perlsections.pm

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# Copyright 2003-2005 The Apache Software Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
package Apache2::PerlSections;

use strict;
use warnings FATAL => 'all';

our $VERSION = '2.00';

use Apache2::CmdParms ();
use Apache2::Directive ();
use APR::Table ();
use Apache2::ServerRec ();
use Apache2::ServerUtil ();
use Apache2::Const -compile => qw(OK);

use constant SPECIAL_NAME => 'PerlConfig';
use constant SPECIAL_PACKAGE => 'Apache2::ReadConfig';

sub new {
    my ($package, @args) = @_;
    return bless { @args }, ref($package) || $package;
}

sub parms      { return shift->{'parms'} }
sub directives { return shift->{'directives'} ||= [] }
sub package    { return shift->{'args'}->{'package'} }

my @saved;
sub save       { return $Apache2::PerlSections::Save }
sub saved      { return @saved }

sub handler : method {
    my ($self, $parms, $args) = @_;

    unless (ref $self) {
        $self = $self->new('parms' => $parms, 'args' => $args);
    }

    if ($self->save) {
        push @saved, $self->package;
    }

    my $special = $self->SPECIAL_NAME;

    for my $entry ($self->symdump()) {
        if ($entry->[0] !~ /$special/) {
            $self->dump_any(@$entry);
        }
    }

    {
        no strict 'refs';
        foreach my $package ($self->package) {
            $self->dump_special(${"${package}::$special"},
              @{"${package}::$special"} );
        }
    }

    $self->post_config();

    Apache2::Const::OK;
}

sub symdump {
    my ($self) = @_;

    unless ($self->{symbols}) {
        no strict;

        $self->{symbols} = [];

        #XXX: Here would be a good place to warn about NOT using 
        #     Apache2::ReadConfig:: directly in <Perl> sections
        foreach my $pack ($self->package, $self->SPECIAL_PACKAGE) {
            #XXX: Shamelessly borrowed from Devel::Symdump;
            while (my ($key, $val) = each(%{ *{"$pack\::"} })) {
                #We don't want to pick up stashes...
                next if ($key =~ /::$/);
                local (*ENTRY) = $val;
                if (defined $val && defined *ENTRY{SCALAR}) {
                    push @{$self->{symbols}}, [$key, $ENTRY];
                }
                if (defined $val && defined *ENTRY{ARRAY}) {
                    push @{$self->{symbols}}, [$key, \@ENTRY];
                }
                if (defined $val && defined *ENTRY{HASH} && $key !~ /::/) {
                    push @{$self->{symbols}}, [$key, \%ENTRY];
                }
            }
        }
    }

    return @{$self->{symbols}};
}

sub dump_special {
    my ($self, @data) = @_;
    $self->add_config(@data);
}

sub dump_any {
    my ($self, $name, $entry) = @_;
    my $type = ref $entry;

    if ($type eq 'ARRAY') {
        $self->dump_array($name, $entry);
    }
    elsif ($type eq 'HASH') {
        $self->dump_hash($name, $entry);
    }
    else {
        $self->dump_entry($name, $entry);
    }
}

sub dump_hash {
    my ($self, $name, $hash) = @_;

    for my $entry (sort keys %{ $hash || {} }) {
        my $item = $hash->{$entry};
        my $type = ref($item);

        if ($type eq 'HASH') {
            $self->dump_section($name, $entry, $item);
        }
        elsif ($type eq 'ARRAY') {
            for my $e (@$item) {
                $self->dump_section($name, $entry, $e);
            }
        }
    }
}

sub dump_section {
    my ($self, $name, $loc, $hash) = @_;

    $self->add_config("<$name $loc>\n");

    for my $entry (sort keys %{ $hash || {} }) {
        $self->dump_entry($entry, $hash->{$entry});
    }

    $self->add_config("</$name>\n");
}

sub dump_array {
    my ($self, $name, $entries) = @_;

    for my $entry (@$entries) {
        $self->dump_entry($name, $entry);
    }
}

sub dump_entry {
    my ($self, $name, $entry) = @_;
    my $type = ref $entry;

    if ($type eq 'SCALAR') {
        $self->add_config("$name $$entry\n");
    }
    elsif ($type eq 'ARRAY') {
        if (grep {ref} @$entry) {
            $self->dump_entry($name, $_) for @$entry;
        }
        else {
            $self->add_config("$name @$entry\n");
        }
    }
    elsif ($type eq 'HASH') {
        $self->dump_hash($name, $entry);
    }
    elsif ($type) {
        #XXX: Could do $type->can('httpd_config') here on objects ???
        die "Unknown type '$type' for directive $name";
    }
    elsif (defined $entry) {
        $self->add_config("$name $entry\n");
    }
}

sub add_config {
    my ($self, $config) = @_;
    return unless defined $config;
    chomp($config);
    push @{ $self->directives }, $config;
}

sub post_config {
    my ($self) = @_;
    my $errmsg = $self->parms->add_config($self->directives);
    die $errmsg if $errmsg;
}

sub dump {
    my $class = shift;
    require Apache2::PerlSections::Dump;
    return Apache2::PerlSections::Dump->dump(@_);
}

sub store {
    my $class = shift;
    require Apache2::PerlSections::Dump;
    return Apache2::PerlSections::Dump->store(@_);
}

1;
__END__

=head1 NAME

Apache2::PerlSections - write Apache configuration files in Perl





=head1 Synopsis

  <Perl>
  @PerlModule = qw(Mail::Send Devel::Peek);
  
  #run the server as whoever starts it
  $User  = getpwuid(>) || >;
  $Group = getgrgid()) || );
  
  $ServerAdmin = $User;
  
  </Perl>






=head1 Description

With C<E<lt>PerlE<gt>>...C<E<lt>/PerlE<gt>> sections, it is possible
to configure your server entirely in Perl.

C<E<lt>PerlE<gt>> sections can contain I<any> and as much Perl code as
you wish. These sections are compiled into a special package whose
symbol table mod_perl can then walk and grind the names and values of
Perl variables/structures through the Apache core configuration gears.

Block sections such as C<E<lt>LocationE<gt>>..C<E<lt>/LocationE<gt>>
are represented in a C<%Location> hash, e.g.:

  <Perl>
  $Location{"/~dougm/"} = {
    AuthUserFile   => '/tmp/htpasswd',
    AuthType       => 'Basic',
    AuthName       => 'test',
    DirectoryIndex => [qw(index.html index.htm)],
    Limit          => {
        "GET POST"    => {
            require => 'user dougm',
        }
    },
  };
  </Perl>

If an Apache directive can take two or three arguments you may push
strings (the lowest number of arguments will be shifted off the
C<@list>) or use an array reference to handle any number greater than
the minimum for that directive:

  push @Redirect, "/foo", "http://www.foo.com/";
  
  push @Redirect, "/imdb", "http://www.imdb.com/";
  
  push @Redirect, [qw(temp "/here" "http://www.there.com")];

Other section counterparts include C<%VirtualHost>, C<%Directory> and
C<%Files>.

To pass all environment variables to the children with a single
configuration directive, rather than listing each one via C<PassEnv>
or C<PerlPassEnv>, a C<E<lt>PerlE<gt>> section could read in a file and:

  push @PerlPassEnv, [$key => $val];

or

  Apache2->httpd_conf("PerlPassEnv $key $val");

These are somewhat simple examples, but they should give you the basic
idea. You can mix in any Perl code you desire. See I<eg/httpd.conf.pl>
and I<eg/perl_sections.txt> in the mod_perl distribution for more
examples.

Assume that you have a cluster of machines with similar configurations
and only small distinctions between them: ideally you would want to
maintain a single configuration file, but because the configurations
aren't I<exactly> the same (e.g. the C<ServerName> directive) it's not
quite that simple.

C<E<lt>PerlE<gt>> sections come to rescue. Now you have a single
configuration file and the full power of Perl to tweak the local
configuration. For example to solve the problem of the C<ServerName>
directive you might have this C<E<lt>PerlE<gt>> section:

  <Perl>
  $ServerName = `hostname`;
  </Perl>

For example if you want to allow personal directories on all machines
except the ones whose names start with I<secure>:

  <Perl>
  $ServerName = `hostname`;
  if ($ServerName !~ /^secure/) {
      $UserDir = "public.html";
  }
  else {
      $UserDir = "DISABLED";
  }
  </Perl>






=head1 C<@PerlConfig> and C<$PerlConfig>

This array and scalar can be used to introduce literal configuration
into the apache configuration. For example:

  push @PerlConfig, 'Alias /foo /bar';

Or: