| Individual Submission | J. Snell |
| Internet-Draft | December 2007 |
| Intended status: Informational | |
| Expires: June 2008 |
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This specification defines a new HTTP header that can be used by a client to request that certain behaviors be implemented by a server while processing a request.¶
This specification defines a new HTTP header that can be used by a client to request that certain behaviors be implemented by a server while processing a request.¶
The Prefer request-header is used to indicate that particular server behaviors are preferred, but not required, by the client. Prefer is similar in nature to the Expect header defined by [RFC2616] with the exception that servers are allowed to ignore a clients stated preferences.¶
Prefer = "Prefer" ":" 1#preference
preference = "return-no-content" | preference-extension
preference-extension = token [ "=" ( token | quoted-string )
*prefer-params ]
prefer-params = ";" token [ "=" ( token | quoted-string ) ]
This header is defined with an extensible syntax to allow for future extensions. A server that does not understand or is unable to comply with any of the preference values in the Prefer field of a request MUST ignore those values and MUST NOT stop processing or signal an error.¶
Comparison of preference values is case-insensitive for unquoted tokens and is case-sensitive for quoted-string preference-extensions.¶
The Prefer mechanism is hop-by-hop: that is, an HTTP proxy MAY choose to honor a preference even if the origin server does not. However, the Prefer request-header itself is end-to-end; it MUST be forwarded if the request is forwarded.¶
The "return-no-content" token indicates that the client prefers that the server not include an entity in the response to a successful request. Typically, such responses would use the 204 No Content status code as defined in Section 10.2.5 of [RFC2616], but other status codes can be used as appropriate.¶
Header field name: Prefer
Applicable Protocol: HTTP
Status: standard
Author/Change controller: IETF
Specification document: this specification
The author greatfully acknowledges the input from the IETF HTTP mailing list on the development of this document.¶
TODO¶
The RFC Editor should remove this section and the Changes section.¶
We need to determine how new preference codes are created/registered¶
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