HTTP Pocket Reference

Name

Accept-Encoding: encoding_types

Synopsis

Through the Accept-Encoding header, a client may specify what encoding algorithms it understands. If this header is omitted, the server will send the requested entity-body without any additional encoding. Encoding mechanisms can be used to reduce consumption of scarce resources, at the expense of less expensive resources. For example, large files may be compressed to reduce transmission time over slow network connections.

In the HTTP/1.0 specification, two encoding mechanisms are defined: x-gzip and x-compress. Multiple encoding schemes can be listed, separated by commas. For reasons of compatibility with historical practice, gzip and compress should be considered the same as x-gzip and x-compress.

Encoding Mechanism	Encoded By
gzip	Jean-Loup Gailly’s GNU zip compression scheme
compress	Modified Lempel-Ziv compression scheme
deflate	The deflate method found in PKWARE products

For example:

Accept-encoding: gzip

There is no guarantee that the requested encoding mechanism has been applied to the entity-body returned by the server. If the client specifies an Accept-encoding header, it should examine the server’s Content-encoding header to see if an encoding mechanism was applied. If the Content-encoding header has been omitted, no encoding mechanism was applied.