mod_perl 2.0 renaming


This document discusses the effects of the decision to rename parts of the mod_perl API.


During a sequence of release candidates leading up to the official release of mod_perl 2, in late December, 2004 there was considerable discussion regarding the choice of namespaces for the 2.0 API. The main concern expressed was that some of the Apache::* modules used in mod_perl 2 had the same names as those in mod_perl 1. After a lively and, at times, heated debate, a proposal was made to rename parts of the mod_perl 2 API - see the thread at This proposal was subsequently voted on and then adopted.


The main changes involved in this renaming are as follows.

  • Rename all Apache::* modules to Apache2::*, save for the following exceptions:

    • The Apache::Test* modules in the Apache-Test distribution are unaffected by this rename.

    • Constants under the Apache::* namespace, such as Apache::OK, are now called as Apache2::Const::* (for example, Apache2::Const::OK).

    • Constants under the APR::* namespace, such as APR::SUCCESS, are now called as APR::Const::* (for example, APR::Const::SUCCESS).

  • Apache->request() has been renamed to Apache2::RequestUtil->request().

  • Apache->server() has been renamed to Apache2::ServerUtil->server().

  • Rename to

  • Discontinue the practice of installing mod_perl in a relative Apache2 subdirectory, so that the use of to adjust @INC is no longer needed.

Concurrent with these changes, a decision was also made to refuse to install mod_perl 2 in the same Perl tree as any installed mod_perl 2 package of version prior to 1.999_22.


The mod_perl developers did not take lightly the effects of changing the API at such a late stage in the development cycle. For most users the change to the new API should be relatively straightforward:

  • Before installing mod_perl 2, either remove an earlier mod_perl 2 installation (prior to 1.999022), or else choose to install the new version in a different area. To remove enough of a prior installation of mod_perl 2 in order to satisfy this requirement, one can do, on Unix,

      % find /usr/lib/perl5 -name 'Apache2*' -exec rm -rf {} \;

    where /usr/lib/perl5 is the top-level root of your Perl tree. Note that this will also remove any 3rd party Apache modules installed under an Apache2 subdirectory. In many situations you would want to do this, as such modules will need porting to the new API. However, if there are modules under this location that you want to keep, you can use

      % find /usr/lib/perl5 -name 'Apache2*' -exec ls -lR {} \;

    to list the files under this tree.

    For Win32 ppm users, the command

      ppm> remove mod_perl

    within the ppm shell will remove an installed mod_perl ppm package.

  • If building mod_perl 2 from source, the Makefile.PL argument of MP_INST_APACHE2 is no longer supported.

  • Replace the use of

        use Apache::SomeCoreModule;

    in a script or module by

        use Apache2::SomeCoreModule;

    Similarly, an Apache directive

        PerlModule Apache::SomeCoreModule

    in an httpd.conf file should be replaced by

        PerlModule Apache2::SomeCoreModule

    and mod_perl should be replaced by mod_perl2 in the same places.

    Note that "core modules" are defined as those that ship with the mod_perl 2 distribution. Other CPAN modules in the Apache:: namespace may not follow the same conventions.

  • Replace the use of constants Apache::* by Apache2::Const::* and APR::* by APR::Const::*.

  • Remove any occurrences of

        use Apache2;

    in a script or module, as well as

        PerlModule Apache2

    in an Apache configuration file.

  • In a script or module, replace Apache->request() by Apache2::RequestUtil->request() and Apache->server() by Apache2::ServerUtil->server().

  • If using you will need to upgrade to version 3.11 - versions 3.10 and older contain bugs and versions 3.07 and older do not support support the new mod_perl API. you can get from

Beginning with mod_perl-1.999_22, an environment variable $ENV{MOD_PERL_API_VERSION} has been added to specify which mod_perl version is being used.

See Also

The directions for installing mod_perl 2.0 . Help is also available through the archives of and subscribing to the mod_perl mailing list.


The mod_perl development team and numerous contributors.