/1.1 204 No Content
Date: Mon, 25 Apr 2016 11:01:00 GMT
Server: example-server
The same example request message is shown here using JSON encoding:
POST /restconf/operations/example-ops:reboot HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{
"example-ops:input" : {
"delay" : 600,
"message" : "Going down for system maintenance",
"language" : "en-US"
}
}
Action Input Example:
The client might send the following POST request message to invoke
the "reset" action:
POST /restconf/data/example-actions:interfaces/\
interface=eth0/reset HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
600
The server might respond:
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HTTP/1.1 204 No Content
Date: Mon, 25 Apr 2016 11:01:00 GMT
Server: example-server
The same example request message is shown here using JSON encoding:
POST /restconf/data/example-actions:interfaces/\
interface=eth0/reset HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{ "example-actions:input" : {
"delay" : 600
}
}
3.6.2. Encoding Operation Resource Output Parameters
If the "rpc" or "action" statement has an "output" section then
instances of these output parameters are encoded in the module
namespace where the "rpc" or "action" statement is defined, in an XML
element or JSON object named "output", which is in the module
namespace where the "rpc" or "action" statement is defined.
If the RPC operation is invoked without errors, and if the "rpc" or
"action" statement has an "output" section and the "output" object
tree contains any child data nodes which are considered mandatory
nodes, then a response message-body MUST be sent by the server in the
response.
If the RPC operation is invoked without errors, and if the "rpc" or
"action" statement has an "output" section and the "output" object
tree does not contain any child nodes which are considered mandatory
nodes, then a response message-body MAY be sent by the server in the
response.
The request URI is not returned in the response. Knowledge of the
request URI may be needed to associate the output with the specific
"rpc" or "action" statement used in the request.
Examples:
RPC Output Example:
The "example-ops" YANG module defined in Section 3.6.1 is used for
this example.
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The client might send the following POST request message to invoke
the "get-reboot-info" operation:
POST /restconf/operations/example-ops:get-reboot-info HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 25 Apr 2016 11:10:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"example-ops:output" : {
"reboot-time" : 30,
"message" : "Going down for system maintenance",
"language" : "en-US"
}
}
The same response is shown here using XML encoding:
HTTP/1.1 200 OK
Date: Mon, 25 Apr 2016 11:10:30 GMT
Server: example-server
Content-Type: application/yang-data+xml
Action Output Example:
The "example-actions" YANG module defined in Section 3.6.1 is used
for this example.
The client might send the following POST request message to invoke
the "get-last-reset-time" action:
POST /restconf/data/example-actions:interfaces/\
interface=eth0/get-last-reset-time HTTP/1.1
Host: example.com
Accept: application/yang-data+json
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The server might respond:
HTTP/1.1 200 OK
Date: Mon, 25 Apr 2016 11:10:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"example-actions:output" : {
"last-reset" : "2015-10-10T02:14:11Z"
}
}
3.6.3. Encoding Operation Resource Errors
If any errors occur while attempting to invoke the operation or
action, then an "errors" media type is returned with the appropriate
error status.
If the RPC operation input is not valid, or the RPC operation is
invoked but errors occur, then a message-body MUST be sent by the
server, containing an "errors" resource, as defined in Section 3.9.
A detailed example of an operation resource error response can be
found in Section 3.6.3.
Using the "reboot" RPC operation from the example in Section 3.6.1,
the client might send the following POST request message:
POST /restconf/operations/example-ops:reboot HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
-33Going down for system maintenanceen-US
The server might respond with an "invalid-value" error:
HTTP/1.1 400 Bad Request
Date: Mon, 25 Apr 2016 11:10:30 GMT
Server: example-server
Content-Type: application/yang-data+xml
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protocolinvalid-value
/ops:input/ops:delay
Invalid input parameter
The same response is shown here in JSON encoding:
HTTP/1.1 400 Bad Request
Date: Mon, 25 Apr 2016 11:10:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{ "ietf-restconf:errors" : {
"error" : [
{
"error-type" : "protocol",
"error-tag" : "invalid-value",
"error-path" : "/example-ops:input/delay",
"error-message" : "Invalid input parameter",
}
]
}
}
3.7. Schema Resource
The server can optionally support retrieval of the YANG modules it
supports. If retrieval is supported, then the "schema" leaf MUST be
present in the associated "module" list entry, defined in [RFC7895].
To retrieve a YANG module, a client first needs to get the URL for
retrieving the schema, which is stored in the "schema" leaf. Note
that there is no required structure for this URL. The URL value
shown below is just an example.
The client might send the following GET request message:
GET /restconf/data/ietf-yang-library:modules-state/\
module=example-jukebox,2016-08-15/schema HTTP/1.1
Host: example.com
Accept: application/yang-data+json
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The server might respond:
HTTP/1.1 200 OK
Date: Thu, 11 Feb 2016 11:10:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"ietf-yang-library:schema" :
"https://example.com/mymodules/example-jukebox/2016-08-15"
}
Next the client needs to retrieve the actual YANG schema.
The client might send the following GET request message:
GET https://example.com/mymodules/example-jukebox/\
2016-08-15 HTTP/1.1
Host: example.com
Accept: application/yang
The server might respond:
HTTP/1.1 200 OK
Date: Thu, 11 Feb 2016 11:10:31 GMT
Server: example-server
Content-Type: application/yang
module example-jukebox {
// contents of YANG module deleted for this example...
}
3.8. Event Stream Resource
An "event stream" resource represents a source for system generated
event notifications. Each stream is created and modified by the
server only. A client can retrieve a stream resource or initiate a
long-poll server sent event stream, using the procedure specified in
Section 6.3.
An event stream functions according to the NETCONF Notifications
specification [RFC5277]. The available streams can be retrieved from
the stream list, which specifies the syntax and semantics of the
stream resources.
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3.9. Errors YANG Data Template
The "errors" YANG data template models a collection of error
information that is sent as the message-body in a server response
message, if an error occurs while processing a request message. It
is not considered as a resource type because no instances can be
retrieved with a GET request.
The "ietf-restconf" YANG module contains the "yang-errors" YANG data
template, that specifies the syntax and semantics of an "errors"
container within a RESTCONF response. RESTCONF error handling
behavior is defined in Section 7.
4. RESTCONF Methods
The RESTCONF protocol uses HTTP methods to identify the CRUD
operations requested for a particular resource.
The following table shows how the RESTCONF operations relate to
NETCONF protocol operations and for the NETCONF
operation, the "nc:operation" attribute.
+----------+-----------------------------------------------+
| RESTCONF | NETCONF |
+----------+-----------------------------------------------+
| OPTIONS | none |
| HEAD | none |
| GET | , |
| POST | (nc:operation="create") |
| POST | invoke an RPC operation |
| PUT | (nc:operation="create/replace") |
| PATCH | (nc:operation="merge") |
| DELETE | (nc:operation="delete") |
+----------+-----------------------------------------------+
CRUD Methods in RESTCONF
The "remove" edit operation attribute for the NETCONF
RPC operation is not supported by the HTTP DELETE method. The
resource must exist or the DELETE method will fail. The PATCH method
is equivalent to a "merge" edit operation when using a plain patch
(see Section 4.6.1); other media-types may provide more granular
control.
Access control mechanisms are used to limit what CRUD operations can
be used. In particular, RESTCONF is compatible with the NETCONF
Access Control Model (NACM) [RFC6536], as there is a specific mapping
between RESTCONF and NETCONF operations. The resource path needs to
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be converted internally by the server to the corresponding YANG
instance-identifier. Using this information, the server can apply
the NACM access control rules to RESTCONF messages.
The server MUST NOT allow any RESTCONF operation for any resources
that the client is not authorized to access.
Implementation of all methods (except PATCH [RFC5789]) are defined in
[RFC7231]. This section defines the RESTCONF protocol usage for each
HTTP method.
4.1. OPTIONS
The OPTIONS method is sent by the client to discover which methods
are supported by the server for a specific resource (e.g., GET, POST,
DELETE, etc.). The server MUST implement this method.
If the PATCH method is supported, then the "Accept-Patch" header
field MUST be supported and returned in the response to the OPTIONS
request, as defined in [RFC5789].
4.2. HEAD
The RESTCONF server MUST support the HEAD method. The HEAD method is
sent by the client to retrieve just the header fields (which contain
the metadata for a resource) that would be returned for the
comparable GET method, without the response message-body. It is
supported for all resources that support the GET method.
The request MUST contain a request URI that contains at least the
root resource. The same query parameters supported by the GET method
are supported by the HEAD method.
The access control behavior is enforced as if the method was GET
instead of HEAD. The server MUST respond the same as if the method
was GET instead of HEAD, except that no response message-body is
included.
4.3. GET
The RESTCONF server MUST support the GET method. The GET method is
sent by the client to retrieve data and metadata for a resource. It
is supported for all resource types, except operation resources. The
request MUST contain a request URI that contains at least the root
resource.
The server MUST NOT return any data resources for which the user does
not have read privileges. If the user is not authorized to read the
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target resource, an error response containing a "401 Unauthorized"
status-line SHOULD be returned. The error-tag value "access-denied"
is returned in this case. A server MAY return a "404 Not Found"
status-line, as described in section 6.5.3 in [RFC7231]. The error-
tag value "invalid-value" is returned in this case.
If the user is authorized to read some but not all of the target
resource, the unauthorized content is omitted from the response
message-body, and the authorized content is returned to the client.
If any content is returned to the client, then the server MUST send a
valid response message-body. More than one element MUST NOT be
returned for XML encoding. If multiple elements are sent in a JSON
message-body, then they MUST be sent as a JSON array. In this case
any timestamp or entity-tag returned in the response MUST be
associated with the first element returned.
If a retrieval request for a data resource representing a YANG leaf-
list or list object identifies more than one instance, and XML
encoding is used in the response, then an error response containing a
"400 Bad Request" status-line MUST be returned by the server. The
error-tag value "invalid-value" is used in this case. Note that a
non-configuration list is not required to defined any keys. In this
case, retrieval of a single list instance is not possible.
If a retrieval request for a data resource represents an instance
that does not exist, then an error response containing a "404 Not
Found" status-line MUST be returned by the server. The error-tag
value "invalid-value" is used in this case.
If the target resource of a retrieval request is for an operation
resource then a "405 Method Not Allowed" status-line MUST be returned
by the server. The error-tag value "operation-not-supported" is used
in this case.
Note that the way that access control is applied to data resources
may not be completely compatible with HTTP caching. The Last-
Modified and ETag header fields maintained for a data resource are
not affected by changes to the access control rules for that data
resource. It is possible for the representation of a data resource
that is visible to a particular client to be changed without
detection via the Last-Modified or ETag values.
Example:
The client might request the response header fields for an XML
representation of the a specific "album" resource:
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GET /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:02:40 GMT
Server: example-server
Content-Type: application/yang-data+xml
Cache-Control: no-cache
ETag: "a74eefc993a2b"
Last-Modified: Mon, 23 Apr 2016 11:02:14 GMT
Wasting Lightjbox:alternative2011
Refer to Appendix D.1 for more resource retrieval examples.
4.4. POST
The RESTCONF server MUST support the POST method. The POST method is
sent by the client to create a data resource or invoke an operation
resource. The server uses the target resource type to determine how
to process the request.
+-----------+------------------------------------------------+
| Type | Description |
+-----------+------------------------------------------------+
| Datastore | Create a top-level configuration data resource |
| Data | Create a configuration data child resource |
| Operation | Invoke an RPC operation |
+-----------+------------------------------------------------+
Resource Types that Support POST
4.4.1. Create Resource Mode
If the target resource type is a datastore or data resource, then the
POST is treated as a request to create a top-level resource or child
resource, respectively. The message-body is expected to contain the
content of a child resource to create within the parent (target
resource). The message-body MUST contain exactly one instance of the
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expected data resource. The data-model for the child tree is the
subtree as defined by YANG for the child resource.
The "insert" Section 4.8.5 and "point" Section 4.8.6 query parameters
MUST be supported by the POST method for datastore and data
resources. These parameters are only allowed if the list or leaf-
list is ordered-by user.
If the POST method succeeds, a "201 Created" status-line is returned
and there is no response message-body. A "Location" header field
identifying the child resource that was created MUST be present in
the response in this case.
If the data resource already exists, then the POST request MUST fail
and a "409 Conflict" status-line MUST be returned. The error-tag
value "resource-denied" is used in this case.
If the user is not authorized to create the target resource, an error
response containing a "403 Forbidden" status-line SHOULD be returned.
The error-tag value "access-denied" is used in this case. A server
MAY return a "404 Not Found" status-line, as described in section
6.5.3 in [RFC7231]. The error-tag value "invalid-value" is used in
this case. All other error responses are handled according to the
procedures defined in Section 7.
Example:
To create a new "jukebox" resource, the client might send:
POST /restconf/data HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{ "example-jukebox:jukebox" : {} }
If the resource is created, the server might respond as follows:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Location: https://example.com/restconf/data/\
example-jukebox:jukebox
Last-Modified: Mon, 23 Apr 2016 17:01:00 GMT
ETag: "b3a3e673be2"
Refer to Appendix D.2.1 for more resource creation examples.
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4.4.2. Invoke Operation Mode
If the target resource type is an operation resource, then the POST
method is treated as a request to invoke that operation. The
message-body (if any) is processed as the operation input parameters.
Refer to Section 3.6 for details on operation resources.
If the POST request succeeds, a "200 OK" status-line is returned if
there is a response message-body, and a "204 No Content" status-line
is returned if there is no response message-body.
If the user is not authorized to invoke the target operation, an
error response containing a "403 Forbidden" status-line is returned
to the client. The error-tag value "access-denied" is used in this
case. All other error responses are handled according to the
procedures defined in Section 7.
Example:
In this example, the client is invoking the "play" operation defined
in the "example-jukebox" YANG module.
A client might send a "play" request as follows:
POST /restconf/operations/example-jukebox:play HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{
"example-jukebox:input" : {
"playlist" : "Foo-One",
"song-number" : 2
}
}
The server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2016 17:50:00 GMT
Server: example-server
4.5. PUT
The RESTCONF server MUST support the PUT method. The PUT method is
sent by the client to create or replace the target data resource. A
request message-body MUST be present, representing the new data
resource, or the server MUST return "400 Bad Request" status-line.
The error-tag value "invalid-value" is used in this case.
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Both the POST and PUT methods can be used to create data resources.
The difference is that for POST, the client does not provide the
resource identifier for the resource that will be created. The
target resource for the POST method for resource creation is the
parent of the new resource. The target resource for the PUT method
for resource creation is the new resource.
The PUT method MUST be supported for data and datastore resources. A
PUT on the datastore resource is used to replace the entire contents
of the datastore. A PUT on a data resource only replaces that data
resource within the datastore.
The "insert" (Section 4.8.5) and "point" (Section 4.8.6) query
parameters MUST be supported by the PUT method for data resources.
These parameters are only allowed if the list or leaf-list is
ordered-by user.
Consistent with [RFC7231], if the PUT request creates a new resource,
a "201 Created" status-line is returned. If an existing resource is
modified, a "204 No Content" status-line is returned.
If the user is not authorized to create or replace the target
resource an error response containing a "403 Forbidden" status-line
SHOULD be returned. The error-tag value "access-denied" is used in
this case.
A server MAY return a "404 Not Found" status-line, as
described in section 6.5.3 in ^RFC7231^.
The error-tag value "invalid-value" is used in this case.
All other error responses are handled according to
the procedures defined in ^error-reporting^.
If the target resource represents a YANG leaf-list, then the PUT
method MUST NOT change the value of the leaf-list instance.
If the target resource represents a YANG list instance, then the key
leaf values in message-body representation MUST be the same as the
key leaf values in the request URI. The PUT method MUST NOT be used
to change the key leaf values for a data resource instance.
Example:
An "album" child resource defined in the "example-jukebox" YANG
module is replaced or created if it does not already exist.
To replace the "album" resource contents, the client might send as
follows:
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PUT /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{
"example-jukebox:album" : [
{
"name" : "Wasting Light",
"genre" : "example-jukebox:alternative",
"year" : 2011
}
]
}
If the resource is updated, the server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2016 17:04:00 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2016 17:04:00 GMT
ETag: "b27480aeda4c"
The same request is shown here using XML encoding:
PUT /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
Wasting Lightjbox:alternative2011
4.6. PATCH
The RESTCONF server MUST support the PATCH method. RESTCONF uses the
HTTP PATCH method defined in [RFC5789] to provide an extensible
framework for resource patching mechanisms. It is optional to
implement by the server. Each patch mechanism needs a unique media
type. Zero or more patch media types MAY be supported by the server.
The media types supported by a server can be discovered by the client
by sending an OPTIONS request, and examining the Accept-Patch header
field in the response. (see Section 4.1).
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This document defines one patch mechanism (Section 4.6.1). Another
patch mechanism, the YANG PATCH mechanism, is defined in
[I-D.ietf-netconf-yang-patch]. Other patch mechanisms may be defined
by future specifications.
If the target resource instance does not exist, the server MUST NOT
create it.
If the PATCH request succeeds, a "200 OK" status-line is returned if
there is a message-body, and "204 No Content" is returned if no
response message-body is sent.
If the user is not authorized to alter the target resource an error
response containing a "403 Forbidden" status-line SHOULD be returned.
A server MAY return a "404 Not Found" status-line, as described in
section 6.5.3 in [RFC7231]. The error-tag value "invalid-value" is
used in this case. All other error responses are handled according
to the procedures defined in Section 7.
4.6.1. Plain Patch
The plain patch mechanism merges the contents of the message-body
with the target resource. The message-body for a plain patch MUST be
present and MUST be represented by the media type "application/
yang-data+xml" or "application/yang-data+json".
Plain patch can be used to create or update, but not delete, a child
resource within the target resource. Please see
[I-D.ietf-netconf-yang-patch] for an alternate media-type supporting
the ability to delete child resources. The YANG Patch Media Type
allows multiple sub-operations (e.g., merge, delete) within a single
PATCH method.
If the target resource represents a YANG leaf-list, then the PATCH
method MUST NOT change the value of the leaf-list instance.
If the target resource represents a YANG list instance, then the key
leaf values in message-body representation MUST be the same as the
key leaf values in the request URI. The PATCH method MUST NOT be
used to change the key leaf values for a data resource instance.
After the plain patch is processed by the server. a response will be
returned to the client, as specified in Section 4.6.
Example:
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To replace just the "year" field in the "album" resource (instead of
replacing the entire resource with the PUT method), the client might
send a plain patch as follows.
PATCH /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light HTTP/1.1
Host: example.com
If-Match: "b8389233a4c"
Content-Type: application/yang-data+xml
2011
If the field is updated, the server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2016 17:49:30 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2016 17:49:30 GMT
ETag: "b2788923da4c"
4.7. DELETE
The RESTCONF server MUST support the DELETE method. The DELETE
method is used to delete the target resource. If the DELETE request
succeeds, a "204 No Content" status-line is returned.
If the user is not authorized to delete the target resource then an
error response containing a "403 Forbidden" status-line SHOULD be
returned. The error-tag value "access-denied" is returned in this
case. A server MAY return a "404 Not Found" status-line, as
described in section 6.5.3 in [RFC7231]. The error-tag value
"invalid-value" is returned in this case. All other error responses
are handled according to the procedures defined in Section 7.
If the target resource represents a configuration leaf-list or list
data node, then it MUST represent a single YANG leaf-list or list
instance. The server MUST NOT use the DELETE method to delete more
than one such instance.
Example:
To delete the "album" resource with the key "Wasting Light", the
client might send:
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DELETE /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light HTTP/1.1
Host: example.com
If the resource is deleted, the server might respond:
HTTP/1.1 204 No Content
Date: Mon, 23 Apr 2016 17:49:40 GMT
Server: example-server
4.8. Query Parameters
Each RESTCONF operation allows zero or more query parameters to be
present in the request URI. The specific parameters that are allowed
depends on the resource type, and sometimes the specific target
resource used, in the request.
o Query parameters can be given in any order.
o Each parameter can appear at most once in a request URI.
o If more than one instance of a query parameter is present, then a
"400 Bad Request" status-line MUST be returned by the server. The
error-tag value "invalid-value" is returned in this case.
o A default value may apply if the parameter is missing.
o Query parameter names and values are case-sensitive
o A server MUST return an error with a '400 Bad Request' status-line
if a query parameter is unexpected. The error-tag value
"invalid-value" is returned in this case.
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+---------------+---------+-----------------------------------------+
| Name | Methods | Description |
+---------------+---------+-----------------------------------------+
| content | GET, | Select config and/or non-config data |
| | HEAD | resources |
| depth | GET, | Request limited sub-tree depth in the |
| | HEAD | reply content |
| fields | GET, | Request a subset of the target resource |
| | HEAD | contents |
| filter | GET, | Boolean notification filter for event |
| | HEAD | stream resources |
| insert | POST, | Insertion mode for ordered-by user data |
| | PUT | resources |
| point | POST, | Insertion point for ordered-by user |
| | PUT | data resources |
| start-time | GET, | Replay buffer start time for event |
| | HEAD | stream resources |
| stop-time | GET, | Replay buffer stop time for event |
| | HEAD | stream resources |
| with-defaults | GET, | Control retrieval of default values |
| | HEAD | |
+---------------+---------+-----------------------------------------+
RESTCONF Query Parameters
Refer to Appendix D.3 for examples of query parameter usage.
If vendors define additional query parameters, they SHOULD use a
prefix (such as the enterprise or organization name) for query
parameter names in order to avoid collisions with other parameters.
4.8.1. The "content" Query Parameter
The "content" parameter controls how descendant nodes of the
requested data nodes will be processed in the reply.
The allowed values are:
+-----------+-----------------------------------------------------+
| Value | Description |
+-----------+-----------------------------------------------------+
| config | Return only configuration descendant data nodes |
| nonconfig | Return only non-configuration descendant data nodes |
| all | Return all descendant data nodes |
+-----------+-----------------------------------------------------+
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This parameter is only allowed for GET methods on datastore and data
resources. A "400 Bad Request" status-line is returned if used for
other methods or resource types.
If this query parameter is not present, the default value is "all".
This query parameter MUST be supported by the server.
4.8.2. The "depth" Query Parameter
The "depth" parameter is used to limit the depth of subtrees returned
by the server. Data nodes with a depth value greater than the
"depth" parameter are not returned in a response for a GET method.
The requested data node has a depth level of '1'. If the "fields"
parameter (Section 4.8.3) is used to select descendant data nodes,
then these nodes and all their ancestor nodes have a depth value of
1. (This has the effect of including the nodes specified by the
fields, even if the "depth" value is less than the actual depth level
of the specified fields.) Any other child node has a depth value
that is 1 greater than its parent.
The value of the "depth" parameter is either an integer between 1 and
65535, or the string "unbounded". "unbounded" is the default.
This parameter is only allowed for GET methods on API, datastore, and
data resources. A "400 Bad Request" status-line is returned if it
used for other methods or resource types.
By default, the server will include all sub-resources within a
retrieved resource, which have the same resource type as the
requested resource. The exception is the datastore resource. If
this resource type is retrieved then by default the datastore and all
child data resources are returned.
If the "depth" query parameter URI is listed in the "capability"
leaf-list in Section 9.3, then the server supports the "depth" query
parameter.
4.8.3. The "fields" Query Parameter
The "fields" query parameter is used to optionally identify data
nodes within the target resource to be retrieved in a GET method.
The client can use this parameter to retrieve a subset of all nodes
in a resource.
The server will return a message-body representing the target
resource, with descendant nodes pruned as specified in the
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"fields-expr" value. The server does not return a set of separate
sub-resources.
A value of the "fields" query parameter matches the following rule:
fields-expr = path '(' fields-expr ')' /
path ';' fields-expr /
path
path = api-identifier [ '/' path ]
"api-identifier" is defined in Section 3.5.3.1.
";" is used to select multiple nodes. For example, to retrieve only
the "genre" and "year" of an album, use: "fields=genre;year".
Parentheses are used to specify sub-selectors of a node. Note that
there is no path separator character '/' between a "path" field and
left parenthesis character '('.
For example, assume the target resource is the "album" list. To
retrieve only the "label" and "catalogue-number" of the "admin"
container within an album, use:
"fields=admin(label;catalogue-number)".
"/" is used in a path to retrieve a child node of a node. For
example, to retrieve only the "label" of an album, use:
"fields=admin/label".
This parameter is only allowed for GET methods on api, datastore, and
data resources. A "400 Bad Request" status-line is returned if used
for other methods or resource types.
If the "fields" query parameter URI is listed in the "capability"
leaf-list in Section 9.3, then the server supports the "fields"
parameter.
4.8.4. The "filter" Query Parameter
The "filter" parameter is used to indicate which subset of all
possible events are of interest. If not present, all events not
precluded by other parameters will be sent.
This parameter is only allowed for GET methods on an event stream
resource. A "400 Bad Request" status-line is returned if used for
other methods or resource types.
The format of this parameter is an XPath 1.0 expression, and is
evaluated in the following context:
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o The set of namespace declarations is the set of prefix and
namespace pairs for all supported YANG modules, where the prefix
is the YANG module name, and the namespace is as defined by the
"namespace" statement in the YANG module.
o The function library is the core function library defined in XPath
1.0, plus any functions defined by the data model.
o The set of variable bindings is empty.
o The context node is the root node.
The filter is used as defined in [RFC5277], Section 3.6. If the
boolean result of the expression is true when applied to the
conceptual "notification" document root, then the event notification
is delivered to the client.
If the "filter" query parameter URI is listed in the "capability"
leaf-list in Section 9.3, then the server supports the "filter" query
parameter.
4.8.5. The "insert" Query Parameter
The "insert" parameter is used to specify how a resource should be
inserted within a ordered-by user list.
The allowed values are:
+--------+----------------------------------------------------------+
| Value | Description |
+--------+----------------------------------------------------------+
| first | Insert the new data as the new first entry. |
| last | Insert the new data as the new last entry. |
| before | Insert the new data before the insertion point, as |
| | specified by the value of the "point" parameter. |
| after | Insert the new data after the insertion point, as |
| | specified by the value of the "point" parameter. |
+--------+----------------------------------------------------------+
The default value is "last".
This parameter is only supported for the POST and PUT methods. It is
also only supported if the target resource is a data resource, and
that data represents a YANG list or leaf-list that is ordered-by
user.
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If the values "before" or "after" are used, then a "point" query
parameter for the insertion parameter MUST also be present, or a "400
Bad Request" status-line is returned.
The "insert" query parameter MUST be supported by the server.
4.8.6. The "point" Query Parameter
The "point" parameter is used to specify the insertion point for a
data resource that is being created or moved within an ordered-by
user list or leaf-list.
The value of the "point" parameter is a string that identifies the
path to the insertion point object. The format is the same as a
target resource URI string.
This parameter is only supported for the POST and PUT methods. It is
also only supported if the target resource is a data resource, and
that data represents a YANG list or leaf-list that is ordered-by
user.
If the "insert" query parameter is not present, or has a value other
than "before" or "after", then a "400 Bad Request" status-line is
returned.
This parameter contains the instance identifier of the resource to be
used as the insertion point for a POST or PUT method.
The "point" query parameter MUST be supported by the server.
4.8.7. The "start-time" Query Parameter
The "start-time" parameter is used to trigger the notification replay
feature defined in [RFC5277] and indicate that the replay should
start at the time specified. If the stream does not support replay,
per the "replay-support" attribute returned by stream list entry for
the stream resource, then the server MUST return a "400 Bad Request"
status-line.
The value of the "start-time" parameter is of type "date-and-time",
defined in the "ietf-yang" YANG module [RFC6991].
This parameter is only allowed for GET methods on a text/event-stream
data resource. A "400 Bad Request" status-line is returned if used
for other methods or resource types.
If this parameter is not present, then a replay subscription is not
being requested. It is not valid to specify start times that are
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later than the current time. If the value specified is earlier than
the log can support, the replay will begin with the earliest
available notification. A client can obtain a server's current time
by examining the "Date" header field that the server returns in
response messages, according to [RFC7231].
If this query parameter is supported by the server, then the "replay"
query parameter URI MUST be listed in the "capability" leaf-list in
Section 9.3, anf the "stop-time" query parameter MUST also be
supported by the server.
If the "replay-support" leaf has the value 'true' in the "stream"
entry (defined in Section 9.3) then the server MUST support the
"start-time" and "stop-time" query parameters for that stream.
4.8.8. The "stop-time" Query Parameter
The "stop-time" parameter is used with the replay feature to indicate
the newest notifications of interest. This parameter MUST be used
with and have a value later than the "start-time" parameter.
The value of the "stop-time" parameter is of type "date-and-time",
defined in the "ietf-yang" YANG module [RFC6991].
This parameter is only allowed for GET methods on a text/event-stream
data resource. A "400 Bad Request" status-line is returned if used
for other methods or resource types.
If this parameter is not present, the notifications will continue
until the subscription is terminated. Values in the future are
valid.
If this query parameter is supported by the server, then the "replay"
query parameter URI MUST be listed in the "capability" leaf-list in
Section 9.3, and the "start-time" query parameter MUST also be
supported by the server.
If the "replay-support" leaf is present in the "stream" entry
(defined in Section 9.3) then the server MUST support the
"start-time" and "stop-time" query parameters for that stream.
4.8.9. The "with-defaults" Query Parameter
The "with-defaults" parameter is used to specify how information
about default data nodes should be returned in response to GET
requests on data resources.
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If the server supports this capability, then it MUST implement the
behavior in Section 4.5.1 of [RFC6243], except applied to the
RESTCONF GET operation, instead of the NETCONF operations.
+-------------------+-----------------------------------------------+
| Value | Description |
+-------------------+-----------------------------------------------+
| report-all | All data nodes are reported |
| trim | Data nodes set to the YANG default are not |
| | reported |
| explicit | Data nodes set to the YANG default by the |
| | client are reported |
| report-all-tagged | All data nodes are reported and defaults are |
| | tagged |
+-------------------+-----------------------------------------------+
If the "with-defaults" parameter is set to "report-all" then the
server MUST adhere to the defaults reporting behavior defined in
Section 3.1 of [RFC6243].
If the "with-defaults" parameter is set to "trim" then the server
MUST adhere to the defaults reporting behavior defined in Section 3.2
of [RFC6243].
If the "with-defaults" parameter is set to "explicit" then the server
MUST adhere to the defaults reporting behavior defined in Section 3.3
of [RFC6243].
If the "with-defaults" parameter is set to "report-all-tagged" then
the server MUST adhere to the defaults reporting behavior defined in
Section 3.4 of [RFC6243]. Metadata is reported by the server as
specified in Section 5.3. The XML encoding for the "default"
attribute sent by the server for default nodes is defined in section
6 of [RFC6243]. The JSON encoding for the "default" attribute MUST
use the same values as defined in [RFC6243], but encoded according to
the rules in [RFC7952]. The module name "ietf-netconf-with-defaults"
MUST be used for the "default" attribute.
If the "with-defaults" parameter is not present then the server MUST
adhere to the defaults reporting behavior defined in its "basic-mode"
parameter for the "defaults" protocol capability URI, defined in
Section 9.1.2.
If the server includes the "with-defaults" query parameter URI in the
"capability" leaf-list in Section 9.3, then the "with-defaults" query
parameter MUST be supported.
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Since the server does not report the "also-supported" parameter as
described in section 4.3 of [RFC6243], it is possible that some
values for the "with-defaults" parameter will not be supported. If
the server does not support the requested value of the
"with-defaults" parameter, the server MUST return a response with a
"400 Bad Request" status-line. The error-tag value "invalid-value"
is used in this case.
5. Messages
The RESTCONF protocol uses HTTP messages. A single HTTP message
corresponds to a single protocol method. Most messages can perform a
single task on a single resource, such as retrieving a resource or
editing a resource. The exception is the PATCH method, which allows
multiple datastore edits within a single message.
5.1. Request URI Structure
Resources are represented with URIs following the structure for
generic URIs in [RFC3986].
A RESTCONF operation is derived from the HTTP method and the request
URI, using the following conceptual fields:
//?
^ ^ ^ ^
| | | |
method entry resource query
M M O O
M=mandatory, O=optional
where:
is the HTTP method
is the RESTCONF root resource
is the Target Resource URI
is the query parameter list
o method: the HTTP method identifying the RESTCONF operation
requested by the client, to act upon the target resource specified
in the request URI. RESTCONF operation details are described in
Section 4.
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o entry: the root of the RESTCONF API configured on this HTTP
server, discovered by getting the "/.well-known/host-meta"
resource, as described in Section 3.1.
o resource: the path expression identifying the resource that is
being accessed by the RESTCONF operation. If this field is not
present, then the target resource is the API itself, represented
by the YANG data template named "yang-api", found in Section 8.
o query: the set of parameters associated with the RESTCONF message,
as defined in section 3.4 of [RFC3986]. RESTCONF parameters have
the familiar form of "name=value" pairs. Most query parameters
are optional to implement by the server and optional to use by the
client. Each optional query parameter is identified by a URI.
The server MUST list the optional query parameter URIs it supports
in the "capabilities" list defined in Section 9.3.
There is a specific set of parameters defined, although the server
MAY choose to support query parameters not defined in this document.
The contents of the any query parameter value MUST be encoded
according to [RFC3986], Section 3.4. Any reserved characters MUST be
percent-encoded, according to [RFC3986], section 2.1 and 2.5.
Note that the fragment component not used by the RESTCONF protocol.
The fragment is excluded from the target URI by a server, as
described in section 5.1 of [RFC7230].
When new resources are created by the client, a "Location" header
field is returned, which identifies the path of the newly created
resource. The client uses this exact path identifier to access the
resource once it has been created.
The "target" of a RESTCONF operation is a resource. The "path" field
in the request URI represents the target resource for the RESTCONF
operation.
Refer to Appendix D for examples of RESTCONF Request URIs.
5.2. Message Encoding
RESTCONF messages are encoded in HTTP according to [RFC7230]. The
"utf-8" character set is used for all messages. RESTCONF message
content is sent in the HTTP message-body.
Content is encoded in either JSON or XML format. A server MUST
support one of either XML or JSON encoding. A server MAY support
both XML and JSON encoding. XML encoding rules for data nodes are
defined in [RFC7950]. The same encoding rules are used for all XML
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content. JSON encoding rules are defined in [RFC7951]. Additional
JSON encoding rules for metadata are defined in [RFC7952]. This
encoding is valid JSON, but also has special encoding rules to
identify module namespaces and provide consistent type processing of
YANG data.
Request input content encoding format is identified with the Content-
Type header field. This field MUST be present if a message-body is
sent by the client.
The server MUST support the "Accept" header field and "406 Not
Acceptable" status-line, as defined in [RFC7231]. The response
output content encoding formats that the client will accept are
identified with the Accept header field in the request. If it is not
specified, the request input encoding format SHOULD be used, or the
server MAY choose any supported content encoding format.
If there was no request input, then the default output encoding is
XML or JSON, depending on server preference. File extensions encoded
in the request are not used to identify format encoding.
A client can determine if the RESTCONF server supports an encoding
format by sending a request using a specific format in the Content-
Type and/or Accept header field. If the server does not support the
requested input encoding for a request, then it MUST return an error
response with a '415 Unsupported Media Type' status-line. If the
server does not support any of the requested output encodings for a
request, then it MUST return an error response with a '406 Not
Acceptable' status-line.
5.3. RESTCONF Metadata
The RESTCONF protocol needs support retrieval of the same metadata
that is used in the NETCONF protocol. Information about default
leafs, last-modified timestamps, etc. are commonly used to annotate
representations of the datastore contents.
With the XML encoding, the metadata is encoded as attributes in XML,
according to section 3.3 of [W3C.REC-xml-20081126]. With the JSON
encoding, the metadata is encoded as specified in [RFC7952].
The following examples are based on the example in Appendix D.3.9.
The "report-all-tagged" mode for the "with-defaults" query parameter
requires that a "default" attribute be returned for default nodes.
This example shows that attribute for the "mtu" leaf .
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5.3.1. XML Metadata Encoding Example
GET /restconf/data/interfaces/interface=eth1
?with-defaults=report-all-tagged HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might respond as follows.
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Content-Type: application/yang-data+xml
eth11500up
5.3.2. JSON Metadata Encoding Example
Note that RFC 6243 defines the "default" attribute with XSD, not
YANG, so the YANG module name has to be assigned instead of derived
from the YANG module. The value "ietf-netconf-with-defaults" is
assigned for JSON metadata encoding.
GET /restconf/data/interfaces/interface=eth1\
?with-defaults=report-all-tagged HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows.
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"example:interface" : [
{
"name" : "eth1",
"mtu" : 1500,
"@mtu" : {
"ietf-netconf-with-defaults:default" : true
},
"status" : "up"
}
]
}
5.4. Return Status
Each message represents some sort of resource access. An HTTP
"status-line" header field is returned for each request. If a "4xx"
range status code is returned in the status-line, then the error
information SHOULD be returned in the response, according to the
format defined in Section 7.1. If a "5xx" range status code is
returned in the status-line, then the error information MAY be
returned in the response, according to the format defined in
Section 7.1. If a 1xx, 2xx, or 3xx range status code is returned in
the status-line, then error information MUST NOT be returned in the
response, since these ranges do not represent error conditions.
5.5. Message Caching
Since the datastore contents change at unpredictable times, responses
from a RESTCONF server generally SHOULD NOT be cached.
The server SHOULD include a "Cache-Control" header field in every
response that specifies whether the response should be cached.
Instead of relying on HTTP caching, the client SHOULD track the
"ETag" and/or "Last-Modified" header fields returned by the server
for the datastore resource (or data resource if the server supports
it). A retrieval request for a resource can include the
"If-None-Match" and/or "If-Modified-Since" header fields, which will
cause the server to return a "304 Not Modified" status-line if the
resource has not changed. The client MAY use the HEAD method to
retrieve just the message header fields, which SHOULD include the
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"ETag" and "Last-Modified" header fields, if this metadata is
maintained for the target resource.
Note that the way that access control is applied to data resources
the values in the Last-Modified and ETag headers maintained for a
data resource may not be reliable, as described in Section 4.3.
6. Notifications
The RESTCONF protocol supports YANG-defined event notifications. The
solution preserves aspects of NETCONF Event Notifications [RFC5277]
while utilizing the Server-Sent Events [W3C.REC-eventsource-20150203]
transport strategy.
6.1. Server Support
A RESTCONF server MAY support RESTCONF notifications. Clients may
determine if a server supports RESTCONF notifications by using the
HTTP method OPTIONS, HEAD, or GET on the stream list. The server
does not support RESTCONF notifications if an HTTP error code is
returned (e.g., "404 Not Found" status-line).
6.2. Event Streams
A RESTCONF server that supports notifications will populate a stream
resource for each notification delivery service access point. A
RESTCONF client can retrieve the list of supported event streams from
a RESTCONF server using the GET method on the stream list.
The "restconf-state/streams" container definition in the
"ietf-restconf-monitoring" module (defined in Section 9.3) is used to
specify the structure and syntax of the conceptual child resources
within the "streams" resource.
For example:
The client might send the following request:
GET /restconf/data/ietf-restconf-monitoring:restconf-state/\
streams HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might send the following response:
HTTP/1.1 200 OK
Content-Type: application/yang-data+xml
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NETCONFdefault NETCONF event streamtrue\
2007-07-08T00:00:00Z\
xmlhttps://example.com/streams/NETCONF\
jsonhttps://example.com/streams/NETCONF-JSON\
SNMPSNMP notificationsfalsexmlhttps://example.com/streams/SNMPsyslog-criticalCritical and higher severitytrue
2007-07-01T00:00:00Z
xml\
https://example.com/streams/syslog-critical\
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6.3. Subscribing to Receive Notifications
RESTCONF clients can determine the URL for the subscription resource
(to receive notifications) by sending an HTTP GET request for the
"location" leaf with the stream list entry. The value returned by
the server can be used for the actual notification subscription.
The client will send an HTTP GET request for the URL returned by the
server with the "Accept" type "text/event-stream".
The server will treat the connection as an event stream, using the
Server Sent Events [W3C.REC-eventsource-20150203] transport strategy.
The server MAY support query parameters for a GET method on this
resource. These parameters are specific to each event stream.
For example:
The client might send the following request:
GET /restconf/data/ietf-restconf-monitoring:restconf-state/\
streams/stream=NETCONF/access=xml/location HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might send the following response:
HTTP/1.1 200 OK
Content-Type: application/yang-data+xml
\
https://example.com/streams/NETCONF\
The RESTCONF client can then use this URL value to start monitoring
the event stream:
GET /streams/NETCONF HTTP/1.1
Host: example.com
Accept: text/event-stream
Cache-Control: no-cache
Connection: keep-alive
A RESTCONF client MAY request that the server compress the events
using the HTTP header field "Accept-Encoding". For instance:
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GET /streams/NETCONF HTTP/1.1
Host: example.com
Accept: text/event-stream
Cache-Control: no-cache
Connection: keep-alive
Accept-Encoding: gzip, deflate
6.3.1. NETCONF Event Stream
The server SHOULD support the "NETCONF" event stream defined in
section 3.2.3 of [RFC5277]. The notification messages for this
stream are encoded in XML.
The server MAY support additional streams which represent the
semantic content of the NETCONF event stream, but using a
representation with a different media type.
The server MAY support the "start-time", "stop-time", and "filter"
query parameters, defined in Section 4.8. Refer to Appendix D.3.6
for filter parameter examples.
6.4. Receiving Event Notifications
RESTCONF notifications are encoded according to the definition of the
event stream.
The structure of the event data is based on the "notification"
element definition in Section 4 of [RFC5277]. It MUST conform to the
schema for the "notification" element in Section 4 of [RFC5277] using
the XML namespace as defined in the XSD as follows:
urn:ietf:params:xml:ns:netconf:notification:1.0
For JSON encoding purposes, the module name for the "notification"
element is "ietf-restconf".
Two child nodes within the "notification" container are expected,
representing the event time and the event payload. The "eventTime"
node is defined within the same XML namespace as the "notification"
element. It is defined to be within the "ietf-restconf" module
namespace for JSON encoding purposes.
The name and namespace of the payload element are determined by the
YANG module containing the notification-stmt representing the
notification message.
In the following example, the YANG module "example-mod" is used:
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module example-mod {
namespace "http://example.com/event/1.0";
prefix ex;
notification event {
leaf event-class { type string; }
container reporting-entity {
leaf card { type string; }
}
leaf severity { type string; }
}
}
An example SSE event notification encoded using XML:
data:
data: 2013-12-21T00:01:00Z
data:
data: fault
data:
data: Ethernet0
data:
data: major
data:
data:
An example SSE event notification encoded using JSON:
data: {
data: "ietf-restconf:notification" : {
data: "eventTime" : "2013-12-21T00:01:00Z",
data: "example-mod:event" : {
data: "event-class" : "fault",
data: "reporting-entity" : { "card" : "Ethernet0" },
data: "severity" : "major"
data: }
data: }
data: }
Alternatively, since neither XML nor JSON are whitespace sensitive,
the above messages can be encoded onto a single line. For example:
For example:
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XML:
data: 2013-12-21T00:01:00ZfaultEthernet0\
major
JSON:
data: {"ietf-restconf:notification":{"eventTime":"2013-12-21\
T00:01:00Z","example-mod:event":{"event-class": "fault","repor\
tingEntity":{"card":"Ethernet0"},"severity":"major"}}}
The SSE specifications supports the following additional fields:
event, id and retry. A RESTCONF server MAY send the "retry" field
and, if it does, RESTCONF clients SHOULD use it. A RESTCONF server
SHOULD NOT send the "event" or "id" fields, as there are no
meaningful values that could be used for them that would not be
redundant to the contents of the notification itself. RESTCONF
servers that do not send the "id" field also do not need to support
the HTTP header field "Last-Event-Id". RESTCONF servers that do send
the "id" field SHOULD support the "start-time" query parameter as the
preferred means for a client to specify where to restart the event
stream.
7. Error Reporting
HTTP status codes are used to report success or failure for RESTCONF
operations. The error information that NETCONF error responses
contain in the element is adapted for use in RESTCONF,
and an data tree information is returned for "4xx" and "5xx"
class of status codes.
Since an operation resource is defined with a YANG "rpc" statement,
and an action is defined with a YANG "action" statement, a mapping
from the NETCONF value to the HTTP status code is needed.
The specific error-tag and response code to use are data-model-
specific and might be contained in the YANG "description" statement
for the "action" or "rpc" statement.
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+-------------------------+-----------------+
| error-tag | status code |
+-------------------------+-----------------+
| in-use | 409 |
| invalid-value | 400, 404 or 406 |
| (request) too-big | 413 |
| (response) too-big | 400 |
| missing-attribute | 400 |
| bad-attribute | 400 |
| unknown-attribute | 400 |
| bad-element | 400 |
| unknown-element | 400 |
| unknown-namespace | 400 |
| access-denied | 401, 403 |
| lock-denied | 409 |
| resource-denied | 409 |
| rollback-failed | 500 |
| data-exists | 409 |
| data-missing | 409 |
| operation-not-supported | 405 or 501 |
| operation-failed | 412 or 500 |
| partial-operation | 500 |
| malformed-message | 400 |
+-------------------------+-----------------+
Mapping from error-tag to status code
7.1. Error Response Message
When an error occurs for a request message on any resource type, and
the status code that will be returned is in the "4xx" range (except
for status code "403 Forbidden"), then the server SHOULD send a
response message-body containing the information described by the
"yang-errors" YANG data template within the "ietf-restconf" module,
found in Section 8. The Content-Type of this response message MUST
be "application/yang-data", plus optionally a structured syntax name
suffix.
The client SHOULD specify the desired encoding(s) for response
messages by specifying the appropriate media-type(s) in the Accept
header. If the client did not specify an Accept header, then the
same structured syntax name suffix used in the request message SHOULD
be used, or the server MAY choose any supported message encoding
format. If there is no request message the server MUST select
"application/yang-data+xml" or "application/yang-data+json",
depending on server preference. All of the examples in this
document, except for the one below, assume that XML encoding will be
returned if there is an error.
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YANG Tree Diagram for data:
+---- errors
+---- error*
+---- error-type enumeration
+---- error-tag string
+---- error-app-tag? string
+---- error-path? instance-identifier
+---- error-message? string
+---- error-info?
The semantics and syntax for RESTCONF error messages are defined with
the "yang-errors" YANG data template extension, found in Section 8.
Examples:
The following example shows an error returned for an "lock-denied"
error that can occur if a NETCONF client has locked a datastore. The
RESTCONF client is attempting to delete a data resource. Note that
an Accept header field is used to specify the desired encoding for
the error message. There would be no response message-body content
if this operation was successful.
DELETE /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
HTTP/1.1 409 Conflict
Date: Mon, 23 Apr 2016 17:11:00 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"ietf-restconf:errors" : {
"error" : [
{
"error-type" : "protocol",
"error-tag" : "lock-denied",
"error-message" : "Lock failed, lock already held"
}
]
}
}
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The following example shows an error returned for a "data-exists"
error on a data resource. The "jukebox" resource already exists so
it cannot be created.
The client might send:
POST /restconf/data/example-jukebox:jukebox HTTP/1.1
Host: example.com
The server might respond:
HTTP/1.1 409 Conflict
Date: Mon, 23 Apr 2016 17:11:00 GMT
Server: example-server
Content-Type: application/yang-data+xml
protocoldata-exists\
/rc:restconf/rc:data/jbox:jukebox
Data already exists, cannot create new resource
8. RESTCONF Module
The "ietf-restconf" module defines conceptual definitions within an
extension and two groupings, which are not meant to be implemented as
datastore contents by a server. E.g., the "restconf" container is
not intended to be implemented as a top-level data node (under the
"/restconf/data" URI).
Note that the "ietf-restconf" module does not have any protocol-
accessible objects, so no YANG tree diagram is shown.
RFC Ed.: update the date below with the date of RFC publication and
remove this note.
file "ietf-restconf@2016-08-15.yang"
module ietf-restconf {
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yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-restconf";
prefix "rc";
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web:
WG List:
Author: Andy Bierman
Author: Martin Bjorklund
Author: Kent Watsen
";
description
"This module contains conceptual YANG specifications
for basic RESTCONF media type definitions used in
RESTCONF protocol messages.
Note that the YANG definitions within this module do not
represent configuration data of any kind.
The 'restconf-media-type' YANG extension statement
provides a normative syntax for XML and JSON message
encoding purposes.
Copyright (c) 2016 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
// RFC Ed.: remove this note
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// Note: extracted from draft-ietf-netconf-restconf-17.txt
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision 2016-08-15 {
description
"Initial revision.";
reference
"RFC XXXX: RESTCONF Protocol.";
}
extension yang-data {
argument name {
yin-element true;
}
description
"This extension is used to specify a YANG data template which
represents conceptual data defined in YANG. It is
intended to describe hierarchical data independent of
protocol context or specific message encoding format.
Data definition statements within a yang-data extension
specify the generic syntax for the specific YANG data
template, whose name is the argument of the yang-data
extension statement.
Note that this extension does not define a media-type.
A specification using this extension MUST specify the
message encoding rules, including the content media type.
The mandatory 'name' parameter value identifies the YANG
data template that is being defined. It contains the
template name.
This extension is ignored unless it appears as a top-level
statement. It MUST contain data definition statements
that result in exactly one container data node definition.
An instance of a YANG data template can thus be translated
into an XML instance document, whose top-level element
corresponds to the top-level container.
The module name and namespace value for the YANG module using
the extension statement is assigned to instance document data
conforming to the data definition statements within
this extension.
The sub-statements of this extension MUST follow the
'data-def-stmt' rule in the YANG ABNF.
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The XPath document root is the extension statement itself,
such that the child nodes of the document root are
represented by the data-def-stmt sub-statements within
this extension. This conceptual document is the context
for the following YANG statements:
- must-stmt
- when-stmt
- path-stmt
- min-elements-stmt
- max-elements-stmt
- mandatory-stmt
- unique-stmt
- ordered-by
- instance-identifier data type
The following data-def-stmt sub-statements are constrained
when used within a yang-data-resource extension statement.
- The list-stmt is not required to have a key-stmt defined.
- The if-feature-stmt is ignored if present.
- The config-stmt is ignored if present.
- The available identity values for any 'identityref'
leaf or leaf-list nodes is limited to the module
containing this extension statement, and the modules
imported into that module.
";
}
rc:yang-data yang-errors {
uses errors;
}
rc:yang-data yang-api {
uses restconf;
}
grouping errors {
description
"A grouping that contains a YANG container
representing the syntax and semantics of a
YANG Patch errors report within a response message.";
container errors {
description
"Represents an error report returned by the server if
a request results in an error.";
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list error {
description
"An entry containing information about one
specific error that occurred while processing
a RESTCONF request.";
reference "RFC 6241, Section 4.3";
leaf error-type {
type enumeration {
enum transport {
description "The transport layer";
}
enum rpc {
description "The rpc or notification layer";
}
enum protocol {
description "The protocol operation layer";
}
enum application {
description "The server application layer";
}
}
mandatory true;
description
"The protocol layer where the error occurred.";
}
leaf error-tag {
type string;
mandatory true;
description
"The enumerated error tag.";
}
leaf error-app-tag {
type string;
description
"The application-specific error tag.";
}
leaf error-path {
type instance-identifier;
description
"The YANG instance identifier associated
with the error node.";
}
leaf error-message {
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type string;
description
"A message describing the error.";
}
anydata error-info {
description
"This anydata value MUST represent a container with
zero or more data nodes representing additional
error information.";
}
}
}
}
grouping restconf {
description
"Conceptual grouping representing the RESTCONF
root resource.";
container restconf {
description
"Conceptual container representing the RESTCONF
root resource.";
container data {
description
"Container representing the datastore resource.
Represents the conceptual root of all state data
and configuration data supported by the server.
The child nodes of this container can be any data
resource which are defined as top-level data nodes
from the YANG modules advertised by the server in
the ietf-yang-library module.";
}
container operations {
description
"Container for all operation resources.
Each resource is represented as an empty leaf with the
name of the RPC operation from the YANG rpc statement.
For example, the 'system-restart' RPC operation defined
in the 'ietf-system' module would be represented as
an empty leaf in the 'ietf-system' namespace. This is
a conceptual leaf, and will not actually be found in
the module:
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module ietf-system {
leaf system-reset {
type empty;
}
}
To invoke the 'system-restart' RPC operation:
POST /restconf/operations/ietf-system:system-restart
To discover the RPC operations supported by the server:
GET /restconf/operations
In XML the YANG module namespace identifies the module:
In JSON the YANG module name identifies the module:
{ 'ietf-system:system-restart' : [null] }
";
}
leaf yang-library-version {
type string {
pattern '\d{4}-\d{2}-\d{2}';
}
config false;
mandatory true;
description
"Identifies the revision date of the ietf-yang-library
module that is implemented by this RESTCONF server.
Indicates the year, month, and day in YYYY-MM-DD
numeric format.";
}
}
}
}
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9. RESTCONF Monitoring
The "ietf-restconf-monitoring" module provides information about the
RESTCONF protocol capabilities and event streams available from the
server. A RESTCONF server MUST implement the
"ietf-restconf-monitoring" module.
YANG tree diagram for "ietf-restconf-monitoring" module:
+--ro restconf-state
+--ro capabilities
| +--ro capability* inet:uri
+--ro streams
+--ro stream* [name]
+--ro name string
+--ro description? string
+--ro replay-support? boolean
+--ro replay-log-creation-time? yang:date-and-time
+--ro access* [encoding]
+--ro encoding string
+--ro location inet:uri
9.1. restconf-state/capabilities
This mandatory container holds the RESTCONF protocol capability URIs
supported by the server.
The server MAY maintain a last-modified timestamp for this container,
and return the "Last-Modified" header field when this data node is
retrieved with the GET or HEAD methods. Note that the last-modified
timestamp for the datastore resource is not affected by changes to
this subtree.
The server SHOULD maintain an entity-tag for this container, and
return the "ETag" header field when this data node is retrieved with
the GET or HEAD methods. Note that the entity-tag for the datastore
resource is not affected by changes to this subtree.
The server MUST include a "capability" URI leaf-list entry for the
"defaults" mode used by the server, defined in Section 9.1.2.
The server MUST include a "capability" URI leaf-list entry
identifying each supported optional protocol feature. This includes
optional query parameters and MAY include other capability URIs
defined outside this document.
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9.1.1. Query Parameter URIs
A new set of RESTCONF Capability URIs are defined to identify the
specific query parameters (defined in Section 4.8) supported by the
server.
The server MUST include a "capability" leaf-list entry for each
optional query parameter that it supports.
+------------+--------+---------------------------------------------+
| Name | Sectio | URI |
| | n | |
+------------+--------+---------------------------------------------+
| depth | 4.8.2 | urn:ietf:params:restconf:capability:depth:1 |
| | | .0 |
| fields | 4.8.3 | urn:ietf:params:restconf:capability:fields: |
| | | 1.0 |
| filter | 4.8.4 | urn:ietf:params:restconf:capability:filter: |
| | | 1.0 |
| replay | 4.8.7 | urn:ietf:params:restconf:capability:replay: |
| | 4.8.8 | 1.0 |
| with- | 4.8.9 | urn:ietf:params:restconf:capability:with- |
| defaults | | defaults:1.0 |
+------------+--------+---------------------------------------------+
RESTCONF Query Parameter URIs
9.1.2. The "defaults" Protocol Capability URI
This URI identifies the "basic-mode" defaults handling mode that is
used by the server for processing default leafs in requests for data
resources. This protocol capability URI MUST be supported by the
server, and MUST be listed in the "capability" leaf-list in
Section 9.3.
+----------+--------------------------------------------------+
| Name | URI |
+----------+--------------------------------------------------+
| defaults | urn:ietf:params:restconf:capability:defaults:1.0 |
+----------+--------------------------------------------------+
RESTCONF defaults capability URI
The URI MUST contain a query parameter named "basic-mode" with one of
the values listed below:
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+------------+------------------------------------------------------+
| Value | Description |
+------------+------------------------------------------------------+
| report-all | No data nodes are considered default |
| trim | Values set to the YANG default-stmt value are |
| | default |
| explicit | Values set by the client are never considered |
| | default |
+------------+------------------------------------------------------+
The "basic-mode" definitions are specified in the "With-Defaults
Capability for NETCONF" [RFC6243].
If the "basic-mode" is set to "report-all" then the server MUST
adhere to the defaults handling behavior defined in Section 2.1 of
[RFC6243].
If the "basic-mode" is set to "trim" then the server MUST adhere to
the defaults handling behavior defined in Section 2.2 of [RFC6243].
If the "basic-mode" is set to "explicit" then the server MUST adhere
to the defaults handling behavior defined in Section 2.3 of
[RFC6243].
Example: (split for display purposes only)
urn:ietf:params:restconf:capability:defaults:1.0?
basic-mode=explicit
9.2. restconf-state/streams
This optional container provides access to the event streams
supported by the server. The server MAY omit this container if no
event streams are supported.
The server will populate this container with a stream list entry for
each stream type it supports. Each stream contains a leaf called
"events" which contains a URI that represents an event stream
resource.
Stream resources are defined in Section 3.8. Notifications are
defined in Section 6.
9.3. RESTCONF Monitoring Module
The "ietf-restconf-monitoring" module defines monitoring information
for the RESTCONF protocol.
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The "ietf-yang-types" and "ietf-inet-types" modules from [RFC6991]
are used by this module for some type definitions.
RFC Ed.: update the date below with the date of RFC publication and
remove this note.
file "ietf-restconf-monitoring@2016-08-15.yang"
module ietf-restconf-monitoring {
namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-monitoring";
prefix "rcmon";
import ietf-yang-types { prefix yang; }
import ietf-inet-types { prefix inet; }
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web:
WG List:
Author: Andy Bierman
Author: Martin Bjorklund
Author: Kent Watsen
";
description
"This module contains monitoring information for the
RESTCONF protocol.
Copyright (c) 2016 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
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// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
// RFC Ed.: remove this note
// Note: extracted from draft-ietf-netconf-restconf-17.txt
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision 2016-08-15 {
description
"Initial revision.";
reference
"RFC XXXX: RESTCONF Protocol.";
}
container restconf-state {
config false;
description
"Contains RESTCONF protocol monitoring information.";
container capabilities {
description
"Contains a list of protocol capability URIs";
leaf-list capability {
type inet:uri;
description "A RESTCONF protocol capability URI.";
}
}
container streams {
description
"Container representing the notification event streams
supported by the server.";
reference
"RFC 5277, Section 3.4, element.";
list stream {
key name;
description
"Each entry describes an event stream supported by
the server.";
leaf name {
type string;
description "The stream name";
reference "RFC 5277, Section 3.4, element.";
}
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leaf description {
type string;
description "Description of stream content";
reference
"RFC 5277, Section 3.4, element.";
}
leaf replay-support {
type boolean;
default false;
description
"Indicates if replay buffer supported for this stream.
If 'true', then the server MUST support the 'start-time'
and 'stop-time' query parameters for this stream.";
reference
"RFC 5277, Section 3.4, element.";
}
leaf replay-log-creation-time {
when "../replay-support" {
description
"Only present if notification replay is supported";
}
type yang:date-and-time;
description
"Indicates the time the replay log for this stream
was created.";
reference
"RFC 5277, Section 3.4,
element.";
}
list access {
key encoding;
min-elements 1;
description
"The server will create an entry in this list for each
encoding format that is supported for this stream.
The media type 'text/event-stream' is expected
for all event streams. This list identifies the
sub-types supported for this stream.";
leaf encoding {
type string;
description
"This is the secondary encoding format within the
'text/event-stream' encoding used by all streams.
The type 'xml' is supported for XML encoding.
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The type 'json' is supported for JSON encoding.";
}
leaf location {
type inet:uri;
mandatory true;
description
"Contains a URL that represents the entry point
for establishing notification delivery via server
sent events.";
}
}
}
}
}
}
10. YANG Module Library
The "ietf-yang-library" module defined in [RFC7895] provides
information about the YANG modules and submodules used by the
RESTCONF server. Implementation is mandatory for RESTCONF servers.
All YANG modules and submodules used by the server MUST be identified
in the YANG module library.
10.1. modules-state/module
This mandatory list contains one entry for each YANG data model
module supported by the server. There MUST be an instance of this
list for every YANG module that is used by the server.
The contents of this list are defined in the "module" YANG list
statement in [RFC7895].
Note that there are no protocol accessible objects in the
"ietf-restconf" module to implement, but it is possible that a server
will list the "ietf-restconf" module in the YANG library if it is
imported (directly or indirectly) by an implemented module.
11. IANA Considerations
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11.1. The "restconf" Relation Type
This specification registers the "restconf" relation type in the Link
Relation Type Registry defined by [RFC5988]:
Relation Name: restconf
Description: Identifies the root of RESTCONF API as configured
on this HTTP server. The "restconf" relation
defines the root of the API defined in RFCXXXX.
Subsequent revisions of RESTCONF will use alternate
relation values to support protocol versioning.
Reference: RFCXXXX
`
11.2. YANG Module Registry
This document registers two URIs as namespaces in the IETF XML
registry [RFC3688]. Following the format in RFC 3688, the following
registration is requested:
URI: urn:ietf:params:xml:ns:yang:ietf-restconf
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-restconf-monitoring
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
This document registers two YANG modules in the YANG Module Names
registry [RFC6020]:
name: ietf-restconf
namespace: urn:ietf:params:xml:ns:yang:ietf-restconf
prefix: rc
// RFC Ed.: replace XXXX with RFC number and remove this note
reference: RFCXXXX
name: ietf-restconf-monitoring
namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-monitoring
prefix: rcmon
// RFC Ed.: replace XXXX with RFC number and remove this note
reference: RFCXXXX
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11.3. Media Types
11.3.1. Media Type application/yang-data+xml
Type name: application
Subtype name: yang-data
Required parameters: None
Optional parameters: None
Encoding considerations: 8-bit
Each conceptual YANG data node is encoded according to the
XML Encoding Rules and Canonical Format for the specific
YANG data node type defined in [RFC7950].
// RFC Ed.: replace 'NN' in Section NN of [RFCXXXX] with the
// section number for Security Considerations
// Replace 'XXXX' in Section NN of [RFCXXXX] with the actual
// RFC number, and remove this note.
Security considerations: Security considerations related
to the generation and consumption of RESTCONF messages
are discussed in Section NN of [RFCXXXX].
Additional security considerations are specific to the
semantics of particular YANG data models. Each YANG module
is expected to specify security considerations for the
YANG data defined in that module.
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Interoperability considerations: [RFCXXXX] specifies the
format of conforming messages and the interpretation
thereof.
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Published specification: RFC XXXX
Applications that use this media type: Instance document
data parsers used within a protocol or automation tool
that utilize YANG defined data structures.
Fragment identifier considerations: Fragment identifiers for
this type are not defined. All YANG data nodes are
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accessible as resources using the path in the request URI.
Additional information:
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): .xml
Macintosh file type code(s): "TEXT"
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Person & email address to contact for further information: See
Authors' Addresses section of [RFCXXXX].
Intended usage: COMMON
Restrictions on usage: N/A
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Author: See Authors' Addresses section of [RFCXXXX].
Change controller: Internet Engineering Task Force
(mailto:iesg&ietf.org).
Provisional registration? (standards tree only): no
11.3.2. Media Type application/yang-data+json
Type name: application
Subtype name: yang-data+json
Required parameters: None
Optional parameters: None
Encoding considerations: 8-bit
Each conceptual YANG data node is encoded according to
[RFC7951]. A data annotation is encoded according to
[RFC7952].
// RFC Ed.: replace 'NN' in Section NN of [RFCXXXX] with the
// section number for Security Considerations
// Replace 'XXXX' in Section NN of [RFCXXXX] with the actual
// RFC number, and remove this note.
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Security considerations: Security considerations related
to the generation and consumption of RESTCONF messages
are discussed in Section NN of [RFCXXXX].
Additional security considerations are specific to the
semantics of particular YANG data models. Each YANG module
is expected to specify security considerations for the
YANG data defined in that module.
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Interoperability considerations: [RFCXXXX] specifies the format
of conforming messages and the interpretation thereof.
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Published specification: RFC XXXX
Applications that use this media type: Instance document
data parsers used within a protocol or automation tool
that utilize YANG defined data structures.
Fragment identifier considerations: The syntax and semantics
of fragment identifiers are the same as specified for the
"application/json" media type.
Additional information:
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): .json
Macintosh file type code(s): "TEXT"
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Person & email address to contact for further information: See
Authors' Addresses section of [RFCXXXX].
Intended usage: COMMON
Restrictions on usage: N/A
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
Author: See Authors' Addresses section of [RFCXXXX].
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Change controller: Internet Engineering Task Force
(mailto:iesg&ietf.org).
Provisional registration? (standards tree only): no
11.4. RESTCONF Capability URNs
[Note to RFC Editor:
The RESTCONF Protocol Capability Registry does not yet exist;
Need to ask IANA to create it; remove this note for publication
]
This document defines a registry for RESTCONF capability identifiers.
The name of the registry is "RESTCONF Capability URNs". The review
policy for this registry is "IETF Review". The registry shall record
for each entry:
o the name of the RESTCONF capability. By convention, this name
begins with the colon ':' character.
o the URN for the RESTCONF capability.
This document registers several capability identifiers in "RESTCONF
Capability URNs" registry:
Index
Capability Identifier
------------------------
:defaults
urn:ietf:params:restconf:capability:defaults:1.0
:depth
urn:ietf:params:restconf:capability:depth:1.0
:fields
urn:ietf:params:restconf:capability:fields:1.0
:filter
urn:ietf:params:restconf:capability:filter:1.0
:replay
urn:ietf:params:restconf:capability:replay:1.0
:with-defaults
urn:ietf:params:restconf:capability:with-defaults:1.0
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12. Security Considerations
The "ietf-restconf-monitoring" YANG module defined in this memo is
designed to be accessed via the NETCONF protocol [RFC6241]. The
lowest NETCONF layer is the secure transport layer, and the
mandatory-to-implement secure transport is Secure Shell (SSH)
[RFC6242]. The NETCONF access control model [RFC6536] provides the
means to restrict access for particular NETCONF users to a pre-
configured subset of all available NETCONF protocol operations and
content.
The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement
secure transport is TLS [RFC5246]. The RESTCONF protocol uses the
NETCONF access control model [RFC6536], which provides the means to
restrict access for particular RESTCONF users to a preconfigured
subset of all available RESTCONF protocol operations and content.
This section provides security considerations for the resources
defined by the RESTCONF protocol. Security considerations for HTTPS
are defined in [RFC7230]. RESTCONF does not specify which YANG
modules a server needs to support, except the
"ietf-restconf-monitoring" module. Security considerations for the
other modules manipulated by RESTCONF can be found in the documents
defining those YANG modules.
This document does not require use of a specific client
authentication mechanism or authorization model, but it does require
that a client authentication mechanism and authorization model is
used whenever a client accesses a protected resource. Client
authentication MUST be implemented using client certificates or MUST
be implemented using an HTTP authentication scheme. Client
authorization MAY be configured using the NETCONF Access Control
Model (NACM) [RFC6536].
Configuration information is by its very nature sensitive. Its
transmission in the clear and without integrity checking leaves
devices open to classic eavesdropping and false data injection
attacks. Configuration information often contains passwords, user
names, service descriptions, and topological information, all of
which are sensitive. There are many patterns of attack that have
been observed through operational practice with existing management
interfaces. It would be wise for implementers to research them, and
take them into account when implementing this protocol.
Different environments may well allow different rights prior to and
then after authentication. When a RESTCONF operation is not properly
authorized, the RESTCONF server MUST return a "401 Unauthorized"
status-line. Note that authorization information can be exchanged in
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the form of configuration information, which is all the more reason
to ensure the security of the connection. Note that it is possible
for a client to detect configuration changes in data resources it is
not authorized to access by monitoring changes in the ETag and Last-
Modified header fields returned by the server for the datastore
resource.
A RESTCONF server implementation SHOULD attempt to prevent system
disruption due to excessive resource consumption required to fulfill
edit requests via the POST, PUT, and PATCH methods. It may be
possible to construct an attack on such a RESTCONF server, which
attempts to consume all available memory or other resource types.
13. Acknowledgements
The authors would like to thank the following people for their
contributions to this document: Ladislav Lhotka, Juergen
Schoenwaelder, Rex Fernando, Robert Wilton, and Jonathan Hansford.
The authors would like to thank the following people for their
excellent technical reviews of this document: Mehmet Ersue, Mahesh
Jethanandani, Qin Wu, Joe Clarke, Bert Wijnen, Ladislav Lhotka,
Rodney Cummings, Frank Xialiang, Tom Petch, Robert Sparks, Balint
Uveges, Randy Presuhn, Sue Hares, Mark Nottingham, Benoit Claise,
Dale Worley, and Lionel Morand.
Contributions to this material by Andy Bierman are based upon work
supported by the United States Army, Space & Terrestrial
Communications Directorate (S&TCD) under Contract No. W15P7T-
13-C-A616. Any opinions, findings and conclusions or recommendations
expressed in this material are those of the author(s) and do not
necessarily reflect the views of The Space & Terrestrial
Communications Directorate (S&TCD).
14. References
14.1. Normative References
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
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[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, July 2008.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and T. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[RFC5789] Dusseault, L. and J. Snell, "PATCH Method for HTTP",
RFC 5789, March 2010.
[RFC5988] Nottingham, M., "Web Linking", RFC 5988, October 2010.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, March 2011.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, June 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
.
[RFC6243] Bierman, A. and B. Lengyel, "With-defaults Capability for
NETCONF", RFC 6243, June 2011.
[RFC6415] Hammer-Lahav, E. and B. Cook, "Web Host Metadata",
RFC 6415, October 2011.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536, March
2012.
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[RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M.,
and D. Orchard, "URI Template", RFC 6570, March 2012.
[RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
July 2013.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, .
[RFC7230] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Message Syntax and Routing", RFC 7230, June
2014.
[RFC7231] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Semantics and Content", RFC 7231, June 2014.
[RFC7232] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Conditional Requests", RFC 7232, June 2014.
[RFC7235] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Authentication", RFC 7235, June 2014.
[RFC7320] Nottingham, M., "URI Design and Ownership", BCP 190,
RFC 7320, July 2014.
[RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
NETCONF Protocol over Transport Layer Security (TLS) with
Mutual X.509 Authentication", RFC 7589,
DOI 10.17487/RFC7589, June 2015,
.
[RFC7895] Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
Library", RFC 7895, June 2016.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
.
[RFC7952] Lhotka, L., "Defining and Using Metadata with YANG",
RFC 7952, DOI 10.17487/RFC7952, August 2016,
.
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[W3C.REC-eventsource-20150203]
Hickson, I., "Server-Sent Events", World Wide Web
Consortium Recommendation REC-eventsource-20150203,
February 2015,
.
[W3C.REC-xml-20081126]
Yergeau, F., Maler, E., Paoli, J., Sperberg-McQueen, C.,
and T. Bray, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", World Wide Web Consortium Recommendation REC-
xml-20081126, November 2008,
.
[XPath] Clark, J. and S. DeRose, "XML Path Language (XPath)
Version 1.0", World Wide Web Consortium Recommendation
REC-xpath-19991116, November 1999,
.
14.2. Informative References
[I-D.ietf-netconf-yang-patch]
Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch
Media Type", draft-ietf-netconf-yang-patch-08 (work in
progress), March 2016.
[rest-dissertation]
Fielding, R., "Architectural Styles and the Design of
Network-based Software Architectures", 2000.
Appendix A. Change Log
-- RFC Ed.: remove this section before publication.
The RESTCONF issue tracker can be found here: https://github.com/
netconf-wg/restconf/issues
A.1. v16 to v17
o various clarifications from NETCONF WG mailing list
o updated YANG 1.1 and YANG/JSON references to RFC numbers
o fixed notification namespace and eventTime name bug
o changed media type application/yang-data-xml to application/yang-
data+xml
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o update fragment identifier considerations section for application/
yang-data+xml
o clarify HTTP version requirements
A.2. v15 to v16
o changed media type application/yang-data to application/yang-data-
xml
o changed header to header field
o added linewrap convention in terminology and applied in many
examples
o clarified DELETE for leaf-list and list
o clarified URI format for lists without keys or duplicate leaf-
lists
o added 'yang-data extension' term and clarified 'YANG data
template' term
o clarified that the fragment component is not part of the request
URI, per HTTP
o clarified request URI "api-path" syntax
o clarified many examples
A.3. v14 to v15
o added text for HTTP/2 usage
o changed media type definitions per review comments
o added some clarifications and typos
o added error-tag mapping for 406 and 412 errors
o added clarifications based on ops-dir review by Lionel Morand
o clarified PUT and POST differences for creating a data resource
o clarify PUT for a datastore resource
o added clarifications from Gen-Art review by Robert Sparks
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o clarified terminology in many places
A.4. v13 - v14
This release addresses github issues #61, #62, #63, #65, #66, and
#67.
o change term 'server' to 'NETCONF server'
o add term 'RESTCONF server' also called 'server'
o change term 'client' to 'NETCONF client'
o add term 'RESTCONF client' also called 'client'
o remove unused YANG terms
o clarified operation resource and schema resource terms
o clarified abstract and intro: RESTCONF uses NETCONF datastore
concepts
o removed term 'protocol operation'; use 'RPC operation' instead
o clarified edit operation from NETCONF as nc:operation
o clarified retrieval of an operation resource
o remove ETag and Last-Modified requirements for /modules-state and
/modules-state/module objects, since these are not configuration
data nodes
o clarified Last-Modified and ETag requirements for datastore and
data resources
o clarified defaults retrieval for leaf and leaf-list target
resources
o clarified request message-body for operation resources
o clarified query parameters for GET also allowed for HEAD
o clarified error handling for query parameters
o clarified XPath function library for "filter" parameter
o added example for 'edit a data resource'
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o added term 'notification replay' from RFC 5277
o clarified unsupported encoding format error handling
o change term 'meta-data' to 'metadata'
o clarified RESTCONF metadata definition
o clarified error info not returned for 1xx, 2xx, and 3xx ranges
o clarified operations description in ietf-restconf module
o clarified Acknowledgements section
o clarified some examples
o update some references
o update RFC 2119 boilerplate
o remove requirements that simply restate HTTP requirements
o remove Pragma: no-cache from examples since RFC 7234 says this
pragma is not defined for responses
o remove suggestion MAY send Pragma: no-cache in response
o remove table of HTTP status codes used in RESTCONF
o changed media type names so they conform to RFC 6838
o clarified too-big error-tag conversion
o update SSE reference
o clarify leaf-list identifier encoding
o removed all media types except yang-data
o changed restconf-media-type extension to be more generic yang-data
extension
A.5. v12 - v13
o fix YANG library module examples (now called module-state)
o fix terminology idnit issue
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o removed RFC 2818 reference (changed citation to RFC 7230)
A.6. v11 - v12
o clarify query parameter requirements
o move filter query section to match table order in sec. 4.8
o clarify that depth default is entire subtree for datastore
resource
o change ietf-restconf to YANG 1.1 to use anydata instead of anyxml
o made implementation of timestamps optional since ETags are
mandatory
o removed confusing text about data resource definition revision
date
o clarify that errors should be returned for any resource type
o clarified media subtype (not type) for error response
o clarified client SHOULD (not MAY) specify errors format in Accept
header
o clarified terminology in many sections
A.7. v10 - v11
o change term 'operational data' to 'state data'
o clarify :startup behavior
o clarify X.509 security text
o change '403 Forbidden' to '401 Unauthorized' for GET error
o clarify MUST have one "restconf" link relation
o clarify that NV-storage is not mandatory
o clarify how "Last-Modified" and "ETag" header info can be used by
a client
o clarify meaning of mandatory parameter
o fix module name in action examples
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o clarify operation resource request needs to be known to parse the
output
o clarify ordered-by user terminology
o fixed JSON example in D.1.1
A.8. v09 - v10
o address review comments: github issue #36
o removed intro text about no knowledge of NETCONF needed
o clarified candidate and confirmed-commit behavior in sec. 1.3
o clarified that a RESTCONF server MUST support TLS
o clarified choice of 403 or 404 error
o fixed forward references to URI template (w/reference at first
use)
o added reference to HTML5
o made error terminology more consistent
o clarified that only 1 list or leaf-list instance can be returned
in an XML response message-body
o clarified that more than 1 instance must not be created by a POST
method
o clarified that PUT cannot be used to change a leaf-list value or
any list key values
o clarified that PATCH cannot be used to change a leaf-list value or
any list key values
o clarified that DELETE should not be used to delete more than one
instance of a leaf-list or list
o update JSON RFC reference
o specified that leaf-list instances are data resources
o specified how a leaf-list instance identifier is constructed
o fixed get-schema example
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o clarified that if no Accept header the server SHOULD return the
type specified in RESTCONF, but MAY return any media-type,
according to HTTP rules
o clarified that server SHOULD maintain timestamp and etag for data
resources
o clarified default for content query parameter
o moved terminology section earlier in doc to avoid forward usage
o clarified intro text wrt/ interactions with NETCONF and access to
specific datastores
o clarified server implementation requirements for YANG defaults
o clarified that Errors is not a resource, just a media type
o clarified that HTTP without TLS MUST NOT be used
o add RESTCONF Extensibility section to make it clear how RESTCONF
will be extended in the future
o add text warning that NACM does not work with HTTP caching
o remove sec. 5.2 Message Headers
o remove 202 Accepted from list of used status-lines -- not allowed
o made implementation of OPTIONS MUST instead of SHOULD
o clarified that successful PUT for altering data returns 204
o fixed "point" parameter example
o added example of alternate value for root resource discovery
o added YANG action examples
o fixed some JSON examples
o changed default value for content query parameter to "all"
o changed empty container JSON encoding from "[null]" to "{}"
o added mandatory /restconf/yang-library-version leaf to advertise
revision-date of the YANG library implemented by the server
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o clarified URI encoding rules for leaf-list
o clarified sec. 2.2 wrt/ certificates and TLS
o added update procedure for entity tag and timestamp
A.9. v08 - v09
o fix introduction text regarding implementation requirements for
the ietf-yang-library
o clarified HTTP authentication requirements
o fix host-meta example
o changed list key encoding to clarify that quoted strings are not
allowed. Percent-encoded values are used if quotes would be
required. A missing key is treated as a zero-length string
o Fixed example of percent-encoded string to match YANG model
o Changed streams examples to align with naming already used
A.10. v07 - v08
o add support for YANG 1.1 action statement
o changed mandatory encoding from XML to XML or JSON
o fix syntax in fields parameter definition
o add meta-data encoding examples for XML and JSON
o remove RFC 2396 references and update with 3986
o change encoding of a key so quoted string are not used, since they
are already percent-encoded. A zero-length string is not encoded
(/list=foo,,baz)
o Add example of percent-encoded key value
A.11. v06 - v07
o fixed all issues identified in email from Jernej Tuljak in netconf
email 2015-06-22
o fixed error example bug where error-urlpath was still used.
Changed to error-path.
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o added mention of YANG Patch and informative reference
o added support for YANG 1.1, specifically support for anydata and
actions
o removed the special field value "*", since it is no longer needed
A.12. v05 - v06
o fixed RESTCONF issue #23 (ietf-restconf-monitoring bug)
A.13. v04 - v05
o changed term 'notification event' to 'event notification'
o removed intro text about framework and meta-model
o removed early mention of API resources
o removed term unified datastore and cleaned up text about NETCONF
datastores
o removed text about not immediate persistence of edits
o removed RESTCONF-specific data-resource-identifier typedef and its
usage
o clarified encoding of key leafs
o changed several examples from JSON to XML encoding
o made 'insert' and 'point' query parameters mandatory to implement
o removed ":insert" capability URI
o renamed stream/encoding to stream/access
o renamed stream/encoding/type to stream/access/encoding
o renamed stream/encoding/events to stream/access/location
o changed XPath from informative to normative reference
o changed rest-dissertation from normative to informative reference
o changed example-jukebox playlist 'id' from a data-resource-
identifier to a leafref pointing at the song name
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A.14. v03 - v04
o renamed 'select' to 'fields' (#1)
o moved collection resource and page capability to draft-ietf-
netconf-restconf-collection-00 (#3)
o added mandatory "defaults" protocol capability URI (#4)
o added optional "with-defaults" query parameter URI (#4)
o clarified authentication procedure (#9)
o moved ietf-yang-library module to draft-ietf-netconf-yang-
library-00 (#13)
o clarified that JSON encoding of module name in a URI MUST follow
the netmod-yang-json encoding rules (#14)
o added restconf-media-type extension (#15)
o remove "content" query parameter URI and made this parameter
mandatory (#16)
o clarified datastore usage
o changed lock-denied error example
o added with-defaults query parameter example
o added term "RESTCONF Capability"
o changed NETCONF Capability URI registry usage to new RESTCONF
Capability URI Registry usage
A.15. v02 - v03
o added collection resource
o added "page" query parameter capability
o added "limit" and "offset" query parameters, which are available
if the "page" capability is supported
o added "stream list" term
o fixed bugs in some examples
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o added "encoding" list within the "stream" list to allow different
URLs for XML and JSON encoding.
o made XML MUST implement and JSON MAY implement for servers
o re-add JSON notification examples (previously removed)
o updated JSON references
A.16. v01 - v02
o moved query parameter definitions from the YANG module back to the
plain text sections
o made all query parameters optional to implement
o defined query parameter capability URI
o moved 'streams' to new YANG module (ietf-restconf-monitoring)
o added 'capabilities' container to new YANG module (ietf-restconf-
monitoring)
o moved 'modules' container to new YANG module (ietf-yang-library)
o added new leaf 'module-set-id' (ietf-yang-library)
o added new leaf 'conformance' (ietf-yang-library)
o changed 'schema' leaf to type inet:uri that returns the location
of the YANG schema (instead of returning the schema directly)
o changed 'events' leaf to type inet:uri that returns the location
of the event stream resource (instead of returning events
directly)
o changed examples for yang.api resource since the monitoring
information is no longer in this resource
o closed issue #1 'select parameter' since no objections to the
proposed syntax
o closed "encoding of list keys" issue since no objection to new
encoding of list keys in a target resource URI.
o moved open issues list to the issue tracker on github
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A.17. v00 - v01
o fixed content=nonconfig example (non-config was incorrect)
o closed open issue 'message-id'. There is no need for a message-id
field, and RFC 2392 does not apply.
o closed open issue 'server support verification'. The headers used
by RESTCONF are widely supported.
o removed encoding rules from section on RESTCONF Meta-Data. This
is now defined in "I-D.lhotka-netmod-yang-json".
o added media type application/yang.errors to map to errors YANG
grouping. Updated error examples to use new media type.
o closed open issue 'additional datastores'. Support may be added
in the future to identify new datastores.
o closed open issue 'PATCH media type discovery'. The section on
PATCH has an added sentence on the Accept-Patch header.
o closed open issue 'YANG to resource mapping'. Current mapping of
all data nodes to resources will be used in order to allow
mandatory DELETE support. The PATCH operation is optional, as
well as the YANG Patch media type.
o closed open issue '_self links for HATEOAS support'. It was
decided that they are redundant because they can be derived from
the YANG module for the specific data.
o added explanatory text for the 'select' parameter.
o added RESTCONF Path Resolution section for discovering the root of
the RESTCONF API using the /.well-known/host-meta.
o added an "error" media type to for structured error messages
o added Secure Transport section requiring TLS
o added Security Considerations section
o removed all references to "REST-like"
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A.18. bierman:restconf-04 to ietf:restconf-00
o updated open issues section
Appendix B. Open Issues
-- RFC Ed.: remove this section before publication.
The RESTCONF issues are tracked on github.com:
https://github.com/netconf-wg/restconf/issues
Appendix C. Example YANG Module
The example YANG module used in this document represents a simple
media jukebox interface.
YANG Tree Diagram for "example-jukebox" Module
+--rw jukebox!
+--rw library
| +--rw artist* [name]
| | +--rw name string
| | +--rw album* [name]
| | +--rw name string
| | +--rw genre? identityref
| | +--rw year? uint16
| | +--rw admin
| | | +--rw label? string
| | | +--rw catalogue-number? string
| | +--rw song* [name]
| | +--rw name string
| | +--rw location string
| | +--rw format? string
| | +--rw length? uint32
| +--ro artist-count? uint32
| +--ro album-count? uint32
| +--ro song-count? uint32
+--rw playlist* [name]
| +--rw name string
| +--rw description? string
| +--rw song* [index]
| +--rw index uint32
| +--rw id instance-identifier
+--rw player
+--rw gap? decimal64
rpcs:
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+---x play
+--ro input
+--ro playlist string
+--ro song-number uint32
C.1. example-jukebox YANG Module
module example-jukebox {
namespace "http://example.com/ns/example-jukebox";
prefix "jbox";
organization "Example, Inc.";
contact "support at example.com";
description "Example Jukebox Data Model Module";
revision "2016-08-15" {
description "Initial version.";
reference "example.com document 1-4673";
}
identity genre {
description "Base for all genre types";
}
// abbreviated list of genre classifications
identity alternative {
base genre;
description "Alternative music";
}
identity blues {
base genre;
description "Blues music";
}
identity country {
base genre;
description "Country music";
}
identity jazz {
base genre;
description "Jazz music";
}
identity pop {
base genre;
description "Pop music";
}
identity rock {
base genre;
description "Rock music";
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}
container jukebox {
presence
"An empty container indicates that the jukebox
service is available";
description
"Represents a jukebox resource, with a library, playlists,
and a play operation.";
container library {
description "Represents the jukebox library resource.";
list artist {
key name;
description
"Represents one artist resource within the
jukebox library resource.";
leaf name {
type string {
length "1 .. max";
}
description "The name of the artist.";
}
list album {
key name;
description
"Represents one album resource within one
artist resource, within the jukebox library.";
leaf name {
type string {
length "1 .. max";
}
description "The name of the album.";
}
leaf genre {
type identityref { base genre; }
description
"The genre identifying the type of music on
the album.";
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}
leaf year {
type uint16 {
range "1900 .. max";
}
description "The year the album was released";
}
container admin {
description
"Administrative information for the album.";
leaf label {
type string;
description "The label that released the album.";
}
leaf catalogue-number {
type string;
description "The album's catalogue number.";
}
}
list song {
key name;
description
"Represents one song resource within one
album resource, within the jukebox library.";
leaf name {
type string {
length "1 .. max";
}
description "The name of the song";
}
leaf location {
type string;
mandatory true;
description
"The file location string of the
media file for the song";
}
leaf format {
type string;
description
"An identifier string for the media type
for the file associated with the
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'location' leaf for this entry.";
}
leaf length {
type uint32;
units "seconds";
description
"The duration of this song in seconds.";
}
} // end list 'song'
} // end list 'album'
} // end list 'artist'
leaf artist-count {
type uint32;
units "songs";
config false;
description "Number of artists in the library";
}
leaf album-count {
type uint32;
units "albums";
config false;
description "Number of albums in the library";
}
leaf song-count {
type uint32;
units "songs";
config false;
description "Number of songs in the library";
}
} // end library
list playlist {
key name;
description
"Example configuration data resource";
leaf name {
type string;
description
"The name of the playlist.";
}
leaf description {
type string;
description
"A comment describing the playlist.";
}
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list song {
key index;
ordered-by user;
description
"Example nested configuration data resource";
leaf index { // not really needed
type uint32;
description
"An arbitrary integer index for this playlist song.";
}
leaf id {
type instance-identifier;
mandatory true;
description
"Song identifier. Must identify an instance of
/jukebox/library/artist/album/song/name.";
}
}
}
container player {
description
"Represents the jukebox player resource.";
leaf gap {
type decimal64 {
fraction-digits 1;
range "0.0 .. 2.0";
}
units "tenths of seconds";
description "Time gap between each song";
}
}
}
rpc play {
description "Control function for the jukebox player";
input {
leaf playlist {
type string;
mandatory true;
description "playlist name";
}
leaf song-number {
type uint32;
mandatory true;
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description "Song number in playlist to play";
}
}
}
}
Appendix D. RESTCONF Message Examples
The examples within this document use the normative YANG module
"ietf-restconf" defined in Section 8 and the non-normative example
YANG module "example-jukebox" defined in Appendix C.1.
This section shows some typical RESTCONF message exchanges.
D.1. Resource Retrieval Examples
D.1.1. Retrieve the Top-level API Resource
The client starts by retrieving the RESTCONF root resource:
GET /.well-known/host-meta HTTP/1.1
Host: example.com
Accept: application/xrd+xml
The server might respond:
HTTP/1.1 200 OK
Content-Type: application/xrd+xml
Content-Length: nnn
The client may then retrieve the top-level API resource, using the
root resource "/restconf".
GET /restconf HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows:
[RFC Editor Note: Adjust the date (2016-04-09) for ietf-yang-library
below to the date in the published ietf-yang-library YANG module, and
remove this note.]
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"ietf-restconf:restconf" : {
"data" : {},
"operations" : {},
"yang-library-version" : "2016-06-21"
}
}
To request that the response content to be encoded in XML, the
"Accept" header can be used, as in this example request:
GET /restconf HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server will return the same conceptual data either way, which
might be as follows :
[RFC Editor Note: Adjust the date for ietf-yang-library below to the
date in the published ietf-yang-library YANG module, and remove this
note.]
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+xml
2016-06-21
D.1.2. Retrieve The Server Module Information
It is possible the YANG library module will change over time. The
client can retrieve the revision date of the ietf-yang-library
supported by the server from the API resource, as described in the
previous section.
In this example the client is retrieving the modules information from
the server in JSON format:
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GET /restconf/data/ietf-yang-library:modules-state HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows:
[RFC Editor Note: Adjust the date for ietf-yang-library below to the
date in the published ietf-yang-library YANG module, and remove this
note.]
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Cache-Control: no-cache
Last-Modified: Sun, 22 Apr 2016 01:00:14 GMT
Content-Type: application/yang-data+json
{
"ietf-yang-library:modules-state" : {
"module-set-id" : "5479120c17a619545ea6aff7aa19838b036ebbd7",
"module" : [
{
"name" : "foo",
"revision" : "2012-01-02",
"schema" : "https://example.com/modules/foo/2012-01-02",
"namespace" : "http://example.com/ns/foo",
"feature" : [ "feature1", "feature2" ],
"deviation" : [
{
"name" : "foo-dev",
"revision" "2012-02-16"
}
],
"conformance-type" : "implement"
},
{
"name" : "ietf-yang-library",
"revision" : "2016-06-21",
"schema" : "https://example.com/modules/\
ietf-yang-library/2016-06-21",
"namespace" :
"urn:ietf:params:xml:ns:yang:ietf-yang-library",
"conformance-type" : "implement"
},
{
"name" : "foo-types",
"revision" : "2012-01-05",
"schema" :
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"https://example.com/modules/foo-types/2012-01-05",
"namespace" : "http://example.com/ns/foo-types",
"conformance-type" : "import"
},
{
"name" : "bar",
"revision" : "2012-11-05",
"schema" : "https://example.com/modules/bar/2012-11-05",
"namespace" : "http://example.com/ns/bar",
"feature" : [ "bar-ext" ],
"conformance-type" : "implement",
"submodule" : [
{
"name" : "bar-submod1",
"revision" : "2012-11-05",
"schema" :
"https://example.com/modules/bar-submod1/2012-11-05"
},
{
"name" : "bar-submod2",
"revision" : "2012-11-05",
"schema" :
"https://example.com/modules/bar-submod2/2012-11-05"
}
]
}
]
}
}
D.1.3. Retrieve The Server Capability Information
In this example the client is retrieving the capability information
from the server in XML format, and the server supports all the
RESTCONF query parameters, plus one vendor parameter:
GET /restconf/data/ietf-restconf-monitoring:restconf-state/\
capabilities HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
The server might respond as follows:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:02:00 GMT
Server: example-server
Cache-Control: no-cache
Last-Modified: Sun, 22 Apr 2016 01:00:14 GMT
Content-Type: application/yang-data+xml
\
urn:ietf:params:restconf:capability:defaults:1.0?\
basic-mode=explicit\
\
urn:ietf:params:restconf:capability:with-defaults:1.0\
\
urn:ietf:params:restconf:capability:depth:1.0\
\
urn:ietf:params:restconf:capability:fields:1.0\
\
urn:ietf:params:restconf:capability:filter:1.0\
\
urn:ietf:params:restconf:capability:start-time:1.0\
\
urn:ietf:params:restconf:capability:stop-time:1.0\
\
http://example.com/capabilities/myparam\
D.2. Edit Resource Examples
D.2.1. Create New Data Resources
To create a new "artist" resource within the "library" resource, the
client might send the following request.
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POST /restconf/data/example-jukebox:jukebox/library HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{
"example-jukebox:artist" : [
{
"name" : "Foo Fighters"
}
]
}
If the resource is created, the server might respond as follows:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2016 17:02:00 GMT
Server: example-server
Location: https://example.com/restconf/data/\
example-jukebox:jukebox/library/artist=Foo%20Fighters
Last-Modified: Mon, 23 Apr 2016 17:02:00 GMT
ETag: "b3830f23a4c"
To create a new "album" resource for this artist within the "jukebox"
resource, the client might send the following request:
POST /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
Wasting Light2011
If the resource is created, the server might respond as follows:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2016 17:03:00 GMT
Server: example-server
Location: https://example.com/restconf/data/\
example-jukebox:jukebox/library/artist=Foo%20Fighters/\
album=Wasting%20Light
Last-Modified: Mon, 23 Apr 2016 17:03:00 GMT
ETag: "b8389233a4c"
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D.2.2. Detect Resource Entity-Tag Change
In this example, the server just supports the datastore last-changed
timestamp. After the previous request, the client has cached the
"Last-Modified" header and the Location header from the response to
provide in the following request to patch an "album" list entry with
key value "Wasting Light". Only the "genre" field is being updated.
PATCH /restconf/data/example-jukebox:jukebox/\
library/artist=Foo%20Fighters/album=Wasting%20Light/\
genre HTTP/1.1
Host: example.com
If-Unmodified-Since: Mon, 23 Apr 2016 17:03:00 GMT
Content-Type: application/yang-data+json
{ "example-jukebox:genre" : "example-jukebox:alternative" }
In this example the datastore resource has changed since the time
specified in the "If-Unmodified-Since" header. The server might
respond:
HTTP/1.1 412 Precondition Failed
Date: Mon, 23 Apr 2016 19:01:00 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2016 17:45:00 GMT
ETag: "b34aed893a4c"
D.2.3. Edit a Datastore Resource
In this example, assume there is a top-level data resource named
"system" from the example-system module, and this container has a
child leaf called "enable-jukebox-streaming":
container system {
leaf enable-jukebox-streaming {
type boolean;
}
}
In this example PATCH is used by the client to modify 2 top-level
resources at once, in order to enable jukebox streaming and add an
"album" sub-resource to each of 2 "artist" resources:
PATCH /restconf/data HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
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trueFoo FightersOne by One2012Nick Cave and the Bad SeedsTender Prey1988
D.2.4. Edit a Data Resource
In this example, the client modifies one data node by adding an
"album" sub-resource by sending a PATCH for the data resource:
PATCH /restconf/data/example-jukebox:jukebox/library/\
artist=Nick%20Cave%20and%20the%20Bad%20Seeds HTTP/1.1
Host: example.com
Content-Type: application/yang-data+xml
Nick Cave and the Bad SeedsThe Good Son1990
D.3. Query Parameter Examples
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D.3.1. "content" Parameter
The "content" parameter is used to select the type of data child
resources (configuration and/or not configuration) that are returned
by the server for a GET method request.
In this example, a simple YANG list that has configuration and non-
configuration child resources.
container events
list event {
key name;
leaf name { type string; }
leaf description { type string; }
leaf event-count {
type uint32;
config false;
}
}
}
Example 1: content=all
To retrieve all the child resources, the "content" parameter is set
to "all", or omitted, since this is the default value. The client
might send:
GET /restconf/data/example-events:events?\
content=all HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+json
{
"example-events:events" : {
"event" : [
{
"name" : "interface-up",
"description" : "Interface up notification count",
"event-count" : 42
},
{
"name" : "interface-down",
"description" : "Interface down notification count",
"event-count" : 4
}
]
}
}
Example 2: content=config
To retrieve only the configuration child resources, the "content"
parameter is set to "config". Note that the "ETag" and
"Last-Modified" headers are only returned if the content parameter
value is "config".
GET /restconf/data/example-events:events?\
content=config HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:11:30 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2016 13:01:20 GMT
ETag: "eeeada438af"
Cache-Control: no-cache
Content-Type: application/yang-data+json
{
"example-events:events" : {
"event" : [
{
"name" : "interface-up",
"description" : "Interface up notification count"
},
{
"name" : "interface-down",
"description" : "Interface down notification count"
}
]
}
}
Example 3: content=nonconfig
To retrieve only the non-configuration child resources, the "content"
parameter is set to "nonconfig". Note that configuration ancestors
(if any) and list key leafs (if any) are also returned. The client
might send:
GET /restconf/data/example-events:events?\
content=nonconfig HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+json
{
"example-events:events" : {
"event" : [
{
"name" : "interface-up",
"event-count" : 42
},
{
"name" : "interface-down",
"event-count" : 4
}
]
}
}
D.3.2. "depth" Parameter
The "depth" parameter is used to limit the number of levels of child
resources that are returned by the server for a GET method request.
The depth parameter starts counting levels at the level of the target
resource that is specified, so that a depth level of "1" includes
just the target resource level itself. A depth level of "2" includes
the target resource level and its child nodes.
This example shows how different values of the "depth" parameter
would affect the reply content for retrieval of the top-level
"jukebox" data resource.
Example 1: depth=unbounded
To retrieve all the child resources, the "depth" parameter is not
present or set to the default value "unbounded".
GET /restconf/data/example-jukebox:jukebox?\
depth=unbounded HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
HTTP/1.1 200 OK
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Date: Mon, 23 Apr 2016 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+json
{
"example-jukebox:jukebox" : {
"library" : {
"artist" : [
{
"name" : "Foo Fighters",
"album" : [
{
"name" : "Wasting Light",
"genre" : "example-jukebox:alternative",
"year" : 2011,
"song" : [
{
"name" : "Wasting Light",
"location" :
"/media/foo/a7/wasting-light.mp3",
"format" : "MP3",
"length" " 286
},
{
"name" : "Rope",
"location" : "/media/foo/a7/rope.mp3",
"format" : "MP3",
"length" " 259
}
]
}
]
}
]
},
"playlist" : [
{
"name" : "Foo-One",
"description" : "example playlist 1",
"song" : [
{
"index" : 1,
"id" : "/example-jukebox:jukebox/library\
/artist[name='Foo Figthers']\
/album[name='Wasting Light']\
/song[name=Rope']"
},
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{
"index" : 2,
"id" : "/example-jukebox:jukebox/library\
/artist[name='Foo Figthers']\
/album[name='Wasting Light']\
/song[name=Bridge Burning']"
}
]
}
],
"player" : {
"gap" : 0.5
}
}
}
Example 2: depth=1
To determine if 1 or more resource instances exist for a given target
resource, the value one is used.
GET /restconf/data/example-jukebox:jukebox?depth=1 HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+json
{
"example-jukebox:jukebox" : {}
}
Example 3: depth=3
To limit the depth level to the target resource plus 2 child resource
layers the value "3" is used.
GET /restconf/data/example-jukebox:jukebox?depth=3 HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond:
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:11:30 GMT
Server: example-server
Cache-Control: no-cache
Content-Type: application/yang-data+json
{
"example-jukebox:jukebox" : {
"library" : {
"artist" : {}
},
"playlist" : [
{
"name" : "Foo-One",
"description" : "example playlist 1",
"song" : {}
}
],
"player" : {
"gap" : 0.5
}
}
}
D.3.3. "fields" Parameter
In this example the client is retrieving the datastore resource in
JSON format, but retrieving only the "modules-state/module" list, and
only the "name" and "revision" nodes from each list entry. Note that
top node returned by the server matches the target resource node
(which is "data" in this example). The "module-set-id" leaf is not
returned because it is not selected in the fields expression.
GET /restconf/data?fields=ietf-yang-library:modules-state/\
module(name;revision) HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows.
[RFC Editor Note: Adjust the date for ietf-yang-library below to the
date in the published ietf-yang-library YANG module, and remove this
note.]
[RFC Editor Note: Adjust the date for ietf-restconf-monitoring below
to the date in the published ietf-restconf-monitoring YANG module,
and remove this note.]
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"ietf-restconf:data" : {
"ietf-yang-library:modules-state" : {
"module" : [
{
"name" : "example-jukebox",
"revision" : "2015-06-04"
},
{
"name" : "ietf-inet-types",
"revision" : "2013-07-15"
},
{
"name" : "ietf-restconf-monitoring",
"revision" : "2016-03-16"
},
{
"name" : "ietf-yang-library",
"revision" : "2016-04-09"
},
{
"name" : "ietf-yang-types",
"revision" : "2013-07-15"
}
]
}
}
}
D.3.4. "insert" Parameter
In this example, a new first song entry in the "Foo-One" playlist is
being created.
Request from client:
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POST /restconf/data/example-jukebox:jukebox/\
playlist=Foo-One?insert=first HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{
"example-jukebox:song" : [
{
"index" : 1,
"id" : "/example-jukebox:jukebox/library\
/artist[name='Foo Figthers']\
/album[name='Wasting Light']\
/song[name=Rope']"
}
]
}
Response from server:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2016 13:01:20 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2016 13:01:20 GMT
Location: https://example.com/restconf/data/\
example-jukebox:jukebox/playlist=Foo-One/song=1
ETag: "eeeada438af"
D.3.5. "point" Parameter
In this example, the client is inserting a new song entry in the
"Foo-One" playlist after the first song.
Request from client:
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POST /restconf/data/example-jukebox:jukebox/\
playlist=Foo-One?insert=after&point=\
%2Fexample-jukebox%3Ajukebox\
%2Fplaylist%3DFoo-One%2Fsong%3D1 HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
{
"example-jukebox:song" : [
{
"index" : 2,
"id" : "/example-jukebox:jukebox/library\
/artist[name='Foo Figthers']\
/album[name='Wasting Light']\
/song[name=Bridge Burning']"
}
]
}
Response from server:
HTTP/1.1 201 Created
Date: Mon, 23 Apr 2016 13:01:20 GMT
Server: example-server
Last-Modified: Mon, 23 Apr 2016 13:01:20 GMT
Location: https://example.com/restconf/data/\
example-jukebox:jukebox/playlist=Foo-One/song=2
ETag: "abcada438af"
D.3.6. "filter" Parameter
The following URIs show some examples of notification filter
specifications:
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// filter = /event/event-class='fault'
GET /streams/NETCONF?filter=%2Fevent%2Fevent-class%3D'fault'
// filter = /event/severity<=4
GET /streams/NETCONF?filter=%2Fevent%2Fseverity%3C%3D4
// filter = /linkUp|/linkDown
GET /streams/SNMP?filter=%2FlinkUp%7C%2FlinkDown
// filter = /*/reporting-entity/card!='Ethernet0'
GET /streams/NETCONF?\
filter=%2F*%2Freporting-entity%2Fcard%21%3D'Ethernet0'
// filter = /*/email-addr[contains(.,'company.com')]
GET /streams/critical-syslog?\
filter=%2F*%2Femail-addr[contains(.%2C'company.com')]
// Note: the module name is used as prefix.
// filter = (/example-mod:event1/name='joe' and
// /example-mod:event1/status='online')
GET /streams/NETCONF?\
filter=(%2Fexample-mod%3Aevent1%2Fname%3D'joe'%20and\
%20%2Fexample-mod%3Aevent1%2Fstatus%3D'online')
// To get notifications from just two modules (e.g., m1 + m2)
// filter=(/m1:* or /m2:*)
GET /streams/NETCONF?filter=(%2Fm1%3A*%20or%20%2Fm2%3A*)
D.3.7. "start-time" Parameter
The following URI shows an example of the "start-time" query
parameter:
// start-time = 2014-10-25T10:02:00Z
GET /streams/NETCONF?start-time=2014-10-25T10%3A02%3A00Z
D.3.8. "stop-time" Parameter
The following URI shows an example of the "stop-time" query
parameter:
// start-time = 2014-10-25T10:02:00Z
// stop-time = 2014-10-25T12:31:00Z
GET /mystreams/NETCONF?start-time=2014-10-25T10%3A02%3A00Z\
&stop-time=2014-10-25T12%3A31%3A00Z
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D.3.9. "with-defaults" Parameter
Assume the server implements the module "example" defined in
Appendix A.1 of [RFC6243]. Assume the server's datastore is as
defined in Appendix A.2 of [RFC6243].
If the server defaults-uri basic-mode is "trim", the the following
request for interface "eth1" might be as follows:
Without query parameter:
GET /restconf/data/example:interfaces/interface=eth1 HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows.
HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"example:interface" : [
{
"name" : "eth1",
"status" : "up"
}
]
}
Note that the "mtu" leaf is missing because it is set to the default
"1500", and the server defaults handling basic-mode is "trim".
With query parameter:
GET /restconf/data/example:interfaces/interface=eth1\
?with-defaults=report-all HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows.
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HTTP/1.1 200 OK
Date: Mon, 23 Apr 2016 17:01:00 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"example:interface" : [
{
"name" : "eth1",
"mtu" : 1500,
"status" : "up"
}
]
}
Note that the server returns the "mtu" leaf because the "report-all"
mode was requested with the "with-defaults" query parameter.
Authors' Addresses
Andy Bierman
YumaWorks
Email: andy@yumaworks.com
Martin Bjorklund
Tail-f Systems
Email: mbj@tail-f.com
Kent Watsen
Juniper Networks
Email: kwatsen@juniper.net
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