Network Working Group A.L. Newton
Internet-Draft ARIN
Intended status: Standards Track B.J. Ellacott
Expires: September 28, 2013 APNIC
N. Kong
CNNIC
March 27, 2013
Using the Registration Data Access Protocol (RDAP) with HTTP
draft-ietf-weirds-using-http-03
Abstract
This document describes the usage of the Registration Data Access
Protocol (RDAP) using HTTP.
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Newton, et al. Expires September 28, 2013 [Page 1]
Internet-Draft RDAP over HTTP March 2013 1. Introduction This document describes the usage of HTTP for Registration Data Directory Services running on RESTful web servers. The goal of this document is to tie together the usage patterns of HTTP into a common profile applicable to the various types of Directory Services serving Registration Data using RESTful styling. By giving the various Directory Services common behavior, a single client is better able to retrieve data from Directory Services adhering to this behavior. In designing these common usage patterns, this draft endeavours to satisfy requirements for a Registration Data Access Protocol (RDAP). This draft also introduces an additional design consideration to define a simple use of HTTP. Where complexity may reside, it is the goal of this specification to place it upon the server and to keep the client as simple as possible. A client implementation should be possible using common operating system scripting tools. This is the basic usage pattern for this protocol: 1. A client issues an HTTP query using GET. As an example, a query for the network registration 192.0.2.0 might be http:// example.com/ip/192.0.2.0. 2. If the receiving server has the information for the query, it examines the Accept header field of the query and returns a 200 response with a response entity appropriate for the requested format. 3. If the receiving server does not have the information for the query but does have knowledge of where the information can be found, it will return a redirection response (3xx) with the Location: header containing an HTTP URL pointing to the information or another server known to have knowledge of the location of the information. The client is expected to re-query using that HTTP URL. 4. If the receiving server does not have the information being requested and does not have knowledge of where the information can be found, it should return a 404 response. It is important to note that it is not the intent of this document to redefine the meaning and semantics of HTTP. The purpose of this document is to clarify the use of standard HTTP mechanisms for this application. 2. Terminology Newton, et al. Expires September 28, 2013 [Page 2]
Internet-Draft RDAP over HTTP March 2013 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 RFC 2119 [RFC2119]. As is noted in SSAC Report on WHOIS Terminology and Structure [SAC-051], the term "Whois" is overloaded, often referring to a protocol, a service and data. In accordance with [SAC-051], this document describes the base behavior for a Registration Data Access Protocol (RDAP). [SAC-051] describes a protocol profile of RDAP for Domain Name Registries (DNRs), DNRD-AP. This document and others from the IETF WEIRDS working group describe a single protocol, RDAP, for access to the data of both DNRs and Regional Internet Registries (RIRs). RIRs are also often referred to as number resource registries and are responsible for the registration of IP address networks and autonomous system numbers. 3. Design Intents There are a few design criteria this document attempts to support. First, each query is meant to return either zero or one result. With the maximum upper bound being set to one, the issuance of redirects is simplified to the known query/response model used by HTTP [RFC2616]. Should a result contain more than one result, some of which are better served by other servers, the redirection model becomes much more complicated. Second, multiple response formats are supported by this protocol. At present the IETF WEIRDS working group is defining only a JSON [RFC4627] response format, but server operators may use other data formats when those formats are requested. Third, HTTP offers a number of transport protocol mechanisms not described further in this document. Operators are able to make use of these mechanisms according to their local policy, including cache control, authorization, compression, and redirection. HTTP also benefits from widespread investment in scalability, reliability, and performance, and widespread programmer understanding of client behaviours for RESTful web services, reducing the cost to deploy Registration Data Directory Services and clients. 4. Queries Newton, et al. Expires September 28, 2013 [Page 3]
Internet-Draft RDAP over HTTP March 2013 4.1. Accept Header RDAP clients MUST include an Accept: header specifying application/ rdap+json, application/json, or both. Servers receiving an RDAP request MUST return an entity with Content-Type application/ rdap+json. This specification does not define the responses a server returns to a request with any other media types in the Accept: header, or with no Accept: header. One possibility would be to return a response in a media type suitable for rendering in a web browser. 4.2. Query Parameters Servers SHOULD ignore unknown query parameters. Use of unknown query parameters for cache-busting is described in Appendix A. 5. Types of HTTP Response This section describes the various types of responses a server may send to a client. While no standard HTTP response code is forbidden in usage, at a minimum clients SHOULD understand the response codes described in this section. It is expected that usage of response codes and types for this application not defined here will be described in subsequent documents. 5.1. Positive Answers If a server has the information requested by the client and wishes to respond to the client with the information according to its policies, it SHOULD encode the answer in the format most appropriate according to the standard and defined rules for processing the HTTP Accept header, and return that answer in the body of a 200 response. 5.2. Redirects If a server wishes to inform a client that the answer to a given query can be found elsewhere, it SHOULD return either a 301 or a 307 response code and an HTTP URL in the Location: header. The client is expected to issue a subsequent query using the given URL without any processing of the URL. In other words, the server is to hand back a complete URL and the client should not have to transform the URL to follow it. A server SHOULD use a 301 response to inform the client of a permanent move and a 307 response otherwise. For this application, such an example of a permanent move might be a top level domain (TLD) operator informing a client the information being sought can be found Newton, et al. Expires September 28, 2013 [Page 4]
Internet-Draft RDAP over HTTP March 2013 with another TLD operator (i.e. a query for the domain bar in foo.example is found at http://foo.example/domain/bar). In other words, when generating the redirect url, the server will only alter the base of the URL. It will not attempt to normalize or modify the path segment. For example, if the client sends http://serv1.example.com/weirds/ domain/example.com, the server redirecting to https:// serv2.example.net/weirds2/ would set the Location: field to the value: https://serv2.example.net/weirds2/domain/example.com. 5.3. Negative Answers If a server wishes to respond that it has no information regarding the query, it SHOULD return a 404 response code. Optionally, it MAY include additional information regarding the negative answer in the HTTP entity body. 5.4. Malformed Queries If a server receives a query which it cannot understand, it SHOULD return a 400 response code. Optionally, it MAY include additional information regarding this negative answer in the HTTP entity body. 5.5. Rate Limits Some servers apply rate limits to deter address scraping and other abuses. When a server declines to answer a query due to rate limits, it MAY return a 429 response code as described in [RFC6585]. A client that receives a 429 response SHOULD decrease its query rate, and honor the Retry-After header if one is present. Note that this is not a defense against denial-of-service attacks, since a malicious client could ignore the code and continue to send queries at a high rate. 5.6. Cross-Origin Resource Sharing When responding to queries, it is RECOMMENDED that servers use the Access-Control-Allow-Origin header, as specified by [W3C.WD-cors-20130129]. Newton, et al. Expires September 28, 2013 [Page 5]
Internet-Draft RDAP over HTTP March 2013 6. Extensibility For extensibility purposes, this document defines an IANA registry for prefixes used in JSON [RFC4627] data serialization and URI path segments (see Section 7). Prefixes and identifiers SHOULD only consist of the alphabetic ASCII characters A through Z in both uppercase and lowercase, the numerical digits 0 through 9, underscore characters, and SHOULD NOT begin with an underscore character, numerical digit or the characters "xml". The following describes the production of JSON names in ABNF [RFC5234]. ABNF for JSON names name = ALPHA *( ALPHA / DIGIT / "_" ) Figure 1 This restriction is a union of the Ruby programming language identifier syntax and the XML element name syntax and has two purposes. First, client implementers using modern programming languages such as Ruby or Java may use libraries that automatically promote JSON names to first order object attributes or members. Second, a clean mapping between JSON and XML is easy to accomplish using these rules. 7. IANA Considerations 7.1. RDAP Extensions Registry This specification proposes an IANA registry for RDAP extensions. The purpose of this registry is to ensure uniqueness of extension identifiers. The extension identifier is used as prefix in JSON names and as a prefix of path segments in RDAP URLs. The production rule for these identifiers is specified in Section 6. In accordance with RFC5226, the IANA policy for assigning new values shall be Specification Required: values and their meanings must be documented in an RFC or in some other permanent and readily available reference, in sufficient detail that interoperability between independent implementations is possible. The following is a preliminary template for an RDAP extension registration: Newton, et al. Expires September 28, 2013 [Page 6]
Internet-Draft RDAP over HTTP March 2013 Extension identifier: the identifier of the extension Registry operator: the name of the registry operator Published specification: RFC number, bibliographical reference or URL to a permanent and readily available specification Person & email address to contact for further information: The names and email addresses of individuals for contact regarding this registry entry Intended usage: brief reasons for this registry entry The following is an example of a registration in the RDAP extension registry: Extension identifier: lunarNic Registry operator: The Registry of the Moon, LLC Published specification: http://www.example/moon_apis/rdap Person & email address to contact for further information: Professor Bernardo de la Paz <berny@moon.example> Intended usage: COMMON 7.2. RDAP Media Type Registration This specification registers the "application/rdap+json" media type. Type name: application Subtype name: rdap+json Required parameters: n/a Encoding considerations: n/a Security considerations: n/a Interoperability considerations: n/a Published specification: [[ this document ]] Applications that use this media type: RDAP Additional information: n/a Newton, et al. Expires September 28, 2013 [Page 7]
Internet-Draft RDAP over HTTP March 2013 Person & email address to contact for further information: Andy Newton &andy@hxr.us& Intended usage: COMMON Restrictions on usage: none Author: Andy Newton Change controller: IETF Provisional Registration: Yes 8. Internationalization Considerations 8.1. URIs and IRIs Clients MAY use IRIs as they see fit, but MUST transform them to URIs [RFC3986] for interaction with RDAP servers. RDAP servers MUST use URIs in all responses, and clients MAY transform these URIs to IRIs. 8.2. Language Identifiers in Queries and Responses Depending on the data format of the response, servers MAY include data in character sets other than ASCII and languages other than English (the data format will most likely be in Unicode and almost certainly languages other than English will be encountered). Under most scenarios, clients requesting data will not signal that the data be returned in a particular language or script. On the other hand, when servers return data and have knowledge that the data is in a language or script, the data should be annotated with language identifiers thus allowing clients to process and display the data accordingly. 8.3. Language Identifiers in HTTP Headers Given the description of the use of language identifiers in Section 8.2, unless otherwise specified servers SHOULD ignore the HTTP [RFC2616] Accept-Language header when formulating responses. However, servers MAY return language identifiers in the Content- Language header so as to inform clients of the intended language of HTTP layer messages. 9. Contributing Authors and Acknowledgements John Levine provided text to tighten up the Accept header usage and the text for the section on 429 responses. Newton, et al. Expires September 28, 2013 [Page 8]
Internet-Draft RDAP over HTTP March 2013 Marc Blanchet provided some clarifying text regarding the use of URLs with redirects. 10. Normative References [SAC-051] Piscitello, D., Ed., "SSAC Report on Domain Name WHOIS Terminology and Structure", September 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4627] Crockford, D., "The application/json Media Type for JavaScript Object Notation (JSON)", RFC 4627, July 2006. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status Codes", RFC 6585, April 2012. [W3C.WD-cors-20130129] Kesteren, A., "Cross-Origin Resource Sharing", World Wide Web Consortium LastCall WD-cors-20130129, January 2013, <http://www.w3.org/TR/2012/WD-cors-20130129>. Appendix A. Cache Busting To overcome issues with misbehaving HTTP [RFC2616] cache infrastructure, clients MAY use an adhoc and improbably used query parameter with a random value of their choosing. As Section 4.2 instructs servers to ignore unknown parameters, this is unlikely to have any known side effects. An example of using an unknown query parameter to bust caches: http://example.com/ip/192.0.2.0?__fuhgetaboutit=xyz123 Newton, et al. Expires September 28, 2013 [Page 9]
Internet-Draft RDAP over HTTP March 2013 Use of an unknown parameter to overcome misbehaving caches is not part of any specification and is offered here for informational purposes. Appendix B. Changelog Initial WG -00: Updated to working group document 2012-September-20 -01 * Updated for the sections moved to the JSON responses draft. * Simplified media type, removed "level" parameter. * Updated 2119 language and added boilerplate. * In section 1, noted that redirects can go to redirect servers as well. * Added Section 8.2 and Section 8.3. -02 * Added a section on 429 response codes. * Changed Accept header language in section 4.1 * Removed reference to the now dead requirements draft. * Added contributing authors and acknowledgements section. * Added some clarifying text regarding complete URLs in the redirect section. * Changed media type to application/rdap+json * Added media type registration -03 * Removed forward reference to draft-ietf-weirds-json-response. * Added reference and recommended usage of CORS Authors' Addresses Newton, et al. Expires September 28, 2013 [Page 10]
Internet-Draft RDAP over HTTP March 2013 Andrew Lee Newton American Registry for Internet Numbers 3635 Concorde Parkway Chantilly, VA 20151 US Email: andy@arin.net URI: http://www.arin.net Byron J. Ellacott Asia Pacific Network Information Center 6 Cordelia Street South Brisbane QLD 4101 Australia Email: bje@apnic.net URI: http://www.apnic.net Ning Kong China Internet Network Information Center 4 South 4th Street, Zhongguancun, Haidian District Beijing 100190 China Phone: +86 10 5881 3147 Email: nkong@cnnic.cn Newton, et al. Expires September 28, 2013 [Page 11]
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draft-ietf-weirds-using-http-03
This is an older version of an Internet-Draft that was ultimately published as RFC 7480.
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