Compile Apache Module - HTTP server extension - Add Server Variables to PHP
Adding a module to the Apache 2 HTTP web-server is actually pretty straightforward.
In fact it is pretty similar to a Linux Kernel module.
This module will just add a variable to the HTTP request - you can read the added
variables in e.g. PHP with the following PHP code:
<?
print $_SERVER{myvar};
?>
<hr>
<?
print apache_note("myvar");
?>
Compile the module:
gcc -fPIC -DSHARED_MODULE -I/usr/include/apache2 -I/usr/include/apr-0 -c mod_myvar.c
This will produce mod_myvar.o
Use the linker "ld" to make a shared object from the object file:
ld -Bshareable -o mod_myvar.so mod_myvar.o
Now copy the file to your apache modules directory:
cp mod_myvar.so /usr/lib/apache2/modules/
chmod 0755 /usr/lib/apache2/modules/mod_myvar.so
Now you need to make sure that Apache is loading the new module on startup.
So add this
LoadModule myvar_module /usr/lib/apache2/modules/mod_myvar.so
to your apache config, or create it as file in
/etc/apache2/mods-available/myvar.load
If you use the latter method, make sure you enable the module in mods-enabled:
# cd /etc/apache2/mods-enabled
# ln -s /etc/apache2/mods-available/myvar.load myvar.load
We're almost done! Just add the following stuff to your apache2.conf:
<IfModule mod_myvar.c>
MyVarEnable On
</IfModule>
This will enable the new module.
mod_myvar.c
#include "httpd.h"
#include "http_config.h"
#include "http_protocol.h"
#include "http_log.h"
#include "ap_config.h"
module AP_MODULE_DECLARE_DATA myvar_module;
static apr_status_t myvar_cleanup(void *cfgdata) {
// cleanup code here, if needed
return APR_SUCCESS;
}
static void myvar_child_init(apr_pool_t *p, server_rec *s) {
apr_pool_cleanup_register(p, NULL, myvar_cleanup, myvar_cleanup);
}
static int myvar_post_read_request(request_rec *r) {
char myvar[16] = "CAPTAIN WAS HERE";
apr_table_set(r->notes, "myvar", myvar); // PHP: apache_notes
apr_table_set( r->subprocess_env, "myvar", myvar ); // PHP: HTTP_SERVER_VARS
return OK;
}
static const char *set_myvar_enable(cmd_parms *cmd, void *dummy, int arg) {
ap_get_module_config(cmd->server->module_config, &myvar_module);
return NULL;
}
static const command_rec myvar_cmds[] = {
AP_INIT_FLAG( "MyVarEnable", set_myvar_enable, NULL, OR_FILEINFO, "Turn on mod_myvar"),
{NULL}
};
static void myvar_register_hooks(apr_pool_t *p) {
ap_hook_post_read_request( myvar_post_read_request, NULL, NULL, APR_HOOK_MIDDLE );
ap_hook_child_init( myvar_child_init, NULL, NULL, APR_HOOK_MIDDLE );
}
// API hooks
module AP_MODULE_DECLARE_DATA myvar_module = {
STANDARD20_MODULE_STUFF,
NULL, /* create per-dir config structures */
NULL, /* merge per-dir config structures */
NULL, /* create per-server config structures */
NULL, /* merge per-server config structures */
myvar_cmds, /* table of config file commands */
myvar_register_hooks /* register hooks */
};
Last-Modified: Sat, 04 Feb 2006 16:03:19 GMT
