Content-type header field for Internet messages
RFC 1049
Document | Type | RFC - Historic (March 1988) | |
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Authors | |||
Last updated | 2013-03-02 | ||
RFC stream | Legacy stream | ||
Formats | |||
IESG | Responsible AD | (None) | |
Send notices to | (None) |
RFC 1049
RFC 1049 Mail Content Type March 1988 the Standard Generalized Markup Language, IS 8879, as published by the International Organization for Standardization. [3] Documents structured according to the ISO DIS 8613--Office Docment Architecture and Interchange Format--may also be encoded using SGML syntax. TEX Indicates the document contains embedded formatting information according to the syntax of the TEX document production language. [4] TROFF Indicates the document contains embedded formatting information according to the syntax specified for the TROFF formatting package developed by AT&T Bell Laboratories. [5] DVI Indicates the document contains information according to the device independent file format produced by TROFF or TEX. "X-"atom Any type value beginning with the characters "X-" is a private value. 3.2. Version Number Since standard structuring techniques in fact evolve over time, we leave room for specifying a version number for the content type. Valid values will depend upon the type parameter. ver-num:= local-part In particular, we have the following valid values: For type=POSTSCRIPT ver-num:= "1.0"/"2.0"/"null" For type=SCRIBE ver-num:= "3"/"4"/"5"/"null" For type=SGML ver-num:="IS.8879.1986"/"null" 3.3. Resource Reference resource-ref:= local-part Sirbu [Page 6] RFC 1049 Mail Content Type March 1988 As Apple has demonstrated with their implementation of the Laserwriter, a very general document structuring technique can be made more efficient by defining a set of macros or other similar resources to be used in interpreting any transmitted stream. The Macintosh transmits a LaserPrep file to the Laserwriter containing font and macro definitions which can be called upon by subsequent documents. The result is that documents as sent to the Laserwriter are considerably more compact than if they had to include the LaserPrep file each time. The Resource Reference parameter allows specification of a well known resource, such as a LaserPrep file, which should be used by the receiving system when processing the message. Resource references could also include macro packages for use with TEX or references to preprocessors such as eqn and tbl for use with troff. Allowed values will vary according to the type parameter. In particular, we propose the following values: For type = POSTSCRIPT resource-ref:= "laserprep2.9"/"laserprep3.0"/"laserprep3.1"/ "laserprep4.0"/local-part For type = TROFF resource-ref:= "eqn"/"tbl"/"me"/local-part 3.4. Comment The comment field can be any additional comment text the user desires. Comments are enclosed in parentheses as specified in RFC-822. 4. Conclusion A standardized Content-type field allows mail reading systems to automatically identify the type of a structured message body and to process it for display accordingly. The strcutured message body must still conform to the RFC-822 requirements concerning allowable characters. A mail reading system need not take any specific action upon receiving a message with valid Content-Type header field. The ability to recognize this field and invoke the appropriate display process accordingly will, however, improve the readability of messages, and allow the exchange of messages containing mathematical symbols, or foreign language characters. Sirbu [Page 7] RFC 1049 Mail Content Type March 1988 In the near term, the major use of a Content-Type: header field is likely to be for designating the message body as containing a Page Definition Language representation such as Postscript. Additional type values shall be registered with Internet Assigned Numbers Coordinator at USC-ISI. Please contact: Joyce K. Reynolds USC Information Sciences Institute 4676 Admiralty Way Marina del Rey, CA 90292-6695 213-822-1511 JKReynolds@ISI.EDU REFERENCES 1. Adobe Systems, Inc. Postscript Language Reference Manual. Addison-Wesley, Reading, Mass., 1985. 2. Crocker, David H. RFC-822: Standard for the Format of ARPA Internet Text Messages. Network Information Center, August 13, 1982. 3. ISO TC97/SC18. Standard Generalized Markup Language. Tech. Rept. DIS 8879, ISO, 1986. 4. Knuth, Donald E. The TEXbook. Addison-Wesley, Reading, Mass., 1984. 5. Ossanna, Joseph F. NROFF/TROFF User's Manual. Bell Laboratories, Murray Hill, New Jersey, 1976. Computing Science Technical Report No.54. 6. Unilogic. SCRIBE Document Production Software. Unilogic, 1985. Fourth Edition. Sirbu [Page 8]