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Apache HTTP Server
Apache's Handler Use
A "handler" is an internal Apache representation of the action to be performed
when a file is called. Generally, files have implicit handlers, based on the file type.
Normally, all files are simply served by the server, but certain file types are
"handled" separately.
Apache 1.1 adds the ability to use handlers explicitly. Based on either filename extensions
or on location, handlers can be specified without relation to file type. This is advantageous
both because it is a more elegant solution, and because it also allows for both a type and
a handler to be associated with a file. (See also
Files with Multiple
Extensions.)
Handlers can either be built into the server or included in a module, or they can be added
with the Action
directive. The built-in handlers in the standard distribution are as follows:
- default-handler: Send the file using the
default_handler(),
which is the handler used by default to handle static content. (core)
- send-as-is: Send file with HTTP headers as is. (mod_asis)
- cgi-script: Treat the file as a CGI script. (mod_cgi)
- imap-file: Parse as an imagemap rule file. (mod_imap)
- server-info: Get the server's configuration information. (mod_info)
- server-parsed: Parse for server-side includes. (mod_include)
- server-status: Get the server's status report. (mod_status)
- type-map: Parse as a type map file for content negotiation. (mod_negotiation)
Modifying static content using a CGI script
The following directives will cause requests for files with the html extension
to trigger the launch of the footer.pl CGI script.
Action add-footer /cgi-bin/footer.pl
AddHandler add-footer .html
Then the CGI script is responsible for sending the originally requested document (pointed
to by the PATH_TRANSLATED environment variable) and making whatever modifications
or additions are desired.
Files with HTTP headers
The following directives will enable the send-as-is handler, which is used for
files which contain their own HTTP headers. All files in the /web/htdocs/asis/
directory will be processed by the send-as-is handler, regardless of their
filename extensions.
<Directory /web/htdocs/asis>
SetHandler send-as-is
</Directory>
In order to implement the handler features, an addition has been made to the
Apache API that you may wish to make use
of. Specifically, a new record has been added to the request_rec structure:
char *handler
If you wish to have your module engage a handler, you need only to set r->handler
to the name of the handler at any time prior to the invoke_handler stage of the
request. Handlers are implemented as they were before, albeit using the handler name instead
of a content type. While it is not necessary, the naming convention for handlers is to use a
dash-separated word, with no slashes, so as to not invade the media type name-space.
Apache HTTP Server
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