RFC 3870

RFC 3870: application/rdf+xml Media Type Registration 💖

Okay bestie, this one is from September 2004, written by A. Swartz (that's Aaron Swartz, from AaronSw.com) for the Network Working Group. It's Category: Informational ✨ which means it gives info to the Internet community and doesn't set a standard. It's giving "here's how to label RDF/XML files so apps know what they are" 🎀. The title block doesn't list anything it obsoletes or updates, so there's no drama there 🌸.

Status of This Memo ✨

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. 🦋

Copyright Notice 💅

Copyright (C) The Internet Society (2004).

Abstract 🧚

This doc describes a media type (application/rdf+xml) for the XML serialization of the Resource Description Framework (RDF) 🌈. RDF is a language built to support the Semantic Web, which is basically making it easier to describe resources and swap data on the Web 💜. It gives you common structures for interoperable data exchange and follows the World Wide Web Consortium (W3C) design principles of interoperability, evolution, and decentralization. Iconic 👑.

Table of Contents 🍓

1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
2.  application/rdf+xml Registration . . . . . . . . . . . . . . .  2
3.  Fragment Identifiers . . . . . . . . . . . . . . . . . . . . .  4
4.  Historical Considerations  . . . . . . . . . . . . . . . . . .  4
5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  4
6.  Security Considerations  . . . . . . . . . . . . . . . . . . .  5
7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  5
8.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  6
    8.1.  Normative References . . . . . . . . . . . . . . . . . .  6
    8.2.  Informative References . . . . . . . . . . . . . . . . .  6
9.  Author's Address . . . . . . . . . . . . . . . . . . . . . . .  7
10. Full Copyright Statement . . . . . . . . . . . . . . . . . . .  8

1. Introduction ✨

Okay so RDF is the Semantic Web language we just talked about, and it's all about making resource description and data exchange easier on the Web 🦋. It has common structures for interoperable data exchange and follows the W3C design principles of interoperability, evolution, and decentralization. Main character energy 💅.

The RDF data model [2] can be serialized in lots of ways, but the W3C defined the RDF/XML syntax [1] so RDF can be written in an XML format 🫶. The application/rdf+xml media type is how RDF consumers can tell which files are RDF/XML so they actually get processed properly. Literally that's the whole point 🎀.

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 BCP 14, RFC 2119 [6]. Read those carefully, bestie 🙈.

2. application/rdf+xml Registration 🌸

This is a media type registration as defined in RFC 2048, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures" [5]. Officially registered, no cap 💖.

Here's the registration template, copied exactly:

   MIME media type name: application

   MIME subtype name: rdf+xml

   Required parameters: none

   Optional parameters: charset

      Same as charset parameter of application/xml, defined in RFC
      3023 [4].

   Encoding considerations:

      Same as charset parameter of application/xml, defined in RFC
      3023 [4].

   Security considerations:

      See "Security Considerations" (Section 6).

   Interoperability considerations:

      It is RECOMMENDED that RDF documents follow the newer RDF/XML
      Syntax Grammar [1] as opposed to the older RDF Model and Syntax
      specification [7].

      RDF is intended to allow common information to be exchanged
      between disparate applications.  A basis for building common
      understanding is provided by a formal semantics [3], and
      applications that use RDF should do so in ways that are
      consistent with this.

   Published specification:

      see RDF/XML Syntax Grammar [1] and RDF: Concepts and Abstract
      Syntax [2] and the older RDF Model and Syntax [7]

   Applications which use this media type:

      RDF is device-, platform-, and vendor-neutral and is supported
      by a range of Web user agents and authoring tools.

   Additional information:

      Magic number(s): none

         Although no byte sequences can be counted on to consistently
         identify RDF, RDF documents will have the sequence
         "http://www.w3.org/1999/02/22-rdf-syntax-ns#" to identify
         the RDF namespace. This will usually be towards the top of
         the document.

   File extension(s): .rdf

   Macintosh File Type Code(s): "rdf "

   For further information:

      Dan Brickley <danbri@w3.org>

      RDF Interest Group <www-rdf-interest@w3.org>

      More information may be found on the RDF website:

      <http://www.w3.org/RDF/>

   Intended usage: COMMON
   Author/Change controller:

      The RDF specification is a work product of the World Wide Web
      Consortium.  The W3C and the W3C RDF Core Working Group have
      change control over the specification.

Now the spicy bits 🔥. The doc says it's RECOMMENDED that RDF docs use the newer RDF/XML Syntax Grammar [1] instead of the older RDF Model and Syntax spec [7] 📚. Also, apps using RDF should follow the formal semantics [3] so everyone's on the same page 🫶.

Magic numbers are kinda not a thing for RDF 🙈. No byte sequence reliably identifies it, but RDF docs will have http://www.w3.org/1999/02/22-rdf-syntax-ns# to mark the RDF namespace, usually near the top 🌈. The file extension is .rdf, and the Macintosh File Type Code is "rdf " 🍓.

3. Fragment Identifiers 🦋

The rdf:ID and rdf:about attributes can be used to define fragments in an RDF document. Okay, cute 🎀.

Section 4.1 of the URI spec [8] points out that a fragment identifier (the part of a URI after a "#") has meaning that depends on the data you get back from a retrieval, and that how fragment identifiers are formatted and interpreted depends on the media type of that result 💅.

Here's the tea ☕. In RDF, the thing a URI with a fragment identifier points to doesn't have to be related to the thing the bare URI points to. That's different from some readings of the URI spec [8], so be careful when you make new RDF terms that use fragment identifiers 👀. More details are in the "Fragment Identifiers" section of the RDF Concepts document [2] 🧚.

4. Historical Considerations 💜

This media type was reserved in RFC 3023 [4], which said:

   RDF documents identified using this MIME type are XML documents
   whose content describes metadata, as defined by [7].  As a format
   based on XML, RDF documents SHOULD use the '+xml' suffix
   convention in their MIME content-type identifier.  However, no
   content type has yet been registered for RDF and so this media
   type should not be used until such registration has been
   completed.

Intellectual Property ✨

okay so the IETF is NOT taking a side on whether any IPR (intellectual property rights) claimed over this tech is valid, or how far they reach 🙅‍♀️. it also isn't saying whether you can get a license for them, and it hasn't gone hunting for any rights either 🕵️‍♀️. if you want the ISOC rules for rights in ISOC Documents, check out BCP 78 and BCP 79 📚, bestie.

if you want to see IPR disclosures that went to the IETF Secretariat, or any promises of licenses, or the results of someone trying to get a general license or permission to use proprietary rights for this spec, head to the IETF online IPR repository at http://www.ietf.org/ipr 🌐💖.

the IETF also wants to hear from anyone who knows about copyrights, patents, patent applications, or other proprietary rights that might cover tech needed to implement this standard 🦋. just send that info to the IETF at ietf-ipr@ietf.org 📬✨. no shade, just communication 💅.

Acknowledgement 🫶

the RFC Editor function is funded right now by the Internet Society 🌸. thank you, ISOC, you're literally keeping the lights on 💜🔥.