|Network Working Group||J. Reschke|
|Updates: 2616 (if approved)||August 24, 2010|
|Intended status: Standards Track|
|Expires: February 25, 2011|
Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP)
HTTP/1.1 defines the Content-Disposition response header field, but points out that it is not part of the HTTP/1.1 Standard. This specification takes over the definition and registration of Content-Disposition, as used in HTTP, and clarifies internationalization I ↓
This specification is expected to replace the definition of Content-Disposition in the HTTP/1.1 specification, as currently revised by the IETF HTTPbis working group. See also <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/123>.
Distribution of this document is unlimited. Although this is not a work item of the HTTPbis Working Group, comments should be sent to the Hypertext Transfer Protocol (HTTP) mailing list at firstname.lastname@example.org, which may be joined by sending a message with subject "subscribe" to email@example.com.
Discussions of the HTTPbis Working Group are archived at <http://lists.w3.org/Archives/Public/ietf-http-wg/>.
XML versions, latest edits and the issues list for this document are available from <http://greenbytes.de/tech/webdav/#draft-reschke-rfc2183-in-http>. A collection of test cases is available at <http://greenbytes.de/tech/tc2231/>.
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|I edit (type: edit, status: open)|
|firstname.lastname@example.org||2009-10-16||Umbrella issue for editorial fixes/enhancements.|
|Associated changes in this document: <#rfc.change.edit.1>, 1, 3, 3, 3.1, 3.1, 3.2, 3.2, 3.2, 3.2, 3.2, 3.3, 3.4, 4, <#rfc.change.edit.15>, 6, 8, 9.1, 9.2, 9.2, 9.2, A, B, <#rfc.change.edit.24>, D.|
|I nodep2183 (type: change, status: closed)|
|email@example.com||2010-08-23||Make sure we do not have a normative dependency on RFC 2183.|
|Associated changes in this document: 1, 3.2, 3.4, 9.1, 9.2.|
HTTP/1.1 defines the Content-Disposition response header field in Section 19.5.1 of [RFC2616], but points out that it is not part of the HTTP/1.1 Standard (Section 15.5):
Content-Disposition is not part of the HTTP standard, but since it is widely implemented, we are documenting its use and risks for implementors.
This specification takes over the definition and registration of Content-Disposition, as used in HTTP. Based on interoperability testing with existing User Agents, it I ↓defines a profile of the features defined in the MIME variant ([RFC2183]) of the header field, and also clarifies internationalization ↑ I ↓
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 [RFC2119].
This specification uses the augmented BNF notation defined in Section 2.1 of [RFC2616], including its rules for linear whitespace (LWS).
content-disposition = "Content-Disposition" ":" disposition-type *( ";" disposition-parm ) disposition-type = "inline" | "attachment" | disp-ext-type ; case-insensitive disp-ext-type = token disposition-parm = filename-parm | disp-ext-parm filename-parm = "filename" "=" value | "filename*" "=" ext-value disp-ext-parm = token "=" value | ext-token "=" ext-value ext-token = <the characters in token, followed by "*">
|I quoted (type: change, status: open)|
|firstname.lastname@example.org||2010-08-23||Can value be quoted-pair as well? It is "value" only in RFC 2183, but "quoted-string" only in 2616. UAs seem to handle quoted-strings, although some have trouble unescaping backslashes.|
Defined in [RFC2616]:
token = <token, defined in [RFC2616], Section 2.2> value = <value, defined in [RFC2616], Section 3.6>
Defined in ↑ I ↓
ext-value = <ext-value, defined in ↑ I ↓
[draft-reschke-rfc2231-in-http], Section 3.2>
If the disposition type matches "attachment" (case-insensitively), ↑ I ↓
the implied suggestion is that the user agent should not display the response, but directly enter a "save ↑ I ↓ response as..." dialog.
On the other hand, if it matches "inline"↑ I ↓, this implies ↑ I ↓
regular processing. ↑ I ↓ Note that this type may be used when it is desirable to transport filename information for the case of a subsequent, user-initiated, save operation.
Other disposition types SHOULD be handled the same way as "attachment" (↑ I ↓[RFC2183], Section 2.8).
[rfc.comment.1: Talk about expected behavior, mention security considerations.]
↑ I ↓
Parameters other than "filename" SHOULD be ignored (↑ I ↓[RFC2183], Section 2.8).
Direct UA to show "save as" dialog, with a filename of "foo.html":
Content-Disposition: Attachment; filename=foo.html
Direct UA to behave as if the Content-Disposition header field wasn't present, but to remember the filename "foo.html" for a subsequent save operation:
Content-Disposition: INLINE; FILENAME= "foo.html"
[csec: Both refer to 2183, and also mention: long filenames, dot and dotdot, absolute paths, mismatches between media type and extension]
This specification does not introduce any changes to the registration procedures for disposition values and parameters that are defined in Section 9 of [RFC2183].
|I registry (type: change, status: open)|
|email@example.com||2010-08-23||The registry technically is for the MIME header, but has been used for C-D in other protocols already. What's missing are instructions that new registrations should state which protocol they're for. Do we want to attempt to modify the registry?|
This document updates the definition of the Content-Disposition HTTP header field in the permanent HTTP header field registry (see [RFC3864]).
↑ I ↓
|[old-RFC2183]||Troost, R., Dorner, S., and K. Moore, “Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field”, RFC 2183, August 1997.|
|[RFC2119]||Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels”, BCP 14, RFC 2119, March 1997.|
|[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.|
|[draft-reschke-rfc2231-in-http]||Reschke, J., “Applicability of RFC 2231 Encoding to Hypertext Transfer Protocol (HTTP) Headers”, Internet-Draft draft-reschke-rfc2231-in-http-12 (work in progress), April 2010.|
|[RFC5987]||Reschke, J., “Applicability of RFC 2231 Encoding to Hypertext Transfer Protocol (HTTP) Headers”, RFC 5987, August 2010.|
|[RFC2183]||Troost, R., Dorner, S., and K. Moore, “Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field”, RFC 2183, August 1997.|
|[RFC2231]||Freed, N. and K. Moore, “MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations”, RFC 2231, November 1997.|
|[RFC3629]||Yergeau, F., “UTF-8, a transformation format of ISO 10646”, RFC 3629, STD 63, November 2003.|
|[RFC3864]||Klyne, G., Nottingham, M., and J. Mogul, “Registration Procedures for Message Header Fields”, BCP 90, RFC 3864, September 2004.|
|[RFC3986]||Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax”, RFC 3986, STD 66, January 2005.|
|[ISO-8859-1]||International Organization for Standardization, “Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1”, ISO/IEC 8859-1:1998, 1998.|
|[USASCII]||American National Standards Institute, “Coded Character Set -- 7-bit American Standard Code for Information Interchange”, ANSI X3.4, 1986.|
|[RFC2046]||Freed, N. and N. Borenstein, “Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types”, RFC 2046, November 1996.|
|[RFC2047]||Moore, K., “MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text”, RFC 2047, November 1996.|
Compared to Section 19.5.1 of [RFC2616], the following normative changes reflecting actual implementations have been made:
Section 2 of [RFC2183] defines several additional disposition parameters: "creation-date", "modification-date", "quoted-date-time", and "size". These do not appear to be implemented by any user agent, thus have been om↑ I ↓
mitted from this specification.
[rfc.comment.3: Mention: RFC 2047, IE, Safari]
Adjust terminology ("header" -> "header field"). Update rfc2231-in-http reference.