Activity Streams (http://activitystrea.ms) J. Snell
Internet-Draft IBM
Intended status: Standards Track M. Marum
Expires: July 30, 2014 SugarCRM
January 26, 2014
JSON Activity Streams 2.0 - Action Handlers
draft-snell-activitystreams-actions-03
Abstract
This specification defines Action Handlers for use with the Activity
Streams 2.0 format.
Author's Note
Note that this document is a work-in-progress draft specification
that does not yet represent a "standard". It is the intention of
this specification to propose a few new ideas and openly solicit
feedback on their definition and use. While this document might
eventually evolve into an RFC the ideas described herein have not yet
been broadly implemented and have definitions that will evolve
through successive iterations of this draft.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 30, 2014.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Action Handlers . . . . . . . . . . . . . . . . . . . . . . . 3
3. HTTP Action Handler . . . . . . . . . . . . . . . . . . . . . 7
4. Embed Action Handler . . . . . . . . . . . . . . . . . . . . 12
5. Intent Action Handler . . . . . . . . . . . . . . . . . . . . 15
6. Using "service" and "application" objects as action handlers 15
7. HTML Form Objects . . . . . . . . . . . . . . . . . . . . . . 16
8. Typed Payload Objects . . . . . . . . . . . . . . . . . . . . 17
9. URL Template Objects . . . . . . . . . . . . . . . . . . . . 19
10. Parameters Object . . . . . . . . . . . . . . . . . . . . . . 20
10.1. Parameter Object . . . . . . . . . . . . . . . . . . . . 21
10.2. Using UrlTemplate and TypedPayload objects as parameter
descriptions . . . . . . . . . . . . . . . . . . . . . . 26
11. Authentication Object . . . . . . . . . . . . . . . . . . . . 27
12. Styles Object . . . . . . . . . . . . . . . . . . . . . . . . 28
13. Security Considerations . . . . . . . . . . . . . . . . . . . 30
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
15. Normative References . . . . . . . . . . . . . . . . . . . . 30
Appendix A. Using Action Handlers From Other Vocabularies . . . 30
A.1. Schema.org Actions Proposal . . . . . . . . . . . . . . . 30
A.2. Google's "Actions in the Inbox" . . . . . . . . . . . . . 31
A.3. Mixing Vocabularies . . . . . . . . . . . . . . . . . . . 32
A.4. Example Drawing From Multiple Vocabularies . . . . . . . 33
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35
1. Overview
The Activity Streams 2.0 [I-D.snell-activitystreams] specification
introduces the notion of "actions" that can be associated with
objects. Using the "actions" property described in Sections 3.6 and
3.6.1 of the Activity Streams 2.0 document, the producer of an object
can declare a specific set of verbs appropriate for the object and
map each of those to one or more objects ("action handlers") or
resources capable of "carrying out" the verb. This document expands
on that mechanism by defining and describing a core set of action
handler object types.
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2. Action Handlers
An action handler is an Activity Streams 2.0 object whose objectType
and member properties instruct a consuming application how to carry
out the verb the action handler has been associated with. For
instance, given the following example:
{
"objectType": "note",
"displayName": "Title of the note",
"content": "This is a simple note.",
"actions": {
"share": {
"objectType": "HttpActionHandler",
"url": "http://example.org/share"
},
"like": {
"objectType": "EmbedActionHandler",
"mediaType": "text/plain",
"content": "Hello World"
}
}
}
The "note" object has two declared actions, "share" and "like". Each
of those is associated with one action handler object. The "share"
action has a action handler of type "HttpActionHandler", while the
"like" action has an "EmbedActionHandler".
As illustrated in the example, action handlers are represented as
Activity Streams 2.0 objects. All such objects share a common set of
base member properties as defined in the following table:
+---------+--------------------------+---------+--------------------+
| Propert | Value | Require | Description |
| y | | d | |
+---------+--------------------------+---------+--------------------+
| confirm | Boolean | No | True if the |
| | | | consuming |
| | | | application ought |
| | | | to seek |
| | | | confirmation prior |
| | | | to using the |
| | | | action handler to |
| | | | carry out it's |
| | | | associated action. |
| | | | Defaults to False. |
| context | JSON Object | No | Contextual |
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| | | | information |
| | | | associated with |
| | | | the action |
| | | | handler, |
| | | | represented as a |
| | | | JSON Object |
| | | | without any |
| | | | particular |
| | | | structure. How the |
| | | | context is used is |
| | | | dependent entirely |
| | | | on the action |
| | | | handler definition |
| | | | and on how a |
| | | | consuming |
| | | | application |
| | | | chooses to |
| | | | implement the |
| | | | action handler. |
| expects | Link Value [I-D.snell-ac | No | For action |
| | tivitystreams] | | handlers with a |
| | | | distinct input |
| | | | requirement (e.g. |
| | | | HttpActionHandler) |
| | | | , the expects |
| | | | property provides |
| | | | a description of |
| | | | the expected |
| | | | input. The value |
| | | | is expressed as |
| | | | either a String |
| | | | containing a fully |
| | | | qualified IRI, an |
| | | | Activity Stream |
| | | | Object, or an |
| | | | Array of IRI's or |
| | | | Objects. When |
| | | | multiple values |
| | | | are provided, they |
| | | | MUST be considered |
| | | | as mutually |
| | | | exclusive |
| | | | alternatives. |
| returns | Link Value [I-D.snell-ac | No | For action |
| | tivitystreams] | | handlers with a |
| | | | distinct output, |
| | | | the returns |
| | | | property provides |
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| | | | a description of |
| | | | the expected |
| | | | output. The value |
| | | | is expressed as |
| | | | either a String |
| | | | containing a fully |
| | | | qualified IRI, an |
| | | | Activity Stream |
| | | | Object, or an |
| | | | Array of IRI's or |
| | | | Objects. When |
| | | | multiple values |
| | | | are provided, they |
| | | | MUST be considered |
| | | | as mutually |
| | | | exclusive |
| | | | alternatives. |
| auth | Authentication Value | No | For action |
| | (Section 11) | | handlers with |
| | | | specific |
| | | | authentication |
| | | | requirements, the |
| | | | "auth" property |
| | | | provides |
| | | | information about |
| | | | the specific |
| | | | authentication |
| | | | mechanisms |
| | | | supported. |
| require | Link Value [I-D.snell-ac | No | An optional Link |
| s | tivitystreams] | | Value whose |
| | | | value(s) describe |
| | | | features or |
| | | | behaviors an |
| | | | implementation |
| | | | MUST support in |
| | | | order to carry out |
| | | | the action. |
| | | | Requirements are |
| | | | designed to be |
| | | | intentionally |
| | | | open-ended and |
| | | | will vary |
| | | | depending on |
| | | | specific Action |
| | | | Handler type. Any |
| | | | implementation |
| | | | that does not |
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| | | | support any |
| | | | specified required |
| | | | feature MUST |
| | | | ignore the Action |
| | | | Handler. |
| prefers | Link Value [I-D.snell-ac | No | An optional Link |
| | tivitystreams] | | Value whose |
| | | | value(s) describe |
| | | | features or |
| | | | behaviors an |
| | | | implementation |
| | | | SHOULD support in |
| | | | order to carry out |
| | | | the action. |
| | | | Requirements are |
| | | | designed to be |
| | | | intentionally |
| | | | open-ended and |
| | | | will vary |
| | | | depending on |
| | | | specific Action |
| | | | Handler type. Any |
| | | | implementation |
| | | | that does not |
| | | | support any |
| | | | specified |
| | | | preferred feature |
| | | | MAY ignore the |
| | | | feature. |
+---------+--------------------------+---------+--------------------+
This specification defines three specific base types of action
handler:
o The HTTP Action Handler (Section 3),
o The Embed Action Handler (Section 4), and
o The Intent Action Handler (Section 5).
Implementations are free to use Activity Stream objects of any
objectType as an action handler. Consuming applications MAY ignore
any object it encounters that use objectTypes that are not recognized
or supported as action handlers. Alternatively, the consuming
application MAY treat such objects as implied Intent Action Handlers
(Section 5).
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Multiple independent action handlers can be associated with any
single verb using a JSON Array. The ordering of objects within such
an array is not considered to be significant.
For example, in the following, the "share" action has two associated
action handlers:
{
"objectType": "event",
"displayName": "Party!",
"content": "We're going to party like it's 1999!",
"id": "urn:example:events:123",
"actions": {
"share": [
{
"objectType": "HttpActionHandler",
"method": "GET",
"url": "http://example.org/share-action",
"target": "DIALOG",
"returns": {
"objectType": "TypedPayload",
"mediaType": "text/html"
}
},
{
"objectType": "EmbedActionHandler",
"mediaType": "text/html",
"content": "...
"
}
]
}
}
3. HTTP Action Handler
An HTTP Action Handler describes an HTTP request/response flow that
is used to carry out an action. It is identified using an objectType
value of "HttpActionHandler".
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+----------+----------------------------+----------+----------------+
| Property | Value | Required | Description |
+----------+----------------------------+----------+----------------+
| url | Link Value | Yes | Specifies the |
| | | | HTTP or HTTPS |
| | | | URL to which |
| | | | the HTTP |
| | | | request is |
| | | | directed. |
| method | HTTP Method String (e.g. | No | The HTTP |
| | "GET", "POST", "PUT", etc) | | method to use. |
| | | | Defaults to |
| | | | "GET" |
| target | "DEFAULT" - Consumer | No | Specifies the |
| | defined default; "NONE" - | | intended |
| | No navigation or UI | | target of the |
| | context (e.g. a hidden | | HTTP action. |
| | HTTP action that does not | | This |
| | result in the creation or | | determines |
| | use of a browser window); | | whether the |
| | "NEW" - A new navigation | | action results |
| | or UI context (e.g. show | | in a new |
| | the results of the HTTP | | navigation |
| | request in a browser | | context (e.g. |
| | window or tab.); "CURRENT" | | new browser |
| | - Reuse the existing | | window) or |
| | navigation or UI context | | whether the |
| | (e.g. show the results of | | action is |
| | the HTTP request in an | | "hidden". When |
| | existing browser window or | | not specified, |
| | tab.); {Other token value} | | defaults to |
| | - Any other TOKEN value. | | "DEFAULT", |
| | Interpretation and support | | meaning that |
| | of such extension tokens | | the consuming |
| | is dependent on the | | application is |
| | consuming application. | | free to |
| | Unknown or unsupported | | determine an |
| | values MUST be ignored. | | appropriate |
| | | | target |
| | | | context. |
+----------+----------------------------+----------+----------------+
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For example:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": {
"objectType": "HttpActionHandler",
"url": "http://example.org/foo",
"method": "GET"
}
}
}
As a shortcut, HttpActionHandlers that use the "GET" method and a
"DEFAULT" target can be specified using a JSON string containing the
absolute URL. For instance:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": "http://example.org/foo"
}
}
In the Activity Streams 2.0 format, the "url" property is defined as
a "Link Value", this means that it is possible for the value of the
"url" property to be an Activity Stream object that a consuming
application can use to resolve the actual target URL. This
specification defines a new UrlTemplate (Section 9) objectType
specifically intended for such use.
The UrlTemplate object can be used within an HTTP Action Handler, for
instance, whenever carrying out the HTTP request requires the
construction of a new URL that includes variable parameters:
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{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"review": {
"objectType": "HttpActionHandler",
"url": {
"objectType": "UrlTemplate",
"method": "POST",
"template": "http://example.org/note/123{?rating}",
"parameters": {
"rating": {
"id": "http://schema.org/ratingValue",
"displayName": "Rating",
"maximum": 5,
"minimum": 1,
"format": "uint32"
}
}
},
"method": "GET",
"target": "NEW"
}
}
}
If the intended HTTP request uses the GET method and DEFAULT target,
the UrlTemplate object itself can be used directly as the action
handler.
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"GET" HttpActionHandler shortcut using a URL Template:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"review": {
"objectType": "UrlTemplate",
"template": "http://example.org/note/123{?rating}",
"parameters": {
"rating": {
"id": "http://schema.org/ratingValue",
"displayName": "Rating",
"maximum": 5,
"minimum": 1,
"format": "uint32"
}
}
}
}
}
If the HTTP request requires an input payload, the HttpActionHandler
object can contain an "expects" property. The value of "expects" is
an Activity Streams 2.0 "Link Value" represented either as a simple
JSON string containing a fully qualified IRI, an Activity Stream
object, or an array of IRI's or Objects. This specification defines
a new HtmlForm (Section 7) objectType to be used whenever the input
of the HTTP request is an HTML Form POST. A new TypedPayload
(Section 8) objectType is defined for use whenever the input is an
arbitrary MIME media type.
For example, the following describes an HTML Form post with a single
"foo" parameter submitted using the "application/x-www-form-
urlencoded" format:
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{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"share": {
"objectType": "HttpActionHandler",
"method": "POST",
"url": "http://example.org/foo",
"expects": {
"objectType": "HtmlForm",
"mediaType": "application/x-www-form-urlencoded",
"parameters": {
"foo": {
"id": "http://example.org/foo",
"type": "http://www.w3.org/2001/XMLSchema#string",
"displayName": "Foo Property"
}
}
}
}
}
}
4. Embed Action Handler
An Embed Action Handler defines static or dynamic content to be
visually rendered to carry out an action. Examples of embeds can
include static HTML, images, videos, gadgets and applications. It is
identified using an objectType value of "EmbedActionHandler".
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+-----------+--------------+--------------+-------------------------+
| Property | Value | Required | Description |
+-----------+--------------+--------------+-------------------------+
| url | Link Value | Yes if | The URL from which to |
| | | "content" is | retrieve the content |
| | | not | for this embed. |
| | | specified. | |
| content | String | Yes if "url" | The character based |
| | | is not | "static" content to be |
| | | specified. | embeded. The |
| | | | "mediaType" parameter |
| | | | specifies the MIME |
| | | | media type of the |
| | | | content. |
| mediaType | MIME Media | No (but | The MIME Media Type of |
| | Type | strongly | the embedded content. |
| | | recommended) | |
| style | Styles | No | Visual CSS styling |
| | Object | | hints to apply to the |
| | (Section 12) | | element containing the |
| | | | embedded content. |
| preview | Link Value | No | A reference to a |
| | | | "preview" |
| | | | representation of the |
| | | | embedded content. |
| | | | Typically, this would a |
| | | | URL to a thumbnail or |
| | | | screenshot image of the |
| | | | content. |
| target | "DEFAULT"; | No | |
| | "INLINE"; | | |
| | {Other token | | |
| | value} | | |
+-----------+--------------+--------------+-------------------------+
In the following example, the "view" action is associated with an
"EmbedActionHandler" containing a static fragment of HTML markup:
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{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": {
"objectType": "EmbedActionHandler",
"content": "This is some bit of embedded HTML
",
"mediaType": "text/html",
"style": {
"height": "100px",
"width": "100px",
"box-shadow": "10px 10px 5px #888888"
},
"displayName": "Some embedded content",
"preview": "http://example.org/preview/123.jpg"
}
}
}
Alternatively, the embedded content can be referenced by URL:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": {
"objectType": "EmbedActionHandler",
"url": "http://example.org/foo",
"mediaType": "text/html"
}
}
}
The mediaType parameter specifies the type of content to be embedded.
Consuming applications MAY ignore Embed Action Handlers that specify
unrecognized or unsupported mediaTypes.
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Example:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": {
"objectType": "EmbedActionHandler",
"url": "http://example.org/foo.mpg",
"mediaType": "video/mpeg"
}
}
}
5. Intent Action Handler
An Intent Action Handler provides a generic way for the publisher of
an Activity object to tell the consuming application to figure out
how to handle the action on it's own. The consumer can, for
instance, pass the object off to some other native platform
application. It is identified using an objectType value of
"IntentActionHandler".
For example:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"share": {
"objectType": "IntentActionHandler",
"displayName": "Share This",
"context": {
"foo": "ABC",
"bar": 123
}
}
}
}
6. Using "service" and "application" objects as action handlers
The "service" and "application" object are existing objectTypes
defined by the Activity Streams 1.0 core schema. While these objects
were not originally designed to be used as action handlers, they can
be. Specifically, the "service" objectType can be used when the
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action is to be carried out using some specific third party service
interface; the "application" objectType can be used when the action
is to be carried out by deferring some some specific native platform
application.
For example:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"share": {
"objectType": "service",
"displayName": "My Sharing Service",
"url": "http://share.example.org/api"
},
"save": {
"objectType": "application",
"displayName": "Read this later!",
"platform": "android",
"id": "123",
"url": "http://play.google.com/..."
}
}
}
7. HTML Form Objects
+----------+-------------+---------+--------------------------------+
| Property | Value | Require | Description |
| | | d | |
+----------+-------------+---------+--------------------------------+
| mediaTyp | MIME Media | No | Defaults to "application/x |
| e | Type | | -www-form-urlencoded" |
| paramete | Parameters | No | Defines the HTML form |
| rs | Object | | parameters. |
| | (Section | | |
| | 10) | | |
+----------+-------------+---------+--------------------------------+
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For example:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"review": {
"objectType": "HttpActionHandler",
"method": "POST",
"url": "http://example.org/foo",
"expects": {
"objectType": "HtmlForm",
"mediaType": "application/x-www-form-urlencoded",
"parameters": {
"foo": {
"displayName": "Foo",
"id": "http://example.org/FooProperty",
"type": "http://www.w3.org/2001/XMLSchema#string",
"required": True
},
"bar": {
"displayName": "Bar",
"id": "http://example.org/BarProperty",
"type": "http://www.w3.org/2001/XMLSchema#",
"required": True,
"value": "Provided Value"
}
}
}
}
}
}
8. Typed Payload Objects
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+----------+-----------------------------+----------+---------------+
| Property | Value | Required | Description |
+----------+-----------------------------+----------+---------------+
| mediaTyp | MIME Media Type | Yes | The MIME |
| e | | | Media Type of |
| | | | the Payload |
| type | Type Value | No | An optional |
| | [I-D.snell-activitystreams] | | Type Value |
| | | | that |
| | | | describes the |
| | | | payloads |
| | | | semantic |
| | | | type. |
| schema | Link Value | No | An optional |
| | [I-D.snell-activitystreams] | | Link Value |
| | | | whose |
| | | | value(s) |
| | | | describe the |
| | | | structure of |
| | | | the payload |
| | | | data. The |
| | | | value is |
| | | | represented |
| | | | either as a |
| | | | String with a |
| | | | fully |
| | | | qualified |
| | | | IRI, an |
| | | | Activity |
| | | | Stream |
| | | | object, or an |
| | | | Array of IRIs |
| | | | and Objects. |
| | | | If multiple |
| | | | values are |
| | | | provided, |
| | | | they are to |
| | | | be considered |
| | | | mutually |
| | | | exclusive |
| | | | alternatives. |
+----------+-----------------------------+----------+---------------+
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For example:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"review": {
"objectType": "HttpActionHandler",
"method": "POST",
"url": "http://example.org/foo",
"expects": {
"objectType": "TypedPayload",
"mediaType": "text/json",
}
}
}
}
9. URL Template Objects
Objects with the "UrlTemplate" object type represent [RFC6570] URL
Templates.
+------------+--------------------+----------+----------------------+
| Property | Value | Required | Description |
+------------+--------------------+----------+----------------------+
| template | URL Template | Yes | The [RFC6570] URL |
| | | | Template |
| parameters | Parameters Object | No | Defines the URL |
| | (Section 10) | | Template parameters |
+------------+--------------------+----------+----------------------+
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{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"review": {
"objectType": "UrlTemplate",
"template": "http://example.org/foo/123{?rating}",
"parameters": {
"rating": {
"displayName": "Rating",
"id": "http://example.org/RatingProperty",
"required": True
}
}
}
}
}
10. Parameters Object
A Parameters Object is used to provide descriptions of the variable
inputs of objects such as HTML Forms (Section 7) and URL Templates
(Section 9). The object is expressed as a JSON dictionary mapping
parameter names to Type Values [I-D.snell-activitystreams] describing
the parameters.
By default, all parameters defined within the object are assumed to
be required. When a parameter is described using an Object, the
object MAY contained a boolean "required" member. If "required" is
false, use of the parameter is assumed to be optional.
Using the Parameters Object in UrlTemplate objects:
{
"objectType": "UrlTemplate",
"template": "http://example.org{/foo,bar}"
"parameters": {
"foo": "http://example.org/FooProperty",
"bar": {
"id": "http://example.org/BarProperty",
"displayName": "Bar",
"required": False
}
}
}
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Using the Parameters Object in HtmlForm objects:
{
"objectType": "HtmlForm",
"mediaType": "application/x-www-form-urlencoded",
"parameters": {
"foo": "http://example.org/FooProperty",
"bar": {
"objectType": "parameter",
"id": "http://example.org/BarProperty",
"displayName": "Bar",
"required": False
}
}
}
This specification defines a Parameter objectType (Section 10.1)
specifically designed to describe parameters.
Implementations that encounter unrecognized or unexpected objectTypes
used to describe parameters will likely be unable to successfully
comprehend the parameter and may, therefore, be unable to carry out
an Action.
10.1. Parameter Object
The "parameter" objectType is specifically intended for use with the
Parameters (Section 10) object. Each Parameter object provides a
rich description of a single parameter.
+------------+--------------------------+----------+----------------+
| Property | Value | Required | Description |
+------------+--------------------------+----------+----------------+
| required | boolean | No | True if the |
| | | | parameter is |
| | | | required. |
| | | | Defaults to |
| | | | true. |
| repeated | boolean | No | True if the |
| | | | parameter can |
| | | | be repeated |
| | | | zero or more |
| | | | times. |
| value | (Any) | No | Provides a |
| | | | fixed value |
| | | | for the |
| | | | parameter. |
| | | | When |
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| | | | specified, imp |
| | | | lementations |
| | | | MUST use the |
| | | | specified |
| | | | value. |
| default | (Any) | No | Provides a |
| | | | default value |
| | | | for the |
| | | | parameter. |
| | | | When |
| | | | specified, imp |
| | | | lementations |
| | | | MUST use the |
| | | | specified |
| | | | value if no |
| | | | other value is |
| | | | not supplied. |
| enum | Array of (Any) | No | Provides a |
| | | | fixed array of |
| | | | possible |
| | | | values for the |
| | | | parameter. |
| | | | When |
| | | | specified, imp |
| | | | lementations |
| | | | MUST use one |
| | | | of the |
| | | | specified |
| | | | values. |
| maximum | (Any) | No | A value that |
| | | | is considered |
| | | | to be the |
| | | | upper bound of |
| | | | a range of |
| | | | possible |
| | | | values. This |
| | | | would |
| | | | typically be |
| | | | used only with |
| | | | numeric |
| | | | parameters. |
| minimum | (Any) | No | A value that |
| | | | is considered |
| | | | to be the |
| | | | lower bound of |
| | | | a range of |
| | | | possible |
| | | | values. This |
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| | | | would |
| | | | typically be |
| | | | used only with |
| | | | numeric |
| | | | parameters. |
| step | Non-negative Number | No | Specifies the |
| | | | legal numeric |
| | | | interval |
| | | | between |
| | | | acceptable |
| | | | values for the |
| | | | parameter. The |
| | | | step value |
| | | | MUST be a |
| | | | number and |
| | | | MUST conform |
| | | | to the given |
| | | | format if a |
| | | | format is |
| | | | specified. For |
| | | | instance, if |
| | | | format is |
| | | | "uint32", then |
| | | | step=2 would |
| | | | indicate legal |
| | | | values of 0, |
| | | | 2, 4, 6, and |
| | | | so on. The |
| | | | step property |
| | | | MAY be ignored |
| | | | if it's value |
| | | | does not |
| | | | correspond to |
| | | | the expected |
| | | | format. |
| format | String | No | A string that |
| | | | describes the |
| | | | format of the |
| | | | value. The |
| | | | format can be |
| | | | one of the |
| | | | list of |
| | | | standard |
| | | | formats listed |
| | | | below or any |
| | | | other string. |
| | | | If an |
| | | | implementation |
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| | | | encounters a |
| | | | format string |
| | | | it does not |
| | | | recognize, the |
| | | | format |
| | | | property MAY |
| | | | be ignored. |
| | | | When not |
| | | | specified, the |
| | | | value format |
| | | | is assumed to |
| | | | be a sequence |
| | | | of UTF-8 |
| | | | encoded |
| | | | codepoints. |
| pattern | String | No | A Regular |
| | | | Expression |
| | | | that describes |
| | | | the structure |
| | | | of the value. |
| | | | Typically used |
| | | | when the value |
| | | | is a string. |
| placeholde | Natural Language Value [ | No | An optional |
| r | I-D.snell-activitystream | | Natural |
| | s] | | Language Value |
| | | | providing a |
| | | | text hint that |
| | | | describes the |
| | | | expected value |
| | | | of the |
| | | | parameter. |
+------------+--------------------------+----------+----------------+
The following common format strings MAY be used as values for the
"format" property:
o "boolean" - Specifies that the value is either a string specifying
"true" or "false", a boolean True or False, or an integer where 0
represents False and any other value represents True.
o "byte" - Specifies that the value is a "URL and filename safe"
Base64-encoded string of bytes as defined by [RFC4648].
o "hex" - Specifies that the value is a String containing a sequence
of Hex-encoded bytes.
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o "date" - Specifies that the value is a "full-date" (YYYY-MM-DD) as
defined by [RFC3339].
o "date-time" - Specifies that the value is a "date-time" as defined
by [RFC3339].
o "double" - Specifies that the value is a double-precision 64-bit
IEEE 754 floating point value.
o "duration" - Specifies that the value is a "duration" as defined
by [RFC3339].
o "float" - Specifies that the value is a single-precision 32-bit
IEEE 754 floating point.
o "int32" - Specifies that the value is a signed, 32-bit integer in
the range -2,147,483,648 to 2,147,483,647 (inclusive).
o "int64" - Specifies that the value is a signed, 64-bit integer in
the range -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
(inclusive).
o "uint32" - Specifies that the value is an unsigned 32-bit integer
in the range 0 to 4,294,967,295 (inclusive).
o "uint64" - Specifies that the value is an unsigned 64-bit integer
in the range 0 to (2^64)-1 (inclusive)
o "lang" - Specifies that the value is a Language Tag as defined by
[RFC5646].
o "uri" - Specifies that the value is a string containing a URI as
defined by [RFC3986].
o "iri" - Specifies that the value is a string containing an IRI as
defined by [RFC3987].
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Using the Parameter Object in HtmlForm objects:
{
"objectType": "HtmlForm",
"mediaType": "application/x-www-form-urlencoded",
"parameters": {
"foo": "http://example.org/FooProperty",
"bar": {
"objectType": "parameter",
"id": "http://example.org/BarProperty",
"displayName": "Bar",
"required": False,
"repeated": False,
"format": "uint32",
"defaultValue": 3,
"minimum": 1,
"maximum": 5
}
}
}
10.2. Using UrlTemplate and TypedPayload objects as parameter
descriptions
In certain cases, when the value of a parameter is expected to be
either a URI or IRI, the UrlTemplate objectType (Section 9) MAY be
used as the parameter description. In such cases, the "required",
"repeated", "default" and "placeholder" properties from the Parameter
objectType (Section 10.1) can be used as additional properties within
the UrlTemplate object.
For example:
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{
"objectType": "HtmlForm",
"mediaType": "application/x-www-form-urlencoded",
"parameters": {
"foo": "http://example.org/FooProperty",
"bar": {
"objectType": "UrlTemplate",
"id": "http://example.org/BarProperty",
"template": "http://example.org{/foo}",
"parameters": {
"foo": "http://example.org/#string"
},
"displayName": "Bar",
"required": False,
"repeated": False
}
}
}
Likewise, when the value of a parameter is expected to be an instance
of a specific MIME media type, the TypedPayload objectType
(Section 8) can be used.
{
"objectType": "HtmlForm",
"mediaType": "multipart/form-data",
"parameters": {
"file": {
"objectType": "TypedPayload",
"mediaType": "image/*",
"required": True,
"repeated": True
}
}
}
11. Authentication Object
An Authentication Object is used by Action Handlers that require
specific authentication options to be supported in order to carry out
the Action. The object is expresed as a JSON dictionary mapping
authentication schema labels to JSON dictionaries that provide a
specific description of properties and requirements specific to the
scheme.
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Example Authentication details:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note",
"actions": {
"view": {
"objectType": "HttpActionHandler",
"method": "GET",
"url": "http://example.org/notes/1",
"auth": {
"basic": {
"realm": "http://example.org"
},
"oauth": {
"scopes": [
"some.oauth.scope",
"another.oauth.scope"
]
}
}
}
}
}
This specification does not define the authentication schemes or
their associated properties. Unrecognized authentication schemes MAY
be ignored. However, if an implementation fails to recognize any of
the authentication schemes specified by an Action Handler, it might
not be possible to successfully carry out the Action.
12. Styles Object
A Styles Object is used by EmbedActionHandlers to provide CSS style
hints for the container within which embedded content is to be
displayed. The object is expressed as either a single JSON
dictionary object mapping CSS property names to appropriate CSS
values, or an array of JSON dictionary objects. An optional "media"
member can be included within the dictionary providing a CSS Media
Query.
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Example style hints:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": {
"objectType": "EmbedActionHandler",
"content": "Some plain text content",
"mediaType": "text/plain",
"style": {
"height": "100px",
"width": "100px",
"box-shadow": "10px 10px 5px #888888"
}
}
}
}
Multiple style hints for specific media query targets:
{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"view": {
"objectType": "EmbedActionHandler",
"content": "Some plain text content",
"mediaType": "text/plain",
"style": [
{
"media": "print",
"height": "100px",
"width": "100px",
"box-shadow": "10px 10px 5px #888888"
},
{
"media": "screen and (orientation: landscape)",
"height": "100px",
"width": "100px",
"box-shadow": "10px 10px 5px #888888"
}
]
}
}
}
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13. Security Considerations
TBD
14. IANA Considerations
TBD
15. Normative References
[I-D.snell-activitystreams]
Snell, J., "JSON Activity Streams 2.0", draft-snell-
activitystreams-05 (work in progress), November 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.
[RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
Identifiers (IRIs)", RFC 3987, January 2005.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006.
[RFC5646] Phillips, A. and M. Davis, "Tags for Identifying
Languages", BCP 47, RFC 5646, September 2009.
[RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M.,
and D. Orchard, "URI Template", RFC 6570, March 2012.
Appendix A. Using Action Handlers From Other Vocabularies
The Activity Streams 2.0 Actions mechanism is specifically designed
to allow Action Handlers from multiple vocabularies.
A.1. Schema.org Actions Proposal
Based on http://www.w3.org/wiki/images/b/b9/Actionsinschema.org.pdf:
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{
"objectType": "video",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"watch": [
{
"objectType": "http://schema.org/WebPageHandler",
"url": "http://movies.example.com/player?id=123"
},
{
"objectType": "http://schema.org/AndroidHandler",
"url": "http://movies.example.com/player?id=123",
"package": "com.movies"
}
]
}
}
A.2. Google's "Actions in the Inbox"
Based on https://developers.google.com/gmail/actions/reference/
review-action:
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{
"objectType": "note",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"review": {
"objectType": "http://schema.org/ReviewAction",
"review": {
"objectType": "http://schema.org/Review",
"itemReviewed": {
"objectType": "http://schema.org/FoodEstablishment",
"name": "Joe's Diner"
},
"reviewRating": {
"objectType": "http://schema.org/Rating",
"bestRating": "5",
"worstRating": "1"
}
},
"handler": {
"objectType": "http://schema.org/HttpActionHandler",
"url": "http://reviews.com/review?id=123",
"requiredProperty": {
"objectType": "http://schema.org/Property",
"name": "review.reviewRating.ratingValue"
},
"method": "http://schema.org/HttpRequestMethod/POST"
}
}
}
}
A.3. Mixing Vocabularies
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{
"objectType": "video",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"watch": [
{
"objectType": "HttpActionHandler",
"url": "http://movies.example.com/player?id=123",
"target": "NEW"
},
{
"objectType": "http://schema.org/AndroidHandler",
"url": "http://movies.example.com/player?id=123",
"package": "com.movies"
}
]
}
}
A.4. Example Drawing From Multiple Vocabularies
{
"objectType": "video",
"displayName": "A Movie!",
"displayName": "A simple note object",
"content": "This is a simple note.",
"actions": {
"watch": [
{
"objectType": "EmbedActionHandler",
"displayName": "HD",
"mediaType": "video/mpeg",
"url": "http://cdn.example.org?id=123amp;fmt=HD",
},
{
"objectType": "EmbedActionHandler",
"displayName": "SD",
"mediaType": "video/mpeg",
"url": "http://cdn.example.org?id=123&fmt=SD",
},
{
"objectType": "application",
"displayName": "Watch on Netflix",
"url": "http://netflix.com..."
}
],
"like": {
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"objectType": "EmbedActionHandler",
"mediaType": "text/html",
"url": "http://www.facebook.com/plugins/like.php...",
"style": {
"width": "150px",
"height": "50px"
}
},
"share": [
{
"objectType": "HttpActionHandler",
"displayName": "Twitter",
"url": "https://twitter.com/share?url=...",
"target": "DIALOG"
},
{
"objectType": "HttpActionHandler",
"displayName": "Facebook",
"url": "https://www.facebook.com/sharer/sharer.php?u=...",
"target": "DIALOG"
}
],
"save": [
{
"objectType": "service",
"id": "http://getpocket.com",
"displayName": "Pocket",
"context": {
"url": "http://example.org/movie?id=123",
"title": "A Movie!",
"tags": "foo, bar, baz"
}
},
{
"objectType": "service",
"id": "http://instapaper.com",
"displayName": "Instapaper",
"context": {
"url": "http://example.org/movie?id=123",
"title": "A Movie!",
"selection": "An action movie!"
}
}
],
"review": {
"objectType": "HttpActionHandler",
"displayName": "Rate this movie!",
"url": "http://review.example.org/movie?id=123",
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"method": "POST",
"expects": {
"objectType": "HtmlForm",
"mediaType": "application/x-www-form-urlencoded",
"parameters": {
"rating": {
"id": "http://schema.org/ratingValue",
"maximum": 5,
"minimum": 0,
"format": "uint32",
"displayName": "Rating",
"required": true
},
"comments": {
"id": "http://schema.org/commentText",
"displayName": "Comments",
"required": "false"
}
}
}
}
}
}
Authors' Addresses
James M Snell
IBM
Email: jasnell@gmail.com
Matthew Marum
SugarCRM
Email: mgmarum@gmail.com
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