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This document defines MIME types "text/csv" and "text/comma-separated-values" which used for Comma-Separated Values (CSV) files.
2. MIME Type Registration of text/csv and text/comma-separated-values
3. IANA Considerations
4. Security Considerations
5.1 Normative References
5.2 Informative References
§ Author's Address
A. Appendix A - Discussion of the CSV format
§ Intellectual Property and Copyright Statements
The comma separated values format (CSV) has been used for exchanging and converting data between various spreadsheet programs for quite some time. Surprisingly, while this file is very common it has never been formally documented. Additionally, while the IANA MIME registration tree includes a registraton for "text/tab-separated-values" type, no MIME types have ever been registered with IANA for CSV. At the same time, various programs and operating systems have begun to use different MIME types for this format, many of which vary from system to system. This document seeks to formally register two MIME types for CSV in accordance with RFC 2048Freed, N., Klensin, J. and J. Postel, Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures, November 1996..
This section provides the media-type registration application (as per RFC 2048Freed, N., Klensin, J. and J. Postel, Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures, November 1996., which will be submitted to IANA after IESG approval of this document.
Subject: Registration of MIME media types text/csv and text/comma-separated-values
MIME media type name: text
MIME subtype name: csv, comma-separated-values
Required parameters: none
Optional parameters: charset
Common usage of CSV is US-ASCII, but other character sets as defined by IANA for the "text" tree may be used.
While section 4.1.1. of RFC 2046Freed, N. and N. Borenstein, Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types, November 1996. stipulates that "text" subtypes MUST use a CRLF sequence as a line break, in practice that is not always true for CSV. Therefore, implementors should be aware that either CR or CRLF maybe used as a line break for this format.
CSV files contain passive text data which should not pose any risks. However, it is possible in theory that malicious binary data maybe included in order to exploit potential buffer overruns in the program processing CSV data. Additionally, private data maybe shared via this format which of course applies to any text data.
Due to lack of a single specification there are considerable differences among different implementations as described in appendix A. The most common difference among various format is whether double quotes (") are used to enclose strings. Implementors should "be conservative in what you do, be liberal in what you accept from others" (RFC 793Postel, J., Transmission Control Protocol, September 1981.) when processing CSV files.
While numerous private specifications exist for various programs and systems, there is no single "master" specification for this format. A sampling of formats and discussion of differences is included in appendix A.
Applications which use this media type:
Spreadsheet programs and various data conversion utilities
Magic number(s): none
File extension(s): CSV
Macintosh File Type Code(s): TEXT
Person & email address to contact for further information:
Yakov Shafranovich <email@example.com>
Intended usage: COMMON
Author/Change controller: IESG
After IESG approval, IANA is expected to register these two types "text/csv" and "text/comma-separated-values" using the application provided in this document.
See discussion above
|||Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996.|
|||Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981.|
|||Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997 (TXT, HTML, XML).|
|||Freed, N., Klensin, J. and J. Postel, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", BCP 13, RFC 2048, November 1996 (TXT, HTML, XML).|
|||Repici, J., "HOW-TO: The Comma Separated Value (CSV) File Format", 2004 (HTML).|
|||Edoceo, Inc., "CSV Standard File Format", 2004 (HTML).|
|||Rodger, R. and O. Shanaghy, "Documentation for Ricebridge CSV Manager", February 2005 (HTML).|
|||Raymond, E., "The Art of Unix Programming, Chapter 5", September 2003 (HTML).|
|SolidMatrix Technologies, Inc.|
While there are various specifications and implementations for the CSV format (for ex. Repici, J., HOW-TO: The Comma Separated Value (CSV) File Format, 2004., Edoceo, Inc., CSV Standard File Format, 2004., Rodger, R. and O. Shanaghy, Documentation for Ricebridge CSV Manager, February 2005. and Raymond, E., The Art of Unix Programming, Chapter 5, September 2003.), no formal specification exists. This causes a wide variety of interpretations for CSV files. While this document does not seek to document the CSV format, nevertheless we want to document the format that seems to be followed by most implementations:
The ABNF grammarCrocker, D., Ed. and P. Overell, Augmented BNF for Syntax Specifications: ABNF, November 1997. appears as follows:
COMMA = %x2C
file = [header] *record
end-of-field = COMMA / (CR / CRLF)
header = *(*WSP field *WSP end-of-field)
record = *(*WSP field *WSP end-of-field)
field = escaped / non-escaped
escaped = DQUOTE *(VCHAR / CR / CRLF / 3*DQUOTE) DQUOTE
non-escaped = *VCHAR
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