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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Newton 3 Internet-Draft ARIN 4 Intended status: Standards Track B. Ellacott 5 Expires: February 8, 2015 APNIC 6 N. Kong 7 CNNIC 8 August 7, 2014 10 HTTP usage in the Registration Data Access Protocol (RDAP) 11 draft-ietf-weirds-using-http-09 13 Abstract 15 This document is one of a collection that together describe the 16 Registration Data Access Protocol (RDAP). It describes how RDAP is 17 transported using the Hypertext Transfer Protocol (HTTP). 19 Normative Reference Note 21 Normative references to RFC 7231 and draft-ietf-httpbis-http2 can be 22 replaced with a reference to RFC 2616 if draft-ietf-httpbis-http2 is 23 still a work in progress when this document is ready for publication. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at http://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on February 8, 2015. 42 Copyright Notice 44 Copyright (c) 2014 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 3. Design Intents . . . . . . . . . . . . . . . . . . . . . . . 4 62 4. Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 63 4.1. Accept Header . . . . . . . . . . . . . . . . . . . . . . 5 64 4.2. Query Parameters . . . . . . . . . . . . . . . . . . . . 5 65 5. Types of HTTP Response . . . . . . . . . . . . . . . . . . . 5 66 5.1. Positive Answers . . . . . . . . . . . . . . . . . . . . 5 67 5.2. Redirects . . . . . . . . . . . . . . . . . . . . . . . . 5 68 5.3. Negative Answers . . . . . . . . . . . . . . . . . . . . 6 69 5.4. Malformed Queries . . . . . . . . . . . . . . . . . . . . 6 70 5.5. Rate Limits . . . . . . . . . . . . . . . . . . . . . . . 6 71 5.6. Cross-Origin Resource Sharing . . . . . . . . . . . . . . 7 72 6. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 7 73 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 74 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 75 8.1. RDAP Extensions Registry . . . . . . . . . . . . . . . . 8 76 9. Internationalization Considerations . . . . . . . . . . . . . 9 77 9.1. URIs and IRIs . . . . . . . . . . . . . . . . . . . . . . 9 78 9.2. Language Identifiers in Queries and Responses . . . . . . 9 79 9.3. Language Identifiers in HTTP Headers . . . . . . . . . . 9 80 10. Contributing Authors and Acknowledgements . . . . . . . . . . 9 81 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 82 11.1. Normative References . . . . . . . . . . . . . . . . . . 10 83 11.2. Informative References . . . . . . . . . . . . . . . . . 10 84 Appendix A. Protocol Example . . . . . . . . . . . . . . . . . . 11 85 Appendix B. Cache Busting . . . . . . . . . . . . . . . . . . . 11 86 Appendix C. Changelog . . . . . . . . . . . . . . . . . . . . . 12 87 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 89 1. Introduction 91 This document describes the usage of HTT[RFC7231]P for Registration 92 Data Directory Services. The goal of this document is to tie 93 together usage patterns of HTTP into a common profile applicable to 94 the various types of Directory Services serving Registration Data 95 using RESTful practices. By giving the various Directory Services 96 common behavior, a single client is better able to retrieve data from 97 Directory Services adhering to this behavior. 99 The registration data expected to be presented by this service is 100 Internet resource registration data - registration of domain names 101 and Internet number resources. This data is typically provided by 102 WHOIS [RFC3912] services, but the WHOIS protocol is insufficient to 103 modern registration data service requirements. A replacement 104 protocol is expected to retain the simple transactional nature of 105 WHOIS, while providing a specification for queries and responses, 106 redirection to authoritative sources, support for Internationalized 107 Domain Names (IDNs, [RFC5890]), and support for localized 108 registration data such as addresses and organisation or person names. 110 In designing these common usage patterns, this document introduces 111 considerations for a simple use of HTTP. Where complexity may 112 reside, it is the goal of this document to place it upon the server 113 and to keep the client as simple as possible. A client 114 implementation should be possible using common operating system 115 scripting tools. 117 This is the basic usage pattern for this protocol: 119 1. A client issues an HTTP query using GE[I-D.ietf-httpbis-http2]T. 120 As an example, a query for the network registration 192.0.2.0 121 might be http://example.com/ip/192.0.2.0. 123 2. If the receiving server has the information for the query, it 124 examines the Accept header field of the query and returns a 200 125 response with a response entity appropriate for the requested 126 format. 128 3. If the receiving server does not have the information for the 129 query but does have knowledge of where the information can be 130 found, it will return a redirection response (3xx) with the 131 Location: header field containing an HTTP(S) URL (Uniform 132 Resource Locator) pointing to the information or another server 133 known to have knowledge of the location of the information. The 134 client is expected to re-query using that HTTP URL. 136 4. If the receiving server does not have the information being 137 requested and does not have knowledge of where the information 138 can be found, it returns a 404 response. 140 5. If the receiving server will not answer a request for policy 141 reasons, it will return an error response (4xx) indicating the 142 reason for giving no answer. 144 It is important to note that it is not the intent of this document to 145 redefine the meaning and semantics of HTTP. The purpose of this 146 document is to clarify the use of standard HTTP mechanisms for this 147 application. 149 2. Terminology 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 153 document are to be interpreted as described in RFC 2119 [RFC2119]. 155 As is noted in SSAC Report on WHOIS Terminology and Structure 156 [SAC-051], the term "WHOIS" is overloaded, often referring to a 157 protocol, a service and data. In accordance with [SAC-051], this 158 document describes the base behavior for a Registration Data Access 159 Protocol (RDAP). [SAC-051] describes a protocol profile of RDAP for 160 Domain Name Registries (DNRs), the Domain Name Registration Data 161 Access Protocol (DNRD-AP). 163 In this document, an RDAP client is an HTTP User Agent performing an 164 RDAP query, and an RDAP server is an HTTP server providing an RDAP 165 response. RDAP query and response formats are described in other 166 documents in the collection of RDAP specifications, while this 167 document describes how RDAP clients and servers use HTTP to exchange 168 queries and responses. 170 3. Design Intents 172 There are a few design criteria this document attempts to meet. 174 First, each query is meant to return either zero or one result. With 175 the maximum upper bound being set to one, the issuance of redirects 176 is simplified to the traditional query/response model used by HTTP 177 [RFC7231]. Should an entity contain more than one result, some of 178 which are better served by other servers, the redirection model 179 becomes much more complicated. 181 Second, the semantics of the request/response allow for future and/or 182 non-standard response formats. In this document, only a JSON 183 [RFC4627] response media type is noted, with the response contents to 184 be described separately. This document only describes how RDAP is 185 transported using HTTP with this format. 187 Third, this protocol is intended to be able to make use of the range 188 of mechanisms available for use with HTTP. HTTP offers a number of 189 mechanisms not described further in this document. Operators are 190 able to make use of these mechanisms according to their local policy, 191 including cache control, authorization, compression, and redirection. 193 HTTP also benefits from widespread investment in scalability, 194 reliability, and performance, and widespread programmer understanding 195 of client behaviours for RESTful web services, reducing the cost to 196 deploy Registration Data Directory Services and clients. 198 4. Queries 200 4.1. Accept Header 202 To indicate to servers that an RDAP response is desired, clients 203 include an Accept: header field with an RDAP specific JSON media 204 type, the generic JSON media type, or both. Servers receiving an 205 RDAP request return an entity with a Content-Type: header containing 206 the RDAP specific JSON media type. 208 This specification does not define the responses a server returns to 209 a request with any other media types in the Accept: header field, or 210 with no Accept: header field. One possibility would be to return a 211 response in a media type suitable for rendering in a web browser. 213 4.2. Query Parameters 215 Servers MUST ignore unknown query parameters. Use of unknown query 216 parameters for cache-busting is described in Appendix B. 218 5. Types of HTTP Response 220 This section describes the various types of responses a server may 221 send to a client. While no standard HTTP response code is forbidden 222 in usage, at a minimum clients SHOULD understand the response codes 223 described in this section as they will be in common use by servers. 224 It is expected that usage of response codes and types for this 225 application not defined here will be described in subsequent 226 documents. 228 5.1. Positive Answers 230 If a server has the information requested by the client and wishes to 231 respond to the client with the information according to its policies, 232 it returns that answer in the body of a 200 response. 234 5.2. Redirects 236 If a server wishes to inform a client that the answer to a given 237 query can be found elsewhere, it returns either a 301 response code 238 to indicate a permanent move, or a 302, 303 or 307 response code to 239 indicate a non-permanent redirection, and it includes an HTTP(s) URL 240 in the Location: header field. The client is expected to issue a 241 subsequent request to satisfy the original query using the given URL 242 without any processing of the URL. In other words, the server is to 243 hand back a complete URL and the client should not have to transform 244 the URL to follow it. 246 For this application, such an example of a permanent move might be a 247 Top Level Domain (TLD) operator informing a client the information 248 being sought can be found with another TLD operator (i.e. a query for 249 the domain bar in foo.example is found at http://foo.example/domain/ 250 bar). 252 For example, if the client sends 253 http://serv1.example.com/weirds/domain/example.com, the server 254 redirecting to https://serv2.example.net/weirds2/ would set the 255 Location: field to the value: 256 https://serv2.example.net/weirds2/domain/example.com. 258 5.3. Negative Answers 260 If a server wishes to respond that it has an empty result set, it 261 returns a 404 response code. Optionally, it MAY include additional 262 information regarding the negative answer in the HTTP entity body. 264 If a server wishes to inform the client that information about the 265 query is available, but cannot include the information in the 266 response to the client for policy reasons, the server MUST respond 267 with an appropriate response code out of HTTP's 4xx range. Clients 268 MAY retry the query based on the respective response code. 270 5.4. Malformed Queries 272 If a server receives a query which it cannot interpret as an RDAP 273 query, it returns a 400 response code. Optionally, it MAY include 274 additional information regarding this negative answer in the HTTP 275 entity body. 277 5.5. Rate Limits 279 Some servers apply rate limits to deter address scraping and other 280 abuses. When a server declines to answer a query due to rate limits, 281 it returns a 429 response code as described in [RFC6585]. A client 282 that receives a 429 response SHOULD decrease its query rate, and 283 honor the Retry-After header field if one is present. 285 Note that this is not a defense against denial-of-service attacks, 286 since a malicious client could ignore the code and continue to send 287 queries at a high rate. A server might use another response code if 288 it did not wish to reveal to a client that rate limiting is the 289 reason for the denial of a reply. 291 5.6. Cross-Origin Resource Sharing 293 When responding to queries, it is RECOMMENDED that servers use the 294 Access-Control-Allow-Origin header field, as specified by 295 [W3C.CR-cors-20130129]. 297 6. Extensibility 299 For extensibility purposes, this document defines an IANA registry 300 for prefixes used in JSON [RFC4627] data serialization and URI path 301 segments (see Section 8). 303 Prefixes and identifiers SHOULD only consist of the alphabetic ASCII 304 characters A through Z in both uppercase and lowercase, the numerical 305 digits 0 through 9, underscore characters, and SHOULD NOT begin with 306 an underscore character, numerical digit or the characters "xml". 307 The following describes the production of JSON names in ABNF 308 [RFC5234]. 310 ABNF for JSON names 312 name = ALPHA *( ALPHA / DIGIT / "_" ) 314 Figure 1 316 This restriction is a union of the Ruby programming language 317 identifier syntax and the XML element name syntax and has two 318 purposes. First, client implementers using modern programming 319 languages such as Ruby or Java can use libraries that automatically 320 promote JSON names to first order object attributes or members. 321 Second, a clean mapping between JSON and XML is easy to accomplish 322 using these rules. 324 7. Security Considerations 326 This document does not pose strong security requirements to the RDAP 327 protocol. However, it does not restrict against the use of security 328 mechanisms offered by the HTTP protocol. 330 This document made recommendations for server implementations against 331 denial-of-service (Section 5.5) and interoperability with existing 332 security mechanism in HTTP clients (Section 5.6). 334 Additional security considerations to the RDAP protocol will be 335 covered in future RFCs documenting specific security mechanisms and 336 schemes. 338 8. IANA Considerations 340 8.1. RDAP Extensions Registry 342 This specification proposes an IANA registry for RDAP extensions. 343 The purpose of this registry is to ensure uniqueness of extension 344 identifiers. The extension identifier is used as a prefix in JSON 345 names and as a prefix of path segments in RDAP URLs. 347 The production rule for these identifiers is specified in Section 6. 349 In accordance with RFC5226, the IANA policy for assigning new values 350 shall be Specification Required: values and their meanings must be 351 documented in an RFC or in some other permanent and readily available 352 reference, in sufficient detail that interoperability between 353 independent implementations is possible. 355 The following is a preliminary template for an RDAP extension 356 registration: 358 Extension identifier: the identifier of the extension 360 Registry operator: the name of the registry operator 362 Published specification: RFC number, bibliographical reference or 363 URL to a permanent and readily available specification 365 Person & email address to contact for further information: The 366 names and email addresses of individuals for contact regarding 367 this registry entry 369 Intended usage: brief reasons for this registry entry 371 The following is an example of a registration in the RDAP extension 372 registry: 374 Extension identifier: lunarNic 376 Registry operator: The Registry of the Moon, LLC 378 Published specification: http://www.example/moon_apis/rdap 380 Person & email address to contact for further information: 381 Professor Bernardo de la Paz 382 Intended usage: COMMON 384 9. Internationalization Considerations 386 9.1. URIs and IRIs 388 Clients can use IRIs [RFC3987] for internal use as they see fit, but 389 MUST transform them to URIs [RFC3986] for interaction with RDAP 390 servers. RDAP servers MUST use URIs in all responses, and again 391 clients can transform these URIs to IRIs for internal use as they see 392 fit. 394 9.2. Language Identifiers in Queries and Responses 396 Under most scenarios, clients requesting data will not signal that 397 the data be returned in a particular language or script. On the 398 other hand, when servers return data and have knowledge that the data 399 is in a language or script, the data SHOULD be annotated with 400 language identifiers whenever they are available, thus allowing 401 clients to process and display the data accordingly. 403 The mechanism for including a language identifier in a response will 404 be defined in subsequent documents describing specific response 405 formats. 407 9.3. Language Identifiers in HTTP Headers 409 Given the description of the use of language identifiers in 410 Section 9.2, unless otherwise specified servers SHOULD ignore the 411 HTTP [RFC7231] Accept-Language header field when formulating HTTP 412 entity responses, so that clients do not conflate the Accept-Language 413 header with the 'lang' values in the entity body. 415 However, servers MAY return language identifiers in the Content- 416 Language header field so as to inform clients of the intended 417 language of HTTP layer messages. 419 10. Contributing Authors and Acknowledgements 421 John Levine provided text to tighten up the Accept header field usage 422 and the text for the section on 429 responses. 424 Marc Blanchet provided some clarifying text regarding the use of URLs 425 with redirects, as well as very useful feedback during WGLC. 427 Normative language reviews were provided by Murray S. Kucherawy and 428 Andrew Sullivan. 430 Jean-Phillipe Dionne provided text for the Security Considerations 431 section. 433 11. References 435 11.1. Normative References 437 [I-D.ietf-httpbis-http2] 438 Belshe, M., Peon, R., and M. Thomson, "Hypertext Transfer 439 Protocol version 2", draft-ietf-httpbis-http2-14 (work in 440 progress), July 2014. 442 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 443 Requirement Levels", BCP 14, RFC 2119, March 1997. 445 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 446 Resource Identifier (URI): Generic Syntax", STD 66, RFC 447 3986, January 2005. 449 [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource 450 Identifiers (IRIs)", RFC 3987, January 2005. 452 [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status 453 Codes", RFC 6585, April 2012. 455 [RFC7231] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 456 (HTTP/1.1): Semantics and Content", RFC 7231, June 2014. 458 [W3C.CR-cors-20130129] 459 Kesteren, A., "Cross-Origin Resource Sharing", World Wide 460 Web Consortium Candidate Recommendation CR-cors-20130129, 461 January 2013, 462 . 464 11.2. Informative References 466 [RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912, 467 September 2004. 469 [RFC4627] Crockford, D., "The application/json Media Type for 470 JavaScript Object Notation (JSON)", RFC 4627, July 2006. 472 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 473 Specifications: ABNF", STD 68, RFC 5234, January 2008. 475 [RFC5890] Klensin, J., "Internationalized Domain Names for 476 Applications (IDNA): Definitions and Document Framework", 477 RFC 5890, August 2010. 479 [SAC-051] Piscitello, D., Ed., "SSAC Report on Domain Name WHOIS 480 Terminology and Structure", September 2011. 482 Appendix A. Protocol Example 484 To demonstrate typical behaviour of an RDAP client and server, the 485 following is an example of an exchange, including a redirect. The 486 data in the response has been elided for brevity, as the data format 487 is not described in this document. 489 An example of an RDAP client and server exchange: 491 Client: 492 493 GET /ip/203.0.113.0/24 HTTP/1.1 494 Host: rdap.example.com 495 Accept: application/rdap+json 497 rdap.example.com: 498 HTTP/1.1 301 Moved Permanently 499 Location: http://rdap-ip.example.com/ip/203.0.113.0/24 500 Content-Length: 0 501 Content-Type: application/rdap+json 502 504 Client: 505 506 GET /ip/203.0.113.0/24 HTTP/1.1 507 Host: rdap-ip.example.com 508 Accept: application/rdap+json 510 rdap-ip.example.com: 511 HTTP/1.1 200 OK 512 Content-Type: application/rdap+json 513 Content-Length: 9001 515 { ... } 516 518 Appendix B. Cache Busting 520 Some HTTP [RFC7231] cache infrastructure does not adhere to caching 521 standards adequately, and could cache responses longer than is 522 intended by the server. To overcome these issues, clients can use an 523 adhoc and improbably used query parameter with a random value of 524 their choosing. As Section 4.2 instructs servers to ignore unknown 525 parameters, this is unlikely to have any known side effects. 527 An example of using an unknown query parameter to bust caches: 529 http://example.com/ip/192.0.2.0?__fuhgetaboutit=xyz123 531 Use of an unknown parameter to overcome misbehaving caches is not 532 part of any specification and is offered here for informational 533 purposes. 535 Appendix C. Changelog 537 RFC Editor: Please remove this section. 539 Initial WG -00: Updated to working group document 2012-September-20 541 -01 543 * Updated for the sections moved to the JSON responses draft. 545 * Simplified media type, removed "level" parameter. 547 * Updated 2119 language and added boilerplate. 549 * In section 1, noted that redirects can go to redirect servers 550 as well. 552 * Added Section 9.2 and Section 9.3. 554 -02 556 * Added a section on 429 response codes. 558 * Changed Accept header language in section 4.1 560 * Removed reference to the now dead requirements draft. 562 * Added contributing authors and acknowledgements section. 564 * Added some clarifying text regarding complete URLs in the 565 redirect section. 567 * Changed media type to application/rdap+json 569 * Added media type registration 571 -03 573 * Removed forward reference to draft-ietf-weirds-json-response. 575 * Added reference and recommended usage of CORS 577 -04 579 * Revised introduction and abstract. 581 * Added negative responses other than 404. 583 * Added security considerations. 585 * Added and corrected references: CORS, RFC3912, RFC3987, 586 RFC5890. 588 * Expanded on first use several acronyms. 590 * Updated 2119 language. 592 -05 594 * Update the media type registration. 596 * Further explained the SHOULD in section 5. 598 * Split the references into normative and informative. 600 * Other minor fixes. 602 -06 604 * Rewritten the third paragraph in Section 3 to avoid 605 contradictions 607 * Simplified the wording in Seciton 5.1. 609 * Removed some RFC 2119 words in Section 5.2, 5.3, 5.4 and 5.5. 611 * Corrected RFC 6839 as an informative reference. 613 * Replaced MAYs with cans in Seciton 9.1. 615 * Replaced MAY with can in Appendix B. 617 * Added a note in in Appendix C for the RFC Editor to remove this 618 section. 620 -07 622 * Dropped reference to MUST with application/rdap+json 624 * Dropped IANA registration of application/rdap+json 626 -08 628 * Keep alive version. 630 -09 632 * Changed status lines in example to include http version number. 634 * Removed charset from media types in examples. 636 * Changed wording of 404 negative response to specifically say 637 "empty result set". 639 * Changed references to HTTP. 641 Authors' Addresses 643 Andrew Lee Newton 644 American Registry for Internet Numbers 645 3635 Concorde Parkway 646 Chantilly, VA 20151 647 US 649 Email: andy@arin.net 650 URI: http://www.arin.net 652 Byron J. Ellacott 653 Asia Pacific Network Information Center 654 6 Cordelia Street 655 South Brisbane QLD 4101 656 Australia 658 Email: bje@apnic.net 659 URI: http://www.apnic.net 660 Ning Kong 661 China Internet Network Information Center 662 4 South 4th Street, Zhongguancun, Haidian District 663 Beijing 100190 664 China 666 Phone: +86 10 5881 3147 667 Email: nkong@cnnic.cn