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apache2::perlsections(3) [osx man page]


Apache2::PerlSections - write Apache configuration files in Perl Synopsis <Perl> @PerlModule = qw(Mail::Send Devel::Peek); #run the server as whoever starts it $User = getpwuid(>) || >; $Group = getgrgid()) || ); $ServerAdmin = $User; </Perl> Description With "<Perl>"..."</Perl>" sections, it is possible to configure your server entirely in Perl. "<Perl>" sections can contain 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 "<Location>".."</Location>" are represented in a %Location hash, e.g.: <Perl> $Location{"/~dougm/"} = { AuthUserFile => '/tmp/htpasswd', AuthType => 'Basic', AuthName => 'test', DirectoryIndex => [qw(index.html index.htm)], Limit => { "GET POST" => { require => 'user dougm', } }, }; </Perl> If an Apache directive can take two or three arguments you may push strings (the lowest number of arguments will be shifted off the @list) or use an array reference to handle any number greater than the minimum for that directive: push @Redirect, "/foo", ""; push @Redirect, "/imdb", ""; push @Redirect, [qw(temp "/here" "")]; Other section counterparts include %VirtualHost, %Directory and %Files. To pass all environment variables to the children with a single configuration directive, rather than listing each one via "PassEnv" or "PerlPassEnv", a "<Perl>" section could read in a file and: push @PerlPassEnv, [$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 eg/ and 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 exactly the same (e.g. the "ServerName" directive) it's not quite that simple. "<Perl>" 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 "ServerName" directive you might have this "<Perl>" section: <Perl> $ServerName = `hostname`; </Perl> For example if you want to allow personal directories on all machines except the ones whose names start with secure: <Perl> $ServerName = `hostname`; if ($ServerName !~ /^secure/) { $UserDir = "public.html"; } else { $UserDir = "DISABLED"; } </Perl> API
"Apache2::PerlSections" provides the following functions and/or methods: "server" Get the current server's object for the <Perl> section <Perl> $s = Apache2::PerlSections->server(); </Perl> obj: "Apache2::PerlSections" (class name) ret: $s ( "Apache2::ServerRec object" ) since: 2.0.03 @PerlConfig and $PerlConfig This array and scalar can be used to introduce literal configuration into the apache configuration. For example: push @PerlConfig, 'Alias /foo /bar'; Or: $PerlConfig .= "Alias /foo /bar "; See also "$r->add_config" Configuration Variables There are a few variables that can be set to change the default behaviour of "<Perl>" sections. $Apache2::PerlSections::Save Each "<Perl>" section is evaluated in its unique namespace, by default residing in a sub-namespace of "Apache2::ReadConfig::", therefore any local variables will end up in that namespace. For example if a "<Perl>" section happened to be in file /tmp/httpd.conf starting on line 20, the namespace: "Apache2::ReadConfig::tmp::httpd_conf::line_20" will be used. Now if it had: <Perl> $foo = 5; my $bar = 6; $My::tar = 7; </Perl> The local global variable $foo becomes $Apache2::ReadConfig::tmp::httpd_conf::line_20::foo, the other variable remain where they are. By default, the namespace in which "<Perl>" sections are evaluated is cleared after each block closes. In our example nuking $Apache2::ReadConfig::tmp::httpd_conf::line_20::foo, leaving the rest untouched. By setting $Apache2::PerlSections::Save to a true value, the content of those namespaces will be preserved and will be available for inspection by "Apache2::Status" and "Apache2::PerlSections->dump" In our example $Apache2::ReadConfig::tmp::httpd_conf::line_20::foo will still be accessible from other perl code, after the "<Perl>" section was parsed. PerlSections Dumping "Apache2::PerlSections->dump" 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 "eval". my $dump = Apache2::PerlSections->dump; ret: $dump ( string / "undef" ) A string dump of all the Perl code encountered in <Perl> blocks, suitable to be read back via "eval" For example: <Perl> $Apache2::PerlSections::Save = 1; $Listen = 8529; $Location{"/perl"} = { SetHandler => "perl-script", PerlHandler => "ModPerl::Registry", Options => "ExecCGI", }; @DirectoryIndex = qw(index.htm index.html); $VirtualHost{""} = { DocumentRoot => "/tmp/docs", ErrorLog => "/dev/null", Location => { "/" => { Allowoverride => 'All', Order => 'deny,allow', Deny => 'from all', Allow => 'from', }, }, }; </Perl> <Perl> print Apache2::PerlSections->dump; </Perl> This will print something like this: $Listen = 8529; @DirectoryIndex = ( 'index.htm', 'index.html' ); $Location{'/perl'} = ( PerlHandler => 'Apache2::Registry', SetHandler => 'perl-script', Options => 'ExecCGI' ); $VirtualHost{''} = ( Location => { '/' => { Deny => 'from all', Order => 'deny,allow', Allow => 'from', Allowoverride => 'All' } }, DocumentRoot => '/tmp/docs', ErrorLog => '/dev/null' ); 1; __END__ It is important to put the call to "dump" in it's own "<Perl>" section, otherwise the content of the current "<Perl>" section will not be dumped. "Apache2::PerlSections->store" This method will call the "dump" method, writing the output to a file, suitable to be pulled in via "require" or "do". Apache2::PerlSections->store($filename); arg1: $filename (string) The filename to save the dump output to ret: no return value Advanced API mod_perl 2.0 now introduces the same general concept of handlers to "<Perl>" sections. Apache2::PerlSections simply being the default handler for them. To specify a different handler for a given perl section, an extra handler argument must be given to the section: <Perl handler="My::PerlSection::Handler" somearg="test1"> $foo = 1; $bar = 2; </Perl> And in My/PerlSection/ sub My::Handler::handler : handler { my ($self, $parms, $args) = @_; #do your thing! } So, when that given "<Perl>" block in encountered, the code within will first be evaluated, then the handler routine will be invoked with 3 arguments: arg1: $self self-explanatory arg2: $parms ( "Apache2::CmdParms" ) $parms is specific for the current Container, for example, you might want to call "$parms->server()" to get the current server. arg3: $args ( "APR::Table object") the table object of the section arguments. The 2 guaranteed ones will be: $args->{'handler'} = 'My::PerlSection::Handler'; $args->{'package'} = 'Apache2::ReadConfig'; Other "name="value"" pairs given on the "<Perl>" line will also be included. At this point, it's up to the handler routing to inspect the namespace of the $args->{'package'} and chooses what to do. 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: $parms->server->add_config("Alias /foo /bar"); Would create a new alias. The source code of "Apache2::PerlSections" is a good place to look for a practical example. Verifying ";<Perl>" Sections If the "<Perl>" 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: # file: httpd.conf <Perl> #!perl # ... code here ... __END__ </Perl> Now you can run: % perl -c httpd.conf Bugs <Perl> directive missing closing '>' httpd-2.0.47 had a bug in the configuration parser which caused the startup failure with the following error: Starting httpd: Syntax error on line ... of /etc/httpd/conf/httpd.conf: <Perl> directive missing closing '>' [FAILED] 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: <Perl> # some code </Perl> change it to be: <Perl > # some code </Perl> <Perl>[...]> was not closed. On encountering a one-line <Perl> block, httpd's configuration parser will cause a startup failure with an error similar to this one: Starting httpd: Syntax error on line ... of /etc/httpd/conf/httpd.conf: <Perl>use> was not closed. If you have written a simple one-line <Perl> section like this one : <Perl>use Apache::DBI;</Perl> change it to be: <Perl> use Apache::DBI; </Perl> 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. See Also mod_perl 2.0 documentation. Copyright mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0. Authors The mod_perl development team and numerous contributors. perl v5.16.2 20apache_mod_perl-108~358::mod_perl-2.0.7::docs::api::Apache2::PerlSections(3)
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