NAME

       ModPerl::RegistryLoader - Compile ModPerl::RegistryCooker scripts at server startup

Synopsis

         # in startup.pl
         use ModPerl::RegistryLoader ();
         use File::Spec ();

         # explicit uri => filename mapping
         my $rlbb = ModPerl::RegistryLoader->new(
             package => 'ModPerl::RegistryBB',
             debug   => 1, # default 0
         );

         $rlbb->handler($uri, $filename);

         ###
         # uri => filename mapping using a helper function
         sub trans {
             my $uri = shift;
             $uri =~ s|^/registry/|cgi-bin/|;
             return File::Spec->catfile(Apache2::ServerUtil::server_root, $uri);
         }
         my $rl = ModPerl::RegistryLoader->new(
             package => 'ModPerl::Registry',
             trans   => \&trans,
         );
         $rl->handler($uri);

         ###
         $rlbb->handler($uri, $filename, $virtual_hostname);

Description

       This modules allows compilation of scripts, running under packages derived from
       "ModPerl::RegistryCooker", at server startup.  The script's handler routine is compiled by the parent
       server, of which children get a copy and thus saves some memory by initially sharing the compiled copy
       with the parent and saving the overhead of script's compilation on the first request in every httpd
       instance.

       This module is of course useless for those running the "ModPerl::PerlRun" handler, because the scripts
       get recompiled on each request under this handler.

Methods

       new()
           When   creating   a   new   "ModPerl::RegistryLoader"  object,  one  has  to  specify  which  of  the
           "ModPerl::RegistryCooker" derived modules to use. For example if a  script  is  going  to  run  under
           "ModPerl::RegistryBB" the object is initialized as:

             my $rlbb = ModPerl::RegistryLoader->new(
                 package => 'ModPerl::RegistryBB',
             );

           If the package is not specified "ModPerl::Registry" is assumed:

             my $rlbb = ModPerl::RegistryLoader->new();

           To turn the debugging on, set the debug attribute to a true value:

             my $rlbb = ModPerl::RegistryLoader->new(
                 package => 'ModPerl::RegistryBB',
                 debug   => 1,
             );

           Instead  of  specifying  explicitly  a filename for each uri passed to handler(), a special attribute
           trans can be set to a subroutine to perform automatic remapping.

             my $rlbb = ModPerl::RegistryLoader->new(
                 package => 'ModPerl::RegistryBB',
                 trans   => \&trans,
             );

           See the handler() item for an example of using the trans attribute.

       handler()
             $rl->handler($uri, [$filename, [$virtual_hostname]]);

           The handler() method takes argument of "uri" and optionally of "filename" and of "virtual_hostname".

           URI to filename translation normally doesn't happen until HTTP request time, so we're forced to  roll
           our own translation. If the filename is supplied it's used in translation.

           If  the  filename is omitted and a "trans" subroutine was not set in new(), the loader will try using
           the "uri" relative to the "ServerRoot" configuration directive.  For example:

             httpd.conf:
             -----------
             ServerRoot /usr/local/apache
             Alias /registry/ /usr/local/apache/cgi-bin/

             startup.pl:
             -----------
             use ModPerl::RegistryLoader ();
             my $rl = ModPerl::RegistryLoader->new(
                 package => 'ModPerl::Registry',
             );
             # preload /usr/local/apache/cgi-bin/test.pl
             $rl->handler(/registry/test.pl);

           To make the loader smarter about the URI->filename translation, you may provide the new() method with
           a trans() function to translate the uri to filename.

           The following example will pre-load all files ending with .pl in the cgi-bin  directory  relative  to
           "ServerRoot".

             httpd.conf:
             -----------
             ServerRoot /usr/local/apache
             Alias /registry/ /usr/local/apache/cgi-bin/

             startup.pl:
             -----------
             {
                 # test the scripts pre-loading by using trans sub
                 use ModPerl::RegistryLoader ();
                 use File::Spec ();
                 use DirHandle ();
                 use strict;

                 my $dir = File::Spec->catdir(Apache2::ServerUtil::server_root,
                                             "cgi-bin");

                 sub trans {
                     my $uri = shift;
                     $uri =~ s|^/registry/|cgi-bin/|;
                     return File::Spec->catfile(Apache2::ServerUtil::server_root,
                                                $uri);
                 }

                 my $rl = ModPerl::RegistryLoader->new(
                     package => "ModPerl::Registry",
                     trans   => \&trans,
                 );
                 my $dh = DirHandle->new($dir) or die $!;

                 for my $file ($dh->read) {
                     next unless $file =~ /\.pl$/;
                     $rl->handler("/registry/$file");
                 }
             }

           If  $virtual_hostname argument is passed it'll be used in the creation of the package name the script
           will be compiled into for those registry handlers that use namespace_from_uri() method.  See also the
           notes   on    $ModPerl::RegistryCooker::NameWithVirtualHost    in    the    "ModPerl::RegistryCooker"
           documentation.

           Also explained in the "ModPerl::RegistryLoader" documentation, this only has an effect at run time if
           $ModPerl::RegistryCooker::NameWithVirtualHost   is  set  to  true,  otherwise  the  $virtual_hostname
           argument is ignored.

Implementation Notes

       "ModPerl::RegistryLoader" performs a very simple job, at run time it loads  and  sub-classes  the  module
       passed  via  the  package  attribute  and  overrides  some  of  its  functions,  to  emulate the run-time
       environment. This allows one to preload the same script into different registry environments.

Authors

       The original "Apache2::RegistryLoader" implemented by Doug MacEachern.

       Stas Bekman did the porting to the new registry framework based on "ModPerl::RegistryLoader".

SEE ALSO

       "ModPerl::RegistryCooker",  "ModPerl::Registry",  "ModPerl::RegistryBB",  "ModPerl::PerlRun",  Apache(3),
       mod_perl(3)

perl v5.38.2                                       2024-04-07              libapache2-mod...:RegistryLoader(3pm)