A Sample Apache::Registry Script (Practical mod

2.6. A Sample Apache::Registry Script

Example 2-1. mod_perl_rules1.pl

print "Content-type: text/plain\n\n";
print "mod_perl rules!\n";

Example 2-2. mod_perl_rules1.pl with shebang line

#!/usr/bin/perl
print "Content-type: text/plain\n\n";
print "mod_perl rules!\n";

Now make the script executable and readable by the server, as explained in the previous section:

panic% chmod 0700 /home/stas/modperl/mod_perl_rules1.pl

The mod_perl_rules1.pl script can be tested from the command line, since it is essentially a regular Perl script:

panic% perl /home/stas/modperl/mod_perl_rules1.pl

This should produce the following output:

Content-type: text/plain

mod_perl rules!

Make sure the server is running and issue these requests using a browser:

http://localhost/perl/mod_perl_rules1.pl

If the port being used is not 80 (e.g., 8080), the port number should be included in the URL:

http://localhost:8080/perl/mod_perl_rules1.pl

Also, the localhost approach will work only if the browser is running on the same machine as the server. If not, use the real server name for this test. For example:

http://example.com/perl/mod_perl_rules1.pl

Figure 2-1. Testing the newly configured server

If you see it, congratulations! You have a working mod_perl server.

Example 2-3. mod_perl_rules2.pl

my $r = Apache->request;
$r->send_http_header('text/plain');
$r->print("mod_perl rules!\n");

The mod_perl API needs a request object, $r, to communicate with Apache. The script retrieves this object and uses it to send the HTTP header and print the irrefutable fact about mod_perl's coolness.

This script generates the same output as the previous one.

2.6.1. Porting Existing CGI Scripts to mod_perl

Now it's time to move any existing CGI scripts from the /somewhere/cgi-bin directory to /home/stas/modperl. Once moved, they should run much faster when requested from the newly configured base URL (/perl/). For example, a CGI script called test.pl that was previously accessed as /cgi-bin/test.pl can now be accessed as /perl/test.pl under mod_perl and the Apache::Registry module.

Some of the scripts might not work immediately and may require some minor tweaking or even a partial rewrite to work properly with mod_perl. We will talk in depth about these issues in Chapter 6. Most scripts that have been written with care and developed with warnings enabled and the strict pragma[15] will probably work without any modifications at all.

[15]Warnings and strict abort your script if you have written sloppy code, so that you won't be surprised by unknown, hidden bugs. Using them is generally considered a good thing in Perl and is very important in mod_perl.

A quick solution that avoids most rewriting or editing of existing scripts that do not run properly under Apache::Registry is to run them under Apache::PerlRun. This can be achieved by simply replacing Apache::Registry with Apache::PerlRun in httpd.conf. Put the following configuration directives instead in httpd.conf and restart the server:

Alias /perl/ /home/stas/modperl/
PerlModule Apache::PerlRun
<Location /perl/>
    SetHandler perl-script
    PerlHandler Apache::PerlRun
    Options ExecCGI
    PerlSendHeader On
    Allow from all
</Location>

Almost every script should now run without problems; the few exceptions will almost certainly be due to the few minor limitations that mod_perl or its handlers have, but these are all solvable and covered in Chapter 6.

As we saw in Chapter 1, Apache::PerlRun is usually useful while transitioning scripts to run properly under Apache::Registry. However, we don't recommend using Apache::PerlRun in the long term; although it is significantly faster than mod_cgi, it's still not as fast as Apache::Registry and mod_perl handlers.