|identifier||This is a string that you use as the name for the variant. This identifier for the preferred variants returned by choose().|
This is a number between 0.000 and 1.000 that describes the source
quality. This is what draft-ietf-http-v11-spec-00.ps says about this
Source quality is measured by the content provider as representing the amount of degradation from the original source. For example, a picture in JPEG form would have a lower qs when translated to the XBM format, and much lower qs when translated to an ASCII-art representation. Note, however, that this is a function of the source - an original piece of ASCII-art may degrade in quality if it is captured in JPEG form. The qs values should be assigned to each variant by the content provider; if no qs value has been assigned, the default is generally qs=1.
This is the media type of the variant. The media type does not
include a charset attribute, but might contain other parameters.
This is one or more content encodings that has been applied to the
variant. The content encoding is generally used as a modifier to the
content media type. The most common content encodings are:
This is the character set used when the variant contains text.
The charset value should generally be undef or one of these:
This describes one or more languages that are used in the variant.
Language is described like this in draft-ietf-http-v11-spec-00.ps: A
language is in this context a natural language spoken, written, or
otherwise conveyed by human beings for communication of information to
other human beings. Computer languages are explicitly excluded.
The language tags are defined by RFC 3066. Examples are:
|content-length||This is the number of bytes used to represent the content.|
The following Accept* headers can be used for describing content preferences in a request (This description is an edited extract from draft-ietf-http-v11-spec-00.ps):
Accept This header can be used to indicate a list of media ranges which are acceptable as a response to the request. The * character is used to group media types into ranges, with */* indicating all media types and type/* indicating all subtypes of that type.
The parameter q is used to indicate the quality factor, which represents the users preference for that range of media types. The parameter mbx gives the maximum acceptable size of the response content. The default values are: q=1 and mbx=infinity. If no Accept header is present, then the client accepts all media types with q=1.
Accept: audio/*;q=0.2;mbx=200000, audio/basic
Accept-Charset Used to indicate what character sets are acceptable for the response. The us-ascii character set is assumed to be acceptable for all user agents. If no Accept-Charset field is given, the default is that any charset is acceptable. Example:
Accept-Charset: iso-8859-1, unicode-1-1
Accept-Encoding Restricts the Content-Encoding values which are acceptable in the response. If no Accept-Encoding field is present, the server may assume that the client will accept any content encoding. An empty Accept-Encoding means that no content encoding is acceptable. Example:
Accept-Encoding: compress, gzip
Accept-Language This field is similar to Accept, but restricts the set of natural languages that are preferred in a response. Each language may be given an associated quality value which represents an estimate of the users comprehension of that language. For example:
Accept-Language: no, en-gb;q=0.8, de;q=0.55
would mean: "I prefer Norwegian, but will accept British English (with 80% comprehension) or German (with 55% comprehension).
Copyright 1996,2001 Gisle Aas.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Gisle Aas <email@example.com>
|perl v5.20.3||HTTP::NEGOTIATE (3)||2012-02-18|