MIME Type IANA Registration

D.3 MIME Type IANA Registration

The MIME media type registration process is described in RFC 2048. The goal of the registration process is to make it easy to register new media types but also to provide some sanity checking to make sure the new types are well thought out.

D.3.1 Registration Trees

MIME type tokens are split into four classes, called "registration trees," each with its own registration rules. The four treesIETF, vendor, personal, and experimentalare described in Table D-2 .

Table D-2. Four MIME media type registration trees

Registration tree

Example

Description

IETF

text/html

(HTML text)

The IETF tree is intended for types that are of general significance to the Internet community. New IETF tree media types require approval by the Internet Engineering Steering Group (IESG) and an accompanying standards-track RFC.

IETF tree types have no periods (.) in tokens.

Vendor

(vnd.)

image/vnd.fpx

(Kodak FlashPix image)

The vendor tree is intended for media types used by commercially available products. Public review of new vendor types is encouraged but not required.

Vendor tree types begin with "vnd.".

Personal/Vanity

(prs.)

image/prs.btif

(internal check-management format used by Nations Bank)

Private, personal, or vanity media types can be registered in the personal tree. These media types will not be distributed commercially.

Personal tree types begin with "prs.".

Experimental

(x- or x.)

application/x-tar

(Unix tar archive)

The experimental tree is for unregistered or experimental media types. Because it's relatively simple to register a new vendor or personal media type, software should not be distributed widely using x- types.

Experimental tree types begin with "x." or "x-".

D.3.2 Registration Process

Read RFC 2048 carefully for the details of MIME media type registration.

The basic registration process is not a formal standards process; it's just an administrative procedure intended to sanity check new types with the community, and record them in a registry, without much delay. The process follows the following steps:

1.             Present the media type to the community for review.

Send a proposed media type registration to the ietf-types@iana.org mailing list for a two-week review period. The public posting solicits feedback about the choice of name , interoperability, and security implications. The "x-" prefix specified in RFC 2045 can be used until registration is complete.

2.             IESG approval (for IETF tree only).

If the media type is being registered in the IETF tree, it must be submitted to the IESG for approval and must have an accompanying standards-track RFC.

3.             IANA registration.

As soon as the media type meets the approval requirements, the author can submit the registration request to the IANA, using the email template in Example D-1 and mailing the information to ietf-types@iana.org. The IANA will register the media type and make the media type application available to the community at http://www.isi.edu/in-notes/iana/assignments/media-types/ .

D.3.3 Registration Rules

The IANA will register media types in the IETF tree only in response to a communication from the IESG stating that a given registration has been approved.

Vendor and personal types will be registered by the IANA automatically and without any formal review as long as the following minimal conditions are met:

1.             Media types must function as actual media formats. Types that act like transfer encodings or character sets may not be registered as media types.

2.             All media types must have proper type and subtype names. All type names must be defined by standards-track RFCs. All subtype names must be unique, must conform to the MIME grammar for such names , and must contain the proper tree prefixes.

3.             Personal tree types must provide a format specification or a pointer to one.

4.             Any security considerations given must not be obviously bogus . Everyone who is developing Internet software needs to do his part to prevent security holes.

D.3.4 Registration Template

The actual IANA registration is done via email. You complete a registration form using the template shown in Example D-1 , and mail it to ietf-types@iana.org . [1]

[1] The lightly structured nature of the form makes the submitted information fine for human consumption but difficult for machine processing. This is one reason why it is difficult to find a readable, well-organized summary of MIME types, and the reason we created the tables that end this appendix.

Example D-1. IANA MIME registration email template
 To: ietf-types@iana.org 
 Subject: Registration of MIME media type XXX/YYY 
 
 MIME media type name: 
 
 MIME subtype name: 
 
 Required parameters: 
 
 Optional parameters: 
 
 Encoding considerations: 
 
 Security considerations: 
 
  Interoperability considerations:  
   
  Published specification:  
   
  Applications which use this media type:  
   
  Additional information:  
   
  Magic number(s):  
  File extension(s):  
  Macintosh File Type Code(s):  
   
  Person & email address to contact for further information:  
   
  Intended usage:  
   
  (One of COMMON, LIMITED USE or OBSOLETE)  
   
  Author/Change controller:  
   
  (Any other information that the author deems interesting may be added below this line.)  

D.3.5 MIME Media Type Registry

The submitted forms are accessible from the IANA web site ( http://www.iana.org ). At the time of writing, the actual database of MIME media types is stored on an ISI web server, at http://www.isi.edu/in-notes/iana/assignments/media-types/ .

The media types are stored in a directory tree, structured by primary type and subtype, with one leaf file per media type. Each file contains the email submission. Unfortunately, each person completes the registration template slightly differently, so the quality and format of information varies across submissions. (In the tables in this appendix, we tried to fill in the holes omitted by registrants.)

 



HTTP. The Definitive Guide
HTTP: The Definitive Guide
ISBN: 1565925092
EAN: 2147483647
Year: 2001
Pages: 294

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net