info guile

7.3.4.4 Request Headers

Request headers may only appear in an HTTP request, not in a response.

HTTP Header: List accept

A list of preferred media types for a response. Each element of the list is itself a list, in the same format as content-type.

(parse-header 'accept "text/html,text/plain;charset=utf-8")
⇒ ((text/html) (text/plain (charset . "utf-8")))

Preference is expressed with quality values:

(parse-header 'accept "text/html;q=0.8,text/plain;q=0.6")
⇒ ((text/html (q . 800)) (text/plain (q . 600)))

HTTP Header: QList accept-charset

A quality list of acceptable charsets. Note again that what HTTP calls a “charset” is what Guile calls a “character encoding”.

(parse-header 'accept-charset "iso-8859-5, unicode-1-1;q=0.8")
⇒ ((1000 . "iso-8859-5") (800 . "unicode-1-1"))

HTTP Header: QList accept-encoding

A quality list of acceptable content codings.

(parse-header 'accept-encoding "gzip,identity=0.8")
⇒ ((1000 . "gzip") (800 . "identity"))

HTTP Header: QList accept-language

A quality list of acceptable languages.

(parse-header 'accept-language "cn,en=0.75")
⇒ ((1000 . "cn") (750 . "en"))

HTTP Header: Pair authorization

Authorization credentials. The car of the pair indicates the authentication scheme, like basic. For basic authentication, the cdr of the pair will be the base64-encoded ‘user:pass’ string. For other authentication schemes, like digest, the cdr will be a key-value list of credentials.

(parse-header 'authorization "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
⇒ (basic . "QWxhZGRpbjpvcGVuIHNlc2FtZQ==")

HTTP Header: List expect

A list of expectations that a client has of a server. The expectations are key-value lists.

(parse-header 'expect "100-continue")
⇒ ((100-continue))

HTTP Header: String from

The email address of a user making an HTTP request.

(parse-header 'from "bob@example.com")
⇒ "bob@example.com"

HTTP Header: Pair host

The host for the resource being requested, as a hostname-port pair. If no port is given, the port is #f.

(parse-header 'host "gnu.org:80")
⇒ ("gnu.org" . 80)
(parse-header 'host "gnu.org")
⇒ ("gnu.org" . #f)

HTTP Header: *|List if-match

A set of etags, indicating that the request should proceed if and only if the etag of the resource is in that set. Either the symbol *, indicating any etag, or a list of entity tags.

(parse-header 'if-match "*")
⇒ *
(parse-header 'if-match "asdfadf")
⇒ (("asdfadf" . #t))
(parse-header 'if-match W/"asdfadf")
⇒ (("asdfadf" . #f))

HTTP Header: Date if-modified-since

Indicates that a response should proceed if and only if the resource has been modified since the given date.

(parse-header 'if-modified-since "Tue, 15 Nov 1994 08:12:31 GMT")
⇒ #<date ...>

HTTP Header: *|List if-none-match

A set of etags, indicating that the request should proceed if and only if the etag of the resource is not in the set. Either the symbol *, indicating any etag, or a list of entity tags.

(parse-header 'if-none-match "*")
⇒ *

HTTP Header: ETag|Date if-range

Indicates that the range request should proceed if and only if the resource matches a modification date or an etag. Either an entity tag, or a SRFI-19 date.

(parse-header 'if-range "\"original-etag\"")
⇒ ("original-etag" . #t)

HTTP Header: Date if-unmodified-since

Indicates that a response should proceed if and only if the resource has not been modified since the given date.

(parse-header 'if-not-modified-since "Tue, 15 Nov 1994 08:12:31 GMT")
⇒ #<date ...>

HTTP Header: UInt max-forwards

The maximum number of proxy or gateway hops that a request should be subject to.

(parse-header 'max-forwards "10")
⇒ 10

HTTP Header: Pair proxy-authorization

Authorization credentials for a proxy connection. See the documentation for authorization above for more information on the format.

(parse-header 'proxy-authorization "Digest foo=bar,baz=qux"
⇒ (digest (foo . "bar") (baz . "qux"))

HTTP Header: Pair range

A range request, indicating that the client wants only part of a resource. The car of the pair is the symbol bytes, and the cdr is a list of pairs. Each element of the cdr indicates a range; the car is the first byte position and the cdr is the last byte position, as integers, or #f if not given.

(parse-header 'range "bytes=10-30,50-")
⇒ (bytes (10 . 30) (50 . #f))

HTTP Header: URI referer

The URI of the resource that referred the user to this resource. The name of the header is a misspelling, but we are stuck with it.

(parse-header 'referer "http://www.gnu.org/")
⇒ #<uri ...>

HTTP Header: List te

A list of transfer codings, expressed as key-value lists. A common transfer coding is trailers.

(parse-header 'te "trailers")
⇒ ((trailers))

HTTP Header: String user-agent

A string indicating the user agent making the request. The specification defines a structured format for this header, but it is widely disregarded, so Guile does not attempt to parse strictly.

(parse-header 'user-agent "Mozilla/5.0")
⇒ "Mozilla/5.0"

This document was generated on April 20, 2013 using texi2html 5.0.