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Apache HTTP Server Version 2.4

Apache > HTTP Server > Documentation > Version 2.4 > Modules

Apache Module mod_example_hooks

Description:	Illustrates the Apache module API
Status:	Experimental
Module Identifier:	example_hooks_module
Source File:	mod_example_hooks.c

Summary

The files in the modules/examples directory under the Apache distribution directory tree are provided as an example to those that wish to write modules that use the Apache API.

The main file is mod_example_hooks.c, which illustrates all the different callback mechanisms and call syntaxes. By no means does an add-on module need to include routines for all of the callbacks - quite the contrary!

The example module is an actual working module. If you link it into the server, enable the "example-hooks-handler" handler for a location, and then browse to that location, we will see a display of some of the tracing the example module did as the various callbacks were made.

Topics

• Compiling the example_hooks module
• Using the mod_example_hooks Module

Directives

• Example

Bugfix checklist

• httpd changelog
• Known issues
• Report a bug

See also

• Comments

Compiling the example_hooks module

To include the example_hooks module in the server, follow the steps below:

1. Run configure with --enable-example-hooks option.
2. Make the server (run "make").

To add another module of your own:

1. cp modules/examples/mod_example_hooks.c modules/new_module/mod_myexample.c
2. Modify the file.
3. Create modules/new_module/config.m4.
   1. Add APACHE_MODPATH_INIT(new_module).
   2. Copy APACHE_MODULE line with "example_hooks" from modules/examples/config.m4.
   3. Replace the first argument "example_hooks" with myexample.
   4. Replace the second argument with brief description of your module. It will be used in configure --help.
   5. If your module needs additional C compiler flags, linker flags or libraries, add them to CFLAGS, LDFLAGS and LIBS accordingly. See other config.m4 files in modules directory for examples.
   6. Add APACHE_MODPATH_FINISH.
4. Create module/new_module/Makefile.in. If your module doesn't need special build instructions, all we need to have in that file is include $(top_srcdir)/build/special.mk.
5. Run ./buildconf from the top-level directory.
6. Build the server with --enable-myexample

Using the mod_example_hooks Module

To activate the example_hooks module, include a block similar to the following in your httpd.conf file:

<Location "/example-hooks-info">
   SetHandler example-hooks-handler
</Location>

As an alternative, we can put the following into a .htaccess file and then request the file "test.example" from that location:

AddHandler example-hooks-handler ".example"

After reloading/restarting the server, we should be able to browse to this location and see the brief display mentioned earlier.

Example Directive

Description:	Demonstration directive to illustrate the Apache module API
Syntax:	Example
Context:	server config, virtual host, directory, .htaccess
Status:	Experimental
Module:	mod_example_hooks

The Example directive just sets a demonstration flag which the example module's content handler displays. It takes no arguments. If you browse to an URL to which the example-hooks content-handler applies, we will get a display of the routines within the module and how and in what order they were called to service the document request. The effect of this directive one can observe under the point "Example directive declared here: YES/NO".