## AddEncoding

Syntax: AddEncoding MIME-enc extension extension...
Context: server config, virtual host, directory, .htaccess
Override: FileInfo
Status: Base
Module: mod_mime

The AddEncoding directive maps the given filename extensions to the specified encoding type. MIME-enc is the MIME encoding to use for documents containing the extension. This mapping is added to any already in force, overriding any mappings that already exist for the same extension. Example:

> `AddEncoding x-gzip gz
> AddEncoding x-compress Z`

This will cause filenames containing the .gz extension to be marked as encoded using the x-gzip encoding, and filenames containing the .Z extension to be marked as encoded with x-compress.

Old clients expect `x-gzip` and `x-compress`, however the standard dictates that they're equivalent to `gzip` and `compress` respectively. Apache does content encoding comparisons by ignoring any leading `x-`. When responding with an encoding Apache will use whatever form (i.e., `x-foo` or `foo`) the client requested. If the client didn't specifically request a particular form Apache will use the form given by the `AddEncoding` directive. To make this long story short, you should always use `x-gzip` and `x-compress` for these two specific encodings. More recent encodings, such as `deflate` should be specified without the `x-`.

See also: Files with multiple extensions