Related Modules mod_ext_filter mod_include |
Related Directives ExtFilterDefine ExtFilterOptions SetInputFilter SetOutputFilter |
A filter is a process which is applied to data that is sent or received by the server. Data sent by clients to the server is processed by input filters while data sent by the server to the client is processed by output filters. Multiple filters can be applied to the data, and the order of the filters can be explicitly specified.
Filters are used internally by Apache to perform functions such as
chunking and byte-range request handling. In addition, modules can
provide filters which are selectable using run-time configuration
directives. The set of filters which apply to data can be manipulated
with the SetInputFilter
and SetOutputFilter
directives.
The only configurable filter currently included with the Apache
distribution is the INCLUDES
filter which is provided by
mod_include to process output for
Server Side Includes. There is also an experimental module called mod_ext_filter which allows for
external programs to be defined as filters.