Introduction to mod_perl (part 2): mod_perl Quickstart - The "mod_perl rules" Apache::Registry Script (
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As you probably know,
mod_perl allows you to re-use CGI scripts written in Perl which were previously
used under mod_cgi. Therefore our first test script can be as simple as:
print "Content-type: text/plain\r\n\r\n";
print "mod_perl rules!\n";
Save this script in the /home/httpd/perl/mod_perl_rules1.pl file. Notice
that the shebang line is not needed with mod_perl, but you can keep it if you
want. So the following script can be used as well:
#!/usr/bin/perl
print "Content-type: text/plain\r\n\r\n";
print "mod_perl rules!\n";
Of course you can write the same script using the Apache Perl API:
my $r = shift;
$r->send_http_header('text/plain');
$r->print("mod_perl rules!\n");
Save this script in the /home/httpd/perl/mod_perl_rules2.pl
file.
Now make both of the scripts executable and readable by the server.
Remember that when you execute scripts from a shell, they are being executed by
the user-name you are logged with. When instead you try to run the scripts by
issuing requests, Apache needs to be able to read and execute them. So we make
the script readable and executable by everybody:
% chmod 0755 /home/httpd/perl/mod_perl_rules1.pl \
/home/httpd/perl/mod_perl_rules2.pl
If you don't want other users to be able to read your script, you should
add yourself into the groupname the webserver is running with (as defined by the
Group directive) and then make the script owned by that group and then you can
tighten the permissions. For example on my machine I run the server under the
group httpd and I'm the only one who is in the same group, so I can do the
following:
% chown stas.httpd /home/httpd/perl/mod_perl_rules1.pl \
/home/httpd/perl/mod_perl_rules2.pl
% chmod 0750 /home/httpd/perl/mod_perl_rules1.pl \
/home/httpd/perl/mod_perl_rules2.pl
The first command makes the files belong to group httpd, the second sets
the proper execution and read permissions.
That's secure, assuming that
you have a dedicated groupname for your server, of course.
Also remember
that all the directories that lead to the script should be readable and
executable by the server.
You can test mod_perl_rules1.pl from the
command line, since it is essentially a regular Perl script.
% perl /home/httpd/perl/mod_perl_rules1.pl
You should see the following output:
mod_perl rules!
You cannot test the second script by executing it from the command line
since it uses the mod_perl API which is available only when run from within the
mod_perl server.
Make sure the server is running and issue these requests
using your favorite
browser:
http://localhost/perl/mod_perl_rules1.pl
http://localhost/perl/mod_perl_rules2.pl
In
both cases you will see on the following response:
mod_perl rules!
If you see it--congratulations! You have a working mod_perl
server.
If you're using port 8080 instead of 80, you should use this
number in the
URL:
http://localhost:8080/perl/mod_perl_rules1.pl
http://localhost:8080/perl/mod_perl_rules2.pl
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://your.server.name/perl/mod_perl_rules1.pl
If there
is any problem please refer to the error_log file for the error
reports.
Now it's a time to move your CGI scripts from /somewhere/cgi-bin
directory to /home/httpd/perl/ and see them running much much faster, when
requested from the newly configured base URL (/perl/). If you were accessing the
script as /cgi-bin/test.pl, it will now be accessed from
/perl/test.pl.
Some of your scripts might not work immediately and will
require some minor tweaking or even a partial rewrite to work properly with
mod_perl. Chances are that if you are not practicing sloppy programming, the
scripts will work without any modifications at all.
If you have a problem
with your scripts, a good approach is to replace Apache::Registry with
Apache::PerlRun in httpd.conf, as the latter can execute really badly written
scripts. Put the following configuration directives instead in httpd.conf and
restart the server:
PerlModule Apache::PerlRun
<Location /perl>
SetHandler perl-script
PerlHandler Apache::PerlRun
Options ExecCGI
PerlSendHeader On
allow from all
</Location>
Now your scripts should work for sure, unless there is something in them
mod_perl doesn't accept. We will discuss these nuances in future articles.
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