ModPerlEngineContrib

Permits Foswiki to be executed under mod_perl

Overview

This is a runtime engine component from Foswiki Standalone architecture.

mod_perl is the Perl API to the Apache web server. It permits hooking applications into Apache, providing good performance and great flexibility.

It has better performance than CGI because it loads and compiles apps at Apache initialization and apps are kept in memory as long as Apache itself, so there is no need to fork+load+compile all the code for each request.

Installation Instructions

As of Foswiki 2.0, ModPerlEngineContrib is installed by default. Show all Foswiki 1.x instructions

Visit the apache config generator and fill in the fields according to your environment. Select mod_perl as your Runtime Engine and choose your apache version. Push the Update config file button and you'll get your config file.

In the web server configuration, you will need to load mod_perl but it is also recommended to load the Apache HTTP Request Library (module apreq). If apreq is not loaded, the following error may be encountered in certain situations, e.g., during login:

apache2: symbol lookup error: /usr/lib/perl5/auto/APR/Request/Apache2/Apache2.so: undefined symbol: apreq_handle_apache2

Confirming mod_perl installation

On Foswiki 2.0 systems. visit FoswikiServerInformation. Look for the Engine entry in the General execution environment table.

Another technique to see which modules are enabled is using apache2ctl

$ apache2ctl -M | grep perl_module
 perl_module (shared)

If not found, enable mod_perl with

$ a2enmod mod_perl

Foswiki configuration tuning

Forking new processes under mod_perl can be very slow, so some configuration changes are recommended.

Access the configure script. (On Foswiki 1.x, you will need to click the Yes, I've read all the documentation button to show the expert settings.) Go to Store Settings:

• Store Implementation: If using RCS, adjust to RcsLite. (If using the PlainFile store, no change is needed.)
• Search Algorithm: use Foswiki::Store::SearchAlgorithms::PurePerl or Foswiki:Extensions/NativeSearchContrib

mod_perl configuration tuning

mod_perl limits the size of attachments to 64M by default. Set the APREQ2_ReadLimit to the maximum expected upload to permit larger attachments.

Note that this should be kept in sync with the Foswiki ATTACHFILESIZELIMIT, set in SitePreferences, default taken from SitePreferences.

<IfModule mod_perl.c>
   PerlSwitches -wT    # DO NOT USE THIS with Foswiki 2.0
   # mod_perl_startup.pl must exist, otherwise Apache will not start.
   PerlRequire "/var/www/foswiki/tools/mod_perl_startup.pl"
   APREQ2_ReadLimit  104857600
</IfModule>

Known Issues

• You must restart Apache in order for configuration changes take effect.

• If you are using some extension that add files to the bin/ directory, you may face problems as they were not designed to be executed under mod_perl. You should configure them to be run as plain CGI scripts. You can replace Files directive by FilesMatch and list all the exceptions.

   <FilesMatch "[script name needing CGI].*">
      SetHandler cgi-script
      .
      .
   </FilesMatch>

List of Files

File	Description
data/System/ModPerlEngineContrib.txt	Documentation
lib/Foswiki/Contrib/ModPerlEngineContrib/DEPENDENCIES
lib/Foswiki/Contrib/ModPerlEngineContrib.pm	Perl module
lib/Foswiki/Engine/Apache.pm	Perl module
lib/Foswiki/Engine/Apache/MP13.pm	Perl module
lib/Foswiki/Engine/Apache2.pm	Perl module
lib/Foswiki/Engine/Apache2/MP20.pm	Perl module
tools/mod_perl_startup.pl	Perl script

Dependencies

Name	Version	Description
mod_perl2	>=2.0	Optional, but required if you're using Apache 2.x and plan to enable mod_perl
Apache2::Request	>=2.0	Optional, but recommended if you're using Apache 2.x and plan to enable mod_perl

Change History

06 Aug 2023 (1.08)	Foswikitask:Item15151: add warnings and strictness
08 Dec 2017 (1.06)	Foswikitask:Item14544: SCRIPTURL breaks when X-FORWARDED-HOST has multiple values (partial fix).
30 Apr 2017 (1.05)	Foswikitask:Item14381: Preserver URL Encoding of the Foswiki URI.
26 Nov 2016 (1.04)	Released with Foswiki 2.1.3. Old Apache 1.x modules have been removed from the DEPENDENCIES file.
08 Apr 2016 (1.03)	Foswikitask:Item14022 Change foswiki.org links to https.
16 Jan 2016 (1.02)	Foswikitask:Item13926 Fix backwards compatibility with Foswiki 1.1.
20 Oct 2015 (1.01)	Released with Foswiki 2.0.3. Foswikitask:Item13830: Unable to upload utf-8 filenames as attachments.
14 Jun 2015 (1.00)	Released with Foswiki 2.0. Foswikitask:Item13378: Foswikitask:Item13405: Update for UNICODE core Foswikitask:Item13228: Fix JSON operation with ApacheRequest2 Foswikitask:Item13125: CGI updates Foswikitask:Item13225: Fix compatibility with Apache 2.4 Foswikitask:Item13052: Documentation improvements for APREQ2_ReadLimit Foswikitask:Item9139: Improve compatibility.
03 Sep 2009 (0.9.2)	Improved documentation regarding module apreq
12 Apr 2009 (0.9.1)	Improved documentation
12 Jan 2009 (0.9.0)	Initial Release