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|ModPerl::Registry - Run unaltered CGI scripts persistently under mod_perl|
mod_perl2 User's Guide
By Stas Bekman, Jim Brandt
By Stas Bekman, Eric Cholet
# httpd.conf PerlModule ModPerl::Registry Alias /perl/ /home/httpd/perl/ <Location /perl> SetHandler perl-script PerlResponseHandler ModPerl::Registry #PerlOptions +ParseHeaders #PerlOptions -GlobalRequest Options +ExecCGI </Location>
URIs in the form of
http://example.com/perl/test.pl will be
compiled as the body of a Perl subroutine and executed. Each child
process will compile the subroutine once and store it in memory. It
will recompile it whenever the file (e.g. test.pl in our example)
is updated on disk. Think of it as an object oriented server with
each script implementing a class loaded at runtime.
The file looks much like a "normal" script, but it is compiled into a subroutine.
my $r = Apache2::RequestUtil->request; $r->content_type("text/html"); $r->send_http_header; $r->print("mod_perl rules!");
XXX: STOPPED here. Below is the old Apache::Registry document which I haven't worked through yet.
META: document that for now we don't chdir() into the script's dir,
because it affects the whole process under
should be used by those who run only under prefork MPM.
This module emulates the CGI environment, allowing programmers to write scripts that run under CGI or mod_perl without change. Existing CGI scripts may require some changes, simply because a CGI script has a very short lifetime of one HTTP request, allowing you to get away with "quick and dirty" scripting. Using mod_perl and ModPerl::Registry requires you to be more careful, but it also gives new meaning to the word "quick"!
Be sure to read all mod_perl related documentation for more details, including instructions for setting up an environment that looks exactly like CGI:
print "Content-type: text/html\n\n"; print "Hi There!";
Note that each httpd process or "child" must compile each script once, so the first request to one server may seem slow, but each request there after will be faster. If your scripts are large and/or make use of many Perl modules, this difference should be noticeable to the human eye.
If you are trying setup a DirectoryIndex under a Location covered by ModPerl::Registry* you might run into some trouble.
META: if this gets added to core, replace with real documenation. See http://marc.theaimsgroup.com/?l=apache-modperl&m=112805393100758&w=2
BEGIN blocks defined in scripts running under the
ModPerl::Registry handler behave similarly to the normal mod_perl handlers plus:
Only once, if pulled in by the parent process via
An additional time, once per child process or Perl interpreter, each time the script file changes on disk.
BEGIN blocks defined in modules loaded from
scripts behave identically to the normal mod_perl handlers, regardless
of whether they define a package or not.
END blocks encountered during compilation of a script, are called
after the script has completed its run, including subsequent
invocations when the script is cached in memory. This is assuming that
the script itself doesn't define a package on its own. If the script
defines its own package, the
END blocks in the scope of that
package will be executed at the end of the interpretor's life.
END blocks residing in modules loaded by registry script will be
executed only once, when the interpreter exits.
ModPerl::Registry::handler performs the same sanity checks as
mod_cgi does, before running the script.
The Apache function `exit' overrides the Perl core built-in function.
Normally when a Perl script is run from the command line or under CGI, arguments on the `#!' line are passed to the perl interpreter for processing.
ModPerl::Registry currently only honors the -w switch and will
warnings pragma in such case.
Another common switch used with CGI scripts is -T to turn on taint checking. This can only be enabled when the server starts with the configuration directive:
However, if taint checking is not enabled, but the -T switch is
ModPerl::Registry will write a warning to the error_log
You may set the debug level with the $ModPerl::Registry::Debug bitmask
1 => log recompile in errorlog 2 => ModPerl::Debug::dump in case of $@ 4 => trace pedantically
ModPerl::Registry makes things look just the CGI environment, however, you
must understand that this *is not CGI*. Each httpd child will compile
your script into memory and keep it there, whereas CGI will run it once,
cleaning out the entire process space. Many times you have heard
-w, always use
-w and 'use strict'".
This is more important here than anywhere else!
Some other important caveats to keep in mind are discussed on the
Perl Reference page.
Andreas J. Koenig, Doug MacEachern and Stas Bekman.