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<ul id="index">
<li><a href="#NAME">NAME</a></li>
<li><a href="#Synopsis">Synopsis</a></li>
<li><a href="#Description">Description</a></li>
<li><a href="#API">API</a>
<ul>
<li><a href="#server">server</a></li>
</ul>
</li>
<li><a href="#PerlConfig-and-PerlConfig">@PerlConfig and $PerlConfig</a></li>
<li><a href="#Configuration-Variables">Configuration Variables</a>
<ul>
<li><a href="#Apache2::PerlSections::Save">$Apache2::PerlSections::Save</a></li>
</ul>
</li>
<li><a href="#PerlSections-Dumping">PerlSections Dumping</a>
<ul>
<li><a href="#Apache2::PerlSections-dump">Apache2::PerlSections->dump</a></li>
<li><a href="#Apache2::PerlSections-store">Apache2::PerlSections->store</a></li>
</ul>
</li>
<li><a href="#Advanced-API">Advanced API</a></li>
<li><a href="#Verifying-Perl-Sections">Verifying <Perl> Sections</a></li>
<li><a href="#Bugs">Bugs</a>
<ul>
<li><a href="#Perl-directive-missing-closing"><Perl> directive missing closing '>'</a></li>
<li><a href="#Perl-...-was-not-closed"><Perl>[...]> was not closed.</a></li>
</ul>
</li>
<li><a href="#See-Also">See Also</a></li>
<li><a href="#Copyright">Copyright</a></li>
<li><a href="#Authors">Authors</a></li>
</ul>
<h1 id="NAME">NAME</h1>
<p>Apache2::PerlSections - write Apache configuration files in Perl</p>
<h1 id="Synopsis">Synopsis</h1>
<pre><code> <Perl>
@PerlModule = qw(Mail::Send Devel::Peek);
#run the server as whoever starts it
$User = getpwuid(>) || >;
$Group = getgrgid()) || );
$ServerAdmin = $User;
</Perl></code></pre>
<h1 id="Description">Description</h1>
<p>With <code><Perl></code>...<code></Perl></code> sections, it is possible to configure your server entirely in Perl.</p>
<p><code><Perl></code> sections can contain <i>any</i> 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.</p>
<p>Block sections such as <code><Location></code>..<code></Location></code> are represented in a <code>%Location</code> hash, e.g.:</p>
<pre><code> <Perl>
$Location{"/~dougm/"} = {
AuthUserFile => '/tmp/htpasswd',
AuthType => 'Basic',
AuthName => 'test',
DirectoryIndex => [qw(index.html index.htm)],
Limit => {
"GET POST" => {
require => 'user dougm',
}
},
};
</Perl></code></pre>
<p>If an Apache directive can take two or three arguments you may push strings (the lowest number of arguments will be shifted off the <code>@list</code>) or use an array reference to handle any number greater than the minimum for that directive:</p>
<pre><code> push @Redirect, "/foo", "http://www.foo.com/";
push @Redirect, "/imdb", "http://www.imdb.com/";
push @Redirect, [qw(temp "/here" "http://www.there.com")];</code></pre>
<p>Other section counterparts include <code>%VirtualHost</code>, <code>%Directory</code> and <code>%Files</code>.</p>
<p>To pass all environment variables to the children with a single configuration directive, rather than listing each one via <code>PassEnv</code> or <code>PerlPassEnv</code>, a <code><Perl></code> section could read in a file and:</p>
<pre><code> push @PerlPassEnv, [$key => $val];</code></pre>
<p>or</p>
<pre><code> Apache2->httpd_conf("PerlPassEnv $key $val");</code></pre>
<p>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</i> and <i>eg/perl_sections.txt</i> in the mod_perl distribution for more examples.</p>
<p>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</i> the same (e.g. the <code>ServerName</code> directive) it's not quite that simple.</p>
<p><code><Perl></code> 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 <code>ServerName</code> directive you might have this <code><Perl></code> section:</p>
<pre><code> <Perl>
$ServerName = `hostname`;
</Perl></code></pre>
<p>For example if you want to allow personal directories on all machines except the ones whose names start with <i>secure</i>:</p>
<pre><code> <Perl>
$ServerName = `hostname`;
if ($ServerName !~ /^secure/) {
$UserDir = "public.html";
}
else {
$UserDir = "DISABLED";
}
</Perl></code></pre>
<h1 id="API">API</h1>
<p><code>Apache2::PerlSections</code> provides the following functions and/or methods:</p>
<h2 id="server"><code>server</code></h2>
<p>Get the current server's object for the <Perl> section</p>
<pre><code> <Perl>
$s = Apache2::PerlSections->server();
</Perl></code></pre>
<dl>
<dt id="obj:-Apache2::PerlSections-class-name">obj: <code>Apache2::PerlSections</code> (class name)</dt>
<dd>
</dd>
<dt id="ret:-s-Apache2::ServerRec-object">ret: <code>$s</code> ( <code><a>Apache2::ServerRec object</a></code> )</dt>
<dd>
</dd>
<dt id="since:-2.0.03">since: 2.0.03</dt>
<dd>
</dd>
</dl>
<h1 id="PerlConfig-and-PerlConfig"><code>@PerlConfig</code> and <code>$PerlConfig</code></h1>
<p>This array and scalar can be used to introduce literal configuration into the apache configuration. For example:</p>
<pre><code> push @PerlConfig, 'Alias /foo /bar';</code></pre>
<p>Or: $PerlConfig .= "Alias /foo /bar\n";</p>
<p>See also <code><a>$r->add_config</a></code></p>
<h1 id="Configuration-Variables">Configuration Variables</h1>
<p>There are a few variables that can be set to change the default behaviour of <code><Perl></code> sections.</p>
<h2 id="Apache2::PerlSections::Save"><code>$Apache2::PerlSections::Save</code></h2>
<p>Each <code><Perl></code> section is evaluated in its unique namespace, by default residing in a sub-namespace of <code>Apache2::ReadConfig::</code>, therefore any local variables will end up in that namespace. For example if a <code><Perl></code> section happened to be in file <i>/tmp/httpd.conf</i> starting on line 20, the namespace: <code>Apache2::ReadConfig::tmp::httpd_conf::line_20</code> will be used. Now if it had:</p>
<pre><code> <Perl>
$foo = 5;
my $bar = 6;
$My::tar = 7;
</Perl></code></pre>
<p>The local global variable <code>$foo</code> becomes <code>$Apache2::ReadConfig::tmp::httpd_conf::line_20::foo</code>, the other variable remain where they are.</p>
<p>By default, the namespace in which <code><Perl></code> sections are evaluated is cleared after each block closes. In our example nuking <code>$Apache2::ReadConfig::tmp::httpd_conf::line_20::foo</code>, leaving the rest untouched.</p>
<p>By setting <code>$Apache2::PerlSections::Save</code> to a true value, the content of those namespaces will be preserved and will be available for inspection by <code><a>Apache2::Status</a></code> and <code><a href="#C_Apache2__PerlSections_E_gt_dump_">Apache2::PerlSections->dump</a></code> In our example <code>$Apache2::ReadConfig::tmp::httpd_conf::line_20::foo</code> will still be accessible from other perl code, after the <code><Perl></code> section was parsed.</p>
<h1 id="PerlSections-Dumping">PerlSections Dumping</h1>
<h2 id="Apache2::PerlSections-dump"><code>Apache2::PerlSections->dump</code></h2>
<p>This method will dump out all the configuration variables mod_perl will be feeding to the apache config gears. The output is suitable to read back in via <code>eval</code>.</p>
<pre><code> my $dump = Apache2::PerlSections->dump;</code></pre>
<dl>
<dt id="ret:-dump-string-undef">ret: <code>$dump</code> ( string / <code>undef</code> )</dt>
<dd>
<p>A string dump of all the Perl code encountered in <Perl> blocks, suitable to be read back via <code>eval</code></p>
</dd>
</dl>
<p>For example:</p>
<pre><code> <Perl>
$Apache2::PerlSections::Save = 1;
$Listen = 8529;
$Location{"/perl"} = {
SetHandler => "perl-script",
PerlHandler => "ModPerl::Registry",
Options => "ExecCGI",
};
@DirectoryIndex = qw(index.htm index.html);
$VirtualHost{"www.foo.com"} = {
DocumentRoot => "/tmp/docs",
ErrorLog => "/dev/null",
Location => {
"/" => {
Allowoverride => 'All',
Order => 'deny,allow',
Deny => 'from all',
Allow => 'from foo.com',
},
},
};
</Perl>
<Perl>
print Apache2::PerlSections->dump;
</Perl></code></pre>
<p>This will print something like this:</p>
<pre><code> $Listen = 8529;
@DirectoryIndex = (
'index.htm',
'index.html'
);
$Location{'/perl'} = (
PerlHandler => 'Apache2::Registry',
SetHandler => 'perl-script',
Options => 'ExecCGI'
);
$VirtualHost{'www.foo.com'} = (
Location => {
'/' => {
Deny => 'from all',
Order => 'deny,allow',
Allow => 'from foo.com',
Allowoverride => 'All'
}
},
DocumentRoot => '/tmp/docs',
ErrorLog => '/dev/null'
);
1;
__END__</code></pre>
<p>It is important to put the call to <code>dump</code> in it's own <code><Perl></code> section, otherwise the content of the current <code><Perl></code> section will not be dumped.</p>
<h2 id="Apache2::PerlSections-store"><code>Apache2::PerlSections->store</code></h2>
<p>This method will call the <code>dump</code> method, writing the output to a file, suitable to be pulled in via <code>require</code> or <code>do</code>.</p>
<pre><code> Apache2::PerlSections->store($filename);</code></pre>
<dl>
<dt id="arg1:-filename-string">arg1: <code>$filename</code> (string)</dt>
<dd>
<p>The filename to save the dump output to</p>
</dd>
<dt id="ret:-no-return-value">ret: no return value</dt>
<dd>
</dd>
</dl>
<h1 id="Advanced-API">Advanced API</h1>
<p>mod_perl 2.0 now introduces the same general concept of handlers to <code><Perl></code> sections. Apache2::PerlSections simply being the default handler for them.</p>
<p>To specify a different handler for a given perl section, an extra handler argument must be given to the section:</p>
<pre><code> <Perl handler="My::PerlSection::Handler" somearg="test1">
$foo = 1;
$bar = 2;
</Perl></code></pre>
<p>And in My/PerlSection/Handler.pm:</p>
<pre><code> sub My::Handler::handler : handler {
my ($self, $parms, $args) = @_;
#do your thing!
}</code></pre>
<p>So, when that given <code><Perl></code> block in encountered, the code within will first be evaluated, then the handler routine will be invoked with 3 arguments:</p>
<dl>
<dt id="arg1:-self">arg1: <code>$self</code></dt>
<dd>
<p>self-explanatory</p>
</dd>
<dt id="arg2:-parms-Apache2::CmdParms">arg2: <code>$parms</code> ( <code><a>Apache2::CmdParms</a></code> )</dt>
<dd>
<p><code>$parms</code> is specific for the current Container, for example, you might want to call <code>$parms->server()</code> to get the current server.</p>
</dd>
<dt id="arg3:-args-APR::Table-object">arg3: <code>$args</code> ( <code><a>APR::Table object</a></code>)</dt>
<dd>
<p>the table object of the section arguments. The 2 guaranteed ones will be:</p>
<pre><code> $args->{'handler'} = 'My::PerlSection::Handler';
$args->{'package'} = 'Apache2::ReadConfig';</code></pre>
<p>Other <code>name="value"</code> pairs given on the <code><Perl></code> line will also be included.</p>
</dd>
</dl>
<p>At this point, it's up to the handler routing to inspect the namespace of the <code>$args</code>->{'package'} and chooses what to do.</p>
<p>The most likely thing to do is to feed configuration data back into apache. To do that, use Apache2::Server->add_config("directive"), for example:</p>
<pre><code> $parms->server->add_config("Alias /foo /bar");</code></pre>
<p>Would create a new alias. The source code of <code>Apache2::PerlSections</code> is a good place to look for a practical example.</p>
<h1 id="Verifying-Perl-Sections">Verifying <code><Perl></code> Sections</h1>
<p>If the <code><Perl></code> sections include no code requiring a running mod_perl, it is possible to check those from the command line. But the following trick should be used:</p>
<pre><code> # file: httpd.conf
<Perl>
#!perl
# ... code here ...
__END__
</Perl></code></pre>
<p>Now you can run:</p>
<pre><code> % perl -c httpd.conf</code></pre>
<h1 id="Bugs">Bugs</h1>
<h2 id="Perl-directive-missing-closing"><Perl> directive missing closing '>'</h2>
<p>httpd-2.0.47 had a bug in the configuration parser which caused the startup failure with the following error:</p>
<pre><code> Starting httpd:
Syntax error on line ... of /etc/httpd/conf/httpd.conf:
<Perl> directive missing closing '>' [FAILED]</code></pre>
<p>This has been fixed in httpd-2.0.48. If you can't upgrade to this or a higher version, please add a space before the closing '>' of the opening tag as a workaround. So if you had:</p>
<pre><code> <Perl>
# some code
</Perl></code></pre>
<p>change it to be:</p>
<pre><code> <Perl >
# some code
</Perl></code></pre>
<h2 id="Perl-...-was-not-closed"><Perl>[...]> was not closed.</h2>
<p>On encountering a one-line <Perl> block, httpd's configuration parser will cause a startup failure with an error similar to this one:</p>
<pre><code> Starting httpd:
Syntax error on line ... of /etc/httpd/conf/httpd.conf:
<Perl>use> was not closed.</code></pre>
<p>If you have written a simple one-line <Perl> section like this one :</p>
<pre><code> <Perl>use Apache::DBI;</Perl></code></pre>
<p>change it to be:</p>
<pre><code> <Perl>
use Apache::DBI;
</Perl></code></pre>
<p>This is caused by a limitation of httpd's configuration parser and is not likely to be changed to allow one-line block like the example above. Use multi-line blocks instead.</p>
<h1 id="See-Also">See Also</h1>
<p><a>mod_perl 2.0 documentation</a>.</p>
<h1 id="Copyright">Copyright</h1>
<p>mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0.</p>
<h1 id="Authors">Authors</h1>
<p><a>The mod_perl development team and numerous contributors</a>.</p>
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