It is not enough to know that mod_perl is installed—the server
needs to be configured for mod_perl as well. Refer to Chapter 4 to learn about mod_perl configuration.
3.10.2. Testing by Viewing /perl-status
Assuming that you have configured the
<Location /perl-status>section in the
server configuration file as explained in Chapter 9, fetch
http://www.example.com/perl-status/ using your
favorite browser.
You should see something like this:
Embedded Perl version 5.6.1 for Apache/1.3.24 (Unix)
mod_perl/1.26 process 50880,
running since Sat May 18 18:08:01 2002
3.10.3. Testing via Telnet
Knowing the port you have configured Apache to
listen on, you can use Telnet to talk directly to
it.
Assuming that your mod_perl-enabled server listens to port
8080,[22] telnet to your server at port 8080,
type HEAD /
HTTP/1.0, and then press the Enter key twice:
[22]If in doubt, try port 80, which is the standard
HTTP port.
panic% telnet localhost 8080
HEAD / HTTP/1.0
You should see a response like this:
HTTP/1.1 200 OK
Date: Mon, 06 May 2002 09:49:41 GMT
Server: Apache/1.3.24 (Unix) mod_perl/1.26
Connection: close
Content-Type: text/html; charset=iso-8859-1
Connection closed.
The line:
Server: Apache/1.3.24 (Unix) mod_perl/1.26
confirms that you have mod_perl installed and that its version is
1.26.
3.10.4. Testing via a CGI Script
Another method
to test for mod_perl is to invoke a
CGI script that dumps the server's environment.
We assume that you have configured the server so that scripts running
under the location /perl/ are handled by the
Apache::Registry handler and that you have the
PerlSendHeader directive set to
On.
Copy and paste the script below. Let's say you name
it test.pl and save it at the root of the CGI
scripts, which is mapped directly to the /perl
location of your server.
print "Content-type: text/plain\n\n";
print "Server's environment\n";
foreach ( keys %ENV ) {
print "$_\t$ENV{$_}\n";
}
Make it readable and executable by the server (you may need to tune
these permissions on a public host):
panic% chmod a+rx test.pl
Now fetch the URL
http://www.example.com:8080/perl/test.pl
(replacing 8080 with the port your mod_perl-enabled server is
listening to). You should see something like this (the output has
been edited):
SERVER_SOFTWARE Apache/1.3.24 (Unix) mod_perl/1.26
GATEWAY_INTERFACE CGI-Perl/1.1
DOCUMENT_ROOT /home/httpd/docs
REMOTE_ADDR 127.0.0.1
[more environment variables snipped]
MOD_PERL mod_perl/1.21_01-dev
[more environment variables snipped]
If you see the that the value of GATEWAY_INTERFACE
is CGI-Perl/1.1, everything is OK.
If there is an error, you might have to add a shebang line
(#!/usr/bin/perl) as the first line of the CGI
script and then try it again. If you see:
GATEWAY_INTERFACE CGI/1.1
it means you have configured this location to run under mod_cgi and
not mod_perl.
Also note that there is a $ENV{MOD_PERL}
environment variable if you run under a mod_perl handler. This
variable is set to the mod_perl/1.xxstring, where
1.xx is the version number of mod_perl.
Based on this difference, you can write code like this:
BEGIN {
# perl5.004 or better is a must under mod_perl
require 5.004 if $ENV{MOD_PERL};
}
If you develop a generic Perl module aimed at mod_perl, mod_cgi, and
other runtime environments, this information comes in handy, because
it allows you to do mod_perl-specific things when running under
mod_perl. For example, CGI.pm is mod_perl-aware:
when CGI.pm knows that it is running under
mod_perl, it registers a cleanup handler for its global
$Q object, retrieves the query string via
Apache->request->args, and does a few other
things differently than when it runs under mod_cgi.
3.10.5. Testing via lwp-request
Assuming you have the
libwww-perl (LWP) package
installed, you can run the following tests. (Most likely you do have
it installed, since you need it to pass mod_perl's
make test.)
panic% lwp-request -e -d http://www.example.com
This shows you just the headers; the -d option
disables printing the response content. If you just want to see the
server version, try:
panic% lwp-request -e -d http://www.example.com | egrep '^Server:'
Of course, you should use
http://www.example.com:port_number if your
server is listening to a port other than port 80.
