platform agnostic

A mod_perl handler can parse the incoming client request (querystring, form post data etc) using Apache2::Request. It is *not* installed when you install mod_perl. Getting it working is a 3 step process.

First issue the following command:

sudo apt-get install libapreq2

This installs 2 things – the libapreq2 shared library, and an Apache module – mod_apreq2.

Next we install the Perl bindings – Apache2::Request – which we use in our handler code.

sudo apt-get install libapache2-request-perl

At this stage if you restart Apache, it will load your Perl handler without any complaints. However if you visit a handler that uses Apache2::Request, it’ll error out with the following entry in error.log:


/usr/sbin/apache2: symbol lookup error: /usr/lib/perl5/auto/APR/Request/Apache2/Apache2.so: undefined symbol: apreq_handle_apache2


This is because unlike our mod_perl installation, apt-get doesn’t enable mod_apreq2 after installing it. We enable it manually by creating a symbolic link to /etc/apache2/mods-available/apreq.load under /etc/apache2/mods-enabled/:


sudo bash
cd /etc/apache2/mods-enabled
ln -s ../mods-available/apreq.load
apache2ctl restart


Updated: You can also run a2enmod to enable an Apache module and use a2dismod to disable it.

Visit your handler url again and this time it should work withour errors. Here is the modified handler from the mod_perl installation post that now uses Apache2::Request to enable you to test if your installation is working correctly:

package Hello;
use strict;

use Apache2::RequestRec ();
use Apache2::RequestIO ();

use Apache2::Const -compile => qw(OK);

use Apache2::Request;

sub handler {
    my $r = shift;

    $r->content_type('text/plain');

    my $req = Apache2::Request->new($r);
    my $name = $req->param("name");
    $name = $name ? $name : "World";

    print "Hello $name, the time here is " . localtime() . "\n";

    return Apache2::Const::OK;
}

1;

configuration, installation, perl, ubuntu Apache2::Request, libapreq2, mod_apreq2, mod_perl