To understand mod_perl, you should understand how the Apache
server works. When Apache receives a request, it processes
it in several stages. First, it translates the URL to the
associated resource (i.e., filename, CGI script, etc.)
on the server machine. Then it checks to see
if the user is authorized to access that resource,
perhaps by requesting and checking an ID and password.
Once the user has passed inspection, the server figures out
what kind of data it’s sending back (e.g., it decides a
file ending in .html is probably a
file), creates some headers, and sends those headers
back to the client with the resource itself. When all is
said and done, the server makes a log entry.
At each stage of this process, Apache looks for routines to
“handle” the request. Apache supplies its own handlers;
for example, one of the default handlers is
often seen applied to /cgi-bin:
<Location /cgi-bin> ... SetHandler cgi-script ... </Location>
mod_perl allows you to write your own
handlers in Perl, by embedding the Perl runtime library directly
into the Apache httpd server executable.
To use mod_perl for CGI (which is all that most people
want to do with it), assign the
perl-script, and then assign the
to a special Perl module called Apache::Registry:
SetHandler perl-script PerlHandler Apache::Registry
PerlHandler is the mod_perl handler for the content retrieval stage of the transaction. To ...