org.apache.juneau.http

Class AcceptEncoding

java.lang.Object

org.apache.juneau.http.HeaderRangeArray

org.apache.juneau.http.AcceptEncoding

public final class AcceptEncoding
extends HeaderRangeArray

Represents a parsed Accept-Encoding HTTP request header.

List of acceptable encodings.

Example

Accept-Encoding: gzip, deflate

RFC2616 Specification

The Accept-Encoding request-header field is similar to Accept, but restricts the content-codings (section 3.5) that are acceptable in the response.

Accept-Encoding = "Accept-Encoding" ":" 1#( codings [ ";" "q" "=" qvalue ] ) codings = ( content-coding | "*" )

Examples of its use are:

Accept-Encoding: compress, gzip Accept-Encoding: Accept-Encoding: * Accept-Encoding: compress;q=0.5, gzip;q=1.0 Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0

A server tests whether a content-coding is acceptable, according to an Accept-Encoding field, using these rules:

1. If the content-coding is one of the content-codings listed in the Accept-Encoding field, then it is acceptable, unless it is accompanied by a qvalue of 0. (As defined in section 3.9, a qvalue of 0 means "not acceptable.")
2. The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed in the header field.
3. If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero qvalue is preferred.
4. The "identity" content-coding is always acceptable, unless specifically refused because the Accept-Encoding field includes "identity;q=0", or because the field includes "*;q=0" and does not explicitly include the "identity" content-coding. If the Accept-Encoding field-value is empty, then only the "identity" encoding is acceptable.

If an Accept-Encoding field is present in a request, and if the server cannot send a response which is acceptable according to the Accept-Encoding header, then the server SHOULD send an error response with the 406 (Not Acceptable) status code.

If no Accept-Encoding field is present in a request, the server MAY assume that the client will accept any content coding. In this case, if "identity" is one of the available content-codings, then the server SHOULD use the "identity" content-coding, unless it has additional information that a different content-coding is meaningful to the client.

Note: If the request does not include an Accept-Encoding field, and if the "identity" content-coding is unavailable, then content-codings commonly understood by HTTP/1.0 clients (i.e.,"gzip" and "compress") are preferred; some older clients improperly display messages sent with other content-codings. The server might also make this decision based on information about the particular user-agent or client.

Note: Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. This means that qvalues will not work and are not permitted with x-gzip or x-compress.

See Also:

• Hypertext Transfer Protocol -- HTTP/1.1

Method Summary

Modifier and Type	Method and Description
static AcceptEncoding	forString(String value) Returns a parsed Accept-Encoding header.

Methods inherited from class org.apache.juneau.http.HeaderRangeArray

asSimpleRanges, findMatch, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

forString

public static AcceptEncoding forString(String value)

Returns a parsed Accept-Encoding header.

Parameters:

value - The Accept-Encoding header string.

Returns:

The parsed Accept-Encoding header, or null if the string was null.