mod_perl 2.0 Server Configuration
This chapter provides an in-depth mod_perl 2.0 configuration details.
Similar to mod_perl 1.0, in order to use mod_perl 2.0 a few configuration settings should be added to httpd.conf. They are quite similar to 1.0 settings but some directives were renamed and new directives were added.
To enable mod_perl built as DSO add to httpd.conf:
LoadModule perl_module modules/mod_perl.so
This setting specifies the location of the mod_perl module relative to the ServerRoot setting, therefore you should put it somewhere after ServerRoot is specified.
ServerRoot
If mod_perl has been statically linked it's automatically enabled.
For Win32 specific details, see the documentation on Win32 configuration.
Remember that you can't use mod_perl until you have configured Apache to use it. You need to configure Registry scripts or custom handlers.
In order to prevent from inadvertently loading mod_perl 1.0 modules mod_perl 2.0 Perl modules are installed into dedicated directories under Apache2/. The Apache2 module prepends the locations of the mod_perl 2.0 libraries to @INC, which are the same as the core @INC, but with Apache2/ appended. This module has to be loaded just after mod_perl has been enabled. This can be accomplished with:
Apache2
@INC
use Apache2 ();
in the startup file. Only if you don't use a startup file you can add:
PerlModule Apache2
to httpd.conf, due to the order the PerlRequire and PerlModule directives are processed.
PerlRequire
PerlModule
As explained in the Server Life Cycle chapter, normally Apache runs the server configuration phase, followed by PerlOpenLogsHandler and PerlPostConfigHandler phases, then immediately restarts itself. Therefore everything running at the server startup is executed twice. During the restart, Perl is completely destroyed and started again.
PerlOpenLogsHandler
PerlPostConfigHandler
If Apache is started as 'httpd -t' (equivalent to 'apachectl configtest') or as 'httpd -S', it will run only the configuration phase and exit. mod_perl 2.0 postpones the startup of Perl until after the configuration phase is over, to allow the usage of the PerlSwitches directive, which can't be used after Perl is started. mod_perl starts Perl and runs any registered PerlRequire and PerlModule entries as the very first thing during the PerlOpenLogsHandler phase, which is not invoked during the 'apachectl configtest' execution.
'httpd -t'
'apachectl configtest'
'httpd -S'
PerlSwitches
There are two cases when mod_perl 2.0 is forced to start early (during the configuration phase). First, is when PerlLoadModule is used and second is when a <Perl> section is encountered, both requiring a running Perl, and therefore triggering an early server startup.
PerlLoadModule
<Perl> section
Therefore at the moment, if you want to trigger an early Perl startup, just add an empty <Perl> section in httpd.conf:
<Perl> # trigger an early Perl startup </Perl>
right after loading the mod_perl module, if you are using DSO, or just before your mod_perl configuration section, if you're using a static mod_perl build.
A startup file with Perl code to be executed at the server startup can be loaded using PerlRequire. For example:
PerlRequire /home/httpd/perl/lib/startup.pl
It's used to adjust Perl modules search paths in @INC, pre-load commonly used modules, pre-compile constants, etc. Here is a typical startup.pl for mod_perl 2.0:
file:startup.pl --------------- use Apache2 (); use lib qw(/home/httpd/perl); # enable if the mod_perl 1.0 compatibility is needed # use Apache::compat (); # preload all mp2 modules # use ModPerl::MethodLookup; # ModPerl::MethodLookup::preload_all_modules(); use ModPerl::Util (); #for CORE::GLOBAL::exit use Apache::RequestRec (); use Apache::RequestIO (); use Apache::RequestUtil (); use Apache::ServerRec (); use Apache::ServerUtil (); use Apache::Connection (); use Apache::Log (); use APR::Table (); use ModPerl::Registry (); use Apache::Const -compile => ':common'; use APR::Const -compile => ':common'; 1;
In this file the Apache2 modules is loaded, so the 2.0 modules will be found. Afterwards @INC in adjusted to include non-standard directories with Perl modules:
use lib qw(/home/httpd/perl);
If you need to use the backwards compatibility layer load:
use Apache::compat ();
Next we preload the commonly used mod_perl 2.0 modules and precompile common constants.
Finally as usual the startup.pl file must be terminated with 1;.
1;
<Perl>
With <Perl>...</Perl> sections, it is possible to configure your server entirely in Perl.
</Perl>
Please refer to the Apache::PerlSections manpage for more information.
META: a dedicated chapter with examples?
PerlAddVar
META: to be written
The PerlLoadModule directive is similar to PerlModule, in a sense that it loads a module. The difference is that it's used to implement new Apache directives. Since those directives are needed during the configuration phase, this directive triggers an early Perl startup, as a side effect.
PerlModule Foo::Bar
is equivalent to Perl's:
require Foo::Bar;
PerlModule is used to load modules using their package names.
You can pass one or more module names as arguments to PerlModule:
PerlModule Apache::DBI CGI DBD::Mysql
Notice, that normally, the Perl startup is delayed until after the configuration phase.
See also: PerlRequire.
PerlOptions
The directive PerlOptions provides fine-grained configuration for what were compile-time only options in the first mod_perl generation. It also provides control over what class of Perl interpreter pool is used for a <VirtualHost> or location configured with <Location>, <Directory>, etc.
<VirtualHost>
<Location>
<Directory>
$r->is_perl_option_enabled($option) and $s->is_perl_option_enabled($option) can be used at run-time to check whether a certain $option has been enabled. (META: probably need to add/move this to the coding chapter)
$option
Options are enabled by prepending + and disabled with -.
+
-
The available options are:
Enable
On by default, can be used to disable mod_perl for a given VirtualHost. For example:
VirtualHost
<VirtualHost ...> PerlOptions -Enable </VirtualHost>
Clone
Share the parent Perl interpreter, but give the VirtualHost its own interpreter pool. For example should you wish to fine tune interpreter pools for a given virtual host:
<VirtualHost ...> PerlOptions +Clone PerlInterpStart 2 PerlInterpMax 2 </VirtualHost>
This might be worthwhile in the case where certain hosts have their own sets of large-ish modules, used only in each host. By tuning each host to have its own pool, that host will continue to reuse the Perl allocations in their specific modules.
When cloning a Perl interpreter, to inherit base Perl interpreter's PerlSwitches use:
<VirtualHost ...> ... PerlSwitches +inherit </VirtualHost>
Parent
Create a new parent Perl interpreter for the given VirtualHost and give it its own interpreter pool (implies the Clone option).
A common problem with mod_perl 1.0 was the shared namespace between all code within the process. Consider two developers using the same server and each wants to run a different version of a module with the same name. This example will create two parent Perl interpreters, one for each <VirtualHost>, each with its own namespace and pointing to a different paths in @INC:
META: is -Mlib portable? (problems with -Mlib on Darwin/5.6.0?)
<VirtualHost ...> ServerName dev1 PerlOptions +Parent PerlSwitches -Mlib=/home/dev1/lib/perl PerlModule Apache2 </VirtualHost> <VirtualHost ...> ServerName dev2 PerlOptions +Parent PerlSwitches -Mlib=/home/dev2/lib/perl PerlModule Apache2 </VirtualHost>
Remember that +Parent gives you a completely new Perl interpreters pool, so all your modifications to @INC and preloading of the modules should be done again. Consider using PerlOptions +Clone if you want to inherit from the parent Perl interpreter.
+Parent
Or even for a given location, for something like "dirty" cgi scripts:
<Location /cgi-bin> PerlOptions +Parent PerlInterpMaxRequests 1 PerlInterpStart 1 PerlInterpMax 1 PerlResponseHandler ModPerl::Registry </Location>
will use a fresh interpreter with its own namespace to handle each request.
Perl*Handler
Disable Perl*Handlers, all compiled-in handlers are enabled by default. The option name is derived from the Perl*Handler name, by stripping the Perl and Handler parts of the word. So PerlLogHandler becomes Log which can be used to disable PerlLogHandler:
Perl
Handler
PerlLogHandler
Log
PerlOptions -Log
Suppose one of the hosts does not want to allow users to configure PerlAuthenHandler, PerlAuthzHandler, PerlAccessHandler and <Perl> sections:
PerlAuthenHandler
PerlAuthzHandler
PerlAccessHandler
<VirtualHost ...> PerlOptions -Authen -Authz -Access -Sections </VirtualHost>
Or maybe everything but the response handler:
<VirtualHost ...> PerlOptions None +Response </VirtualHost>
AutoLoad
Resolve Perl*Handlers at startup time, which includes loading the modules from disk if not already loaded.
Perl*Handlers
In mod_perl 1.0, configured Perl*Handlers which are not a fully qualified subroutine names are resolved at request time, loading the handler module from disk if needed. In mod_perl 2.0, configured Perl*Handlers are resolved at startup time. By default, modules are not auto-loaded during startup-time resolution. It is possible to enable this feature with:
PerlOptions +Autoload
Consider this configuration:
PerlResponseHandler Apache::Magick
In this case, Apache::Magick is the package name, and the subroutine name will default to handler. If the Apache::Magick module is not already loaded, PerlOptions +Autoload will attempt to pull it in at startup time. With this option enabled you don't have to explicitly load the handler modules. For example you don't need to add:
Apache::Magick
PerlModule Apache::Magick
in our example.
GlobalRequest
Setup the global $r object for use with Apache->request.
$r
Apache->request
This setting is enabled by default during the PerlResponseHandler phase for sections configured as:
PerlResponseHandler
<Location ...> SetHandler perl-script ... </Location>
And can be disabled with:
<Location ...> SetHandler perl-script PerlOptions -GlobalRequest ... </Location>
Notice that if you need the global request object during other phases, you will need to explicitly enable it in the configuration file.
You can also set that global object from the handler code, like so:
sub handler { my $r = shift; Apache->request($r); ... }
The +GlobalRequest setting is needed for example if you use older versions of CGI.pm to process the incoming request. Starting from version 2.93, CGI.pm optionally accepts $r as an argument to new(), like so:
+GlobalRequest
CGI.pm
new()
sub handler { my $r = shift; my $q = CGI->new($r); ... }
Remember that inside registry scripts you can always get $r at the beginning of the script, since it gets wrapped inside a subroutine and accepts $r as the first and the only argument. For example:
#!/usr/bin/perl use CGI; my $r = shift; my $q = CGI->new($r); ...
of course you won't be able to run this under mod_cgi, so you may need to do:
#!/usr/bin/perl use CGI; my $q = $ENV{MOD_PERL} ? CGI->new(shift @_) : CGI->new(); ...
in order to have the script running under mod_perl and mod_cgi.
ParseHeaders
Scan output for HTTP headers, same functionality as mod_perl 1.0's PerlSendHeader, but more robust. This option is usually needs to be enabled for registry scripts which send the HTTP header with:
PerlSendHeader
print "Content-type: text/html\n\n";
MergeHandlers
Turn on merging of Perl*Handler arrays. For example with a setting:
PerlFixupHandler Apache::FixupA <Location /inside> PerlFixupHandler Apache::FixupB </Location>
a request for /inside only runs Apache::FixupB (mod_perl 1.0 behavior). But with this configuration:
Apache::FixupB
PerlFixupHandler Apache::FixupA <Location /inside> PerlOptions +MergeHandlers PerlFixupHandler Apache::FixupB </Location>
a request for /inside will run both Apache::FixupA and Apache::FixupB handlers.
Apache::FixupA
SetupEnv
Set up environment variables for each request ala mod_cgi.
When this option is enabled, mod_perl fiddles with the environment to make it appear as if the code is called under the mod_cgi handler. For example, the $ENV{QUERY_STRING} environment variable is initialized with the contents of Apache::args(), and the value returned by Apache::server_hostname() is put into $ENV{SERVER_NAME}.
$ENV{QUERY_STRING}
$ENV{SERVER_NAME}
But %ENV population is expensive. Those who have moved to the Perl Apache API no longer need this extra %ENV population, and can gain by disabling it. A code using the CGI.pm module require PerlOptions +SetupEnv because that module relies on a properly populated CGI environment table.
%ENV
PerlOptions +SetupEnv
This option is enabled by default for sections configured as:
Since this option adds an overhead to each request, if you don't need this functionality you can turn it off for a certain section:
<Location ...> SetHandler perl-script PerlOptions -SetupEnv ... </Location>
or globally:
PerlOptions -SetupEnv <Location ...> ... </Location>
and then it'll affect the whole server. It can still be enabled for sections that need this functionality.
When this option is disabled you can still read environment variables set by you. For example when you use the following configuration:
PerlOptions -SetupEnv PerlModule ModPerl::Registry <Location /perl> PerlSetEnv TEST hi SetHandler perl-script PerlResponseHandler ModPerl::Registry Options +ExecCGI </Location>
and you issue a request for this script:
setupenvoff.pl -------------- use Data::Dumper; my $r = Apache->request(); $r->content_type('text/plain'); print Dumper(\%ENV);
you should see something like this:
$VAR1 = { 'GATEWAY_INTERFACE' => 'CGI-Perl/1.1', 'MOD_PERL' => 'mod_perl/2.0.1', 'PATH' => 'bin:/usr/bin', 'TEST' => 'hi' };
Notice that we have got the value of the environment variable TEST.
PerlPassEnv
PerlRequire Foo/Bar.pm
require "Foo/Bar.pm";
PerlRequire is used to load files with Perl code.
Most commonly PerlRequire is used to load startup.pl, containing Perl code to be run at the server startup. For example:
A PerlRequire filename argument can be absolute or relative to ServerRoot or a filepath in Perl's @INC.
As with any file with Perl code that gets use()'d or require()'d, it must return a true value. To ensure that this happens don't forget to add 1; at the end of startup.pl.
use()
require()
You can pass one or more filenames as arguments to PerlRequire:
PerlRequire path1/startup.pl path2/startup.pl
Notice that normally, the Perl startup is delayed until after the configuration phase.
See also: PerlModule.
PerlSetEnv
PerlSetVar
Now you can pass any Perl's command line switches in httpd.conf using the PerlSwitches directive. For example to enable warnings and Taint checking add:
PerlSwitches -wT
As an alternative to using use lib in startup.pl to adjust @INC, now you can use the command line switch -I to do that:
use lib
-I
PerlSwitches -I/home/stas/modperl
You could also use -Mlib=/home/stas/modperl which is the exact equivalent as use lib, but it's broken on certain platforms/version (e.g. Darwin/5.6.0). use lib is removing duplicated entries, whereas -I does not.
-Mlib=/home/stas/modperl
SetHandler
mod_perl 2.0 provides two types of SetHandler handlers: modperl and perl-script. The SetHandler directive is only relevant for response phase handlers. It doesn't affect other phases.
modperl
perl-script
Configured as:
SetHandler modperl
The bare mod_perl handler type, which just calls the Perl*Handler's callback function. If you don't need the features provided by the perl-script handler, with the modperl handler, you can gain even more performance. (This handler isn't available in mod_perl 1.0.)
Unless the Perl*Handler callback, running under the modperl handler, is configured with:
or calls:
$r->subprocess_env;
in a void context with no arguments (which has the same effect as PerlOptions +SetupEnv for the handler that called it), only the following environment variables are accessible via %ENV:
MOD_PERL (always)
MOD_PERL
PATH and TZ (if you had them defined in the shell or httpd.conf)
PATH
TZ
Therefore if you don't want to add the overhead of populating %ENV, when you simply want to pass some configuration variables from httpd.conf, consider using PerlSetVar and PerlAddVar instead of PerlSetEnv and PerlPassEnv. In your code you can retrieve the values using the dir_config() method. For example if you set in httpd.conf:
dir_config()
<Location /print_env2> SetHandler modperl PerlResponseHandler Apache::VarTest PerlSetVar VarTest VarTestValue </Location>
this value can be retrieved inside Apache::VarTest::handler() with:
Apache::VarTest::handler()
$r->dir_config('VarTest');
Alternatively use the Apache core directives SetEnv and PassEnv, which always populate r->subprocess_env, but this doesn't happen until the Apache fixups phase, which could be too late for your needs.
SetEnv
PassEnv
r->subprocess_env
SetHandler perl-script
Most mod_perl handlers use the perl-script handler. Among other things it does:
PerlOptions +GlobalRequest is in effect only during the PerlResponseHandler phase unless:
PerlOptions +GlobalRequest
PerlOptions -GlobalRequest
is specified.
PerlOptions +SetupEnv is in effect unless:
PerlOptions -SetupEnv
STDIN and STDOUT get tied to the request object $r, which makes possible to read from STDIN and print directly to STDOUT via CORE::print(), instead of implicit calls like $r->puts().
STDIN
STDOUT
CORE::print()
$r->puts()
Several special global Perl variables are saved before the handler is called and restored afterwards (similar to mod_perl 1.0). This includes: %ENV, @INC, $/, STDOUT's $| and END blocks array (PL_endav).
$/
$|
END
PL_endav
Entries added to %ENV are passed on to the subprocess_env table, and are thus accessible via r->subprocess_env during the later PerlLogHandler and PerlCleanupHandler phases.
subprocess_env
PerlCleanupHandler
Let's demonstrate the differences between the modperl and the perl-script core handlers in the following example, which represents a simple mod_perl response handler which prints out the environment variables as seen by it:
file:MyApache/PrintEnv1.pm ----------------------- package MyApache::PrintEnv1; use strict; use Apache::RequestRec (); # for $r->content_type use Apache::RequestIO (); # for print use Apache::Const -compile => ':common'; sub handler { my $r = shift; $r->content_type('text/plain'); for (sort keys %ENV){ print "$_ => $ENV{$_}\n"; } return Apache::OK; } 1;
This is the required configuration:
PerlModule MyApache::PrintEnv1 <Location /print_env1> SetHandler perl-script PerlResponseHandler MyApache::PrintEnv1 </Location>
Now issue a request to http://localhost/print_env1 and you should see all the environment variables printed out.
Here is the same response handler, adjusted to work with the modperl core handler:
file:MyApache/PrintEnv2.pm ------------------------ package MyApache::PrintEnv2; use strict; use Apache::RequestRec (); # for $r->content_type use Apache::RequestIO (); # for $r->print use Apache::Const -compile => ':common'; sub handler { my $r = shift; $r->content_type('text/plain'); $r->subprocess_env; for (sort keys %ENV){ $r->print("$_ => $ENV{$_}\n"); } return Apache::OK; } 1;
The configuration now will look as:
PerlModule MyApache::PrintEnv2 <Location /print_env2> SetHandler modperl PerlResponseHandler MyApache::PrintEnv2 </Location>
MyApache::PrintEnv2 cannot use print() and therefore uses $r->print() to generate a response. Under the modperl core handler %ENV is not populated by default, therefore subprocess_env() is called in a void context. Alternatively we could configure this section to do:
MyApache::PrintEnv2
print()
$r->print()
subprocess_env()
If you issue a request to http://localhost/print_env2, you should see all the environment variables printed out as with http://localhost/print_env1.
See Server life cycle.
See PerlOpenLogsHandler.
See PerlPostConfigHandler.
PerlChildInitHandler
See PerlChildInitHandler.
PerlChildExitHandler
See PerlChildExitHandler.
See Protocol handlers.
PerlPreConnectionHandler
See PerlPreConnectionHandler.
PerlProcessConnectionHandler
See PerlProcessConnectionHandler.
mod_perl filters are described in the filter handlers tutorial, Apache::Filter and Apache::FilterRec manpages.
Apache::Filter
Apache::FilterRec
The following filter handler configuration directives are available:
PerlInputFilterHandler
See PerlInputFilterHandler.
PerlOutputFilterHandler
See PerlOutputFilterHandler.
PerlSetInputFilter
See PerlSetInputFilter.
PerlSetOutputFilter
See HTTP protocol handlers.
PerlPostReadRequestHandler
See PerlPostReadRequestHandler.
PerlTransHandler
See PerlTransHandler.
PerlMapToStorageHandler
See PerlMapToStorageHandler.
PerlInitHandler
See PerlInitHandler.
PerlHeaderParserHandler
See PerlHeaderParserHandler.
See PerlAccessHandler.
See PerlAuthenHandler.
See PerlAuthzHandler.
PerlTypeHandler
See PerlTypeHandler.
PerlFixupHandler
See PerlFixupHandler.
See PerlResponseHandler.
See PerlLogHandler.
See PerlCleanupHandler.
These directives are enabled only in a threaded mod_perl+Apache combo:
PerlInterpStart
The number of interpreters to clone at startup time.
Default value: 3
PerlInterpMax
If all running interpreters are in use, mod_perl will clone new interpreters to handle the request, up until this number of interpreters is reached. when PerlInterpMax is reached, mod_perl will block (via COND_WAIT()) until one becomes available (signaled via COND_SIGNAL()).
Default value: 5
PerlInterpMinSpare
The minimum number of available interpreters this parameter will clone interpreters up to PerlInterpMax, before a request comes in.
PerlInterpMaxSpare
mod_perl will throttle down the number of interpreters to this number as those in use become available.
PerlInterpMaxRequests
The maximum number of requests an interpreter should serve, the interpreter is destroyed when the number is reached and replaced with a fresh clone.
Default value: 2000
PerlInterpScope
As mentioned, when a request in a threaded mpm is handled by mod_perl, an interpreter must be pulled from the interpreter pool. The interpreter is then only available to the thread that selected it, until it is released back into the interpreter pool. By default, an interpreter will be held for the lifetime of the request, equivalent to this configuration:
PerlInterpScope request
For example, if a PerlAccessHandler is configured, an interpreter will be selected before it is run and not released until after the logging phase.
Interpreters will be shared across sub-requests by default, however, it is possible to configure the interpreter scope to be per-sub-request on a per-directory basis:
PerlInterpScope subrequest
With this configuration, an autoindex generated page, for example, would select an interpreter for each item in the listing that is configured with a Perl*Handler.
It is also possible to configure the scope to be per-handler:
PerlInterpScope handler
For example if PerlAccessHandler is configured, an interpreter will be selected before running the handler, and put back immediately afterwards, before Apache moves onto the next phase. If a PerlFixupHandler is configured further down the chain, another interpreter will be selected and again put back afterwards, before PerlResponseHandler is run.
For protocol handlers, the interpreter is held for the lifetime of the connection. However, a C protocol module might hook into mod_perl (e.g. mod_ftp) and provide a request_rec record. In this case, the default scope is that of the request. Should a mod_perl handler want to maintain state for the lifetime of an ftp connection, it is possible to do so on a per-virtualhost basis:
request_rec
PerlInterpScope connection
Default value: request
request
PerlTrace
The PerlTrace is used for tracing the mod_perl execution. This directive is enabled when mod_perl is compiled with the MP_TRACE=1 option.
MP_TRACE=1
To enable tracing, add to httpd.conf:
PerlTrace [level]
where level is either:
level
all
which sets maximum logging and debugging levels;
a combination of one or more option letters from the following list:
a Apache API interaction c configuration for directive handlers d directive processing f filters e environment variables g globals management h handlers i interpreter pool management m memory allocations o I/O r Perl runtime interaction s Perl sections t benchmark-ish timings
Tracing options add to the previous setting and don't override it. So for example:
PerlTrace c ... PerlTrace f
will set tracing level first to 'c' and later to 'cf'. If you wish to override settings, unset any previous setting by assigning 0 (zero), like so:
PerlTrace c ... PerlTrace 0 PerlTrace f
now the tracing level is set only to 'f'. You can't mix the number 0 with letters, it must be alone.
When PerlTrace is not specified, the tracing level will be set to the value of the $ENV{MOD_PERL_TRACE} environment variable.
$ENV{MOD_PERL_TRACE}
The following table shows where in the configuration files mod_perl configuration directives are allowed to appear, what kind and how many arguments they expect:
General directives:
Directive Arguments Scope -------------------------------------------- PerlSwitches ITERATE SRV PerlRequire ITERATE SRV PerlModule ITERATE SRV PerlLoadModule RAW_ARGS SRV PerlOptions ITERATE DIR PerlSetVar TAKE2 DIR PerlAddVar ITERATE2 DIR PerlSetEnv TAKE2 DIR PerlPassEnv TAKE1 SRV <Perl> Sections RAW_ARGS SRV PerlTrace TAKE1 SRV
Handler assignment directives:
Directive Arguments Scope -------------------------------------------- PerlOpenLogsHandler ITERATE SRV PerlPostConfigHandler ITERATE SRV PerlChildInitHandler ITERATE SRV PerlChildExitHandler ITERATE SRV PerlPreConnectionHandler ITERATE SRV PerlProcessConnectionHandler ITERATE SRV PerlPostReadRequestHandler ITERATE SRV PerlTransHandler ITERATE SRV PerlMapToStorageHandler ITERATE SRV PerlInitHandler ITERATE DIR PerlHeaderParserHandler ITERATE DIR PerlAccessHandler ITERATE DIR PerlAuthenHandler ITERATE DIR PerlAuthzHandler ITERATE DIR PerlTypeHandler ITERATE DIR PerlFixupHandler ITERATE DIR PerlResponseHandler ITERATE DIR PerlLogHandler ITERATE DIR PerlCleanupHandler ITERATE DIR PerlInputFilterHandler ITERATE DIR PerlOutputFilterHandler ITERATE DIR PerlSetInputFilter ITERATE DIR PerlSetOutputFilter ITERATE DIR
Perl Interpreter management directives:
Directive Arguments Scope -------------------------------------------- PerlInterpStart TAKE1 SRV PerlInterpMax TAKE1 SRV PerlInterpMinSpare TAKE1 SRV PerlInterpMaxSpare TAKE1 SRV PerlInterpMaxRequests TAKE1 SRV PerlInterpScope TAKE1 DIR
mod_perl 1.0 back-compatibility directives:
Directive Arguments Scope -------------------------------------------- PerlHandler ITERATE DIR PerlSendHeader FLAG DIR PerlSetupEnv FLAG DIR PerlTaintCheck FLAG SRV PerlWarn FLAG SRV
The Arguments column represents the type of arguments directives accepts, where:
Expects a list of arguments.
Expects one argument, followed by at least one or more arguments.
Expects one argument only.
Expects two arguments only.
One of On or Off (case insensitive).
On
Off
The function parses the command line by itself.
The Scope column shows the location the directives are allowed to appear in:
Global configuration and <VirtualHost> (mnemonic: SeRVer). These directives are defined as RSRC_CONF in the source code.
RSRC_CONF
<Directory>, <Location>, <Files> and all their regular expression variants (mnemonic: DIRectory). These directives can also appear in .htaccess files. These directives are defined as OR_ALL in the source code.
<Files>
OR_ALL
These directives can also appear in the global server configuration and <VirtualHost>.
Apache specifies other allowed location types which are currently not used by the core mod_perl directives and their definition can be found in include/httpd_config.h (hint: search for RSRC_CONF).
Also see Stacked Handlers.
Inside httpd.conf one can do conditional configuration based on the define options passed at the server startup. For example:
<IfDefine PERLDB> <Perl> use Apache::DB (); Apache::DB->init; </Perl> <Location /> PerlFixupHandler Apache::DB </Location> </IfDefine>
So only when the server is started as:
% httpd C<-DPERLDB> ...
The configuration inside IfDefine will have an effect. If you want to have some configuration section to have an effect if a certain define wasn't defined use !, for example here is the opposite of the previous example:
IfDefine
!
<IfDefine !PERLDB> # ... </IfDefine>
If you need to access any of the startup defines in the Perl code you use Apache::ServerUtil::exists_config_define(). For example in a startup file you can say:
Apache::ServerUtil::exists_config_define()
use Apache::ServerUtil (); if (Apache::ServerUtil::exists_config_define("PERLDB")) { require Apache::DB; Apache::DB->init; }
For example to check whether the server has been started in a single mode use:
if (Apache::ServerUtil::exists_config_define("ONE_PROCESS")) { print "Running in a single mode"; }
MODPERL2
When running under mod_perl 2.0 a special configuration "define" symbol MODPERL2 is enabled internally, as if the server had been started with -DMODPERL2. For example this can be used to write a configuration file which needs to do something different whether it's running under mod_perl 1.0 or 2.0:
-DMODPERL2
<IfDefine MODPERL2> # 2.0 configuration </IfDefine> <IfDefine !MODPERL2> # else </IfDefine>
From within Perl code this can be tested with Apache::ServerUtil::exists_config_define(), for example:
use Apache::ServerUtil (); if (Apache::ServerUtil::exists_config_define("MODPERL2")) { # some 2.0 specific code }
For now refer to the Apache::Directive manpage and the test t/response/TestApache/conftree.pm in the mod_perl source distribution.
META: need help to write the tutorial section on this with examples.
You can always adjust contents of @INC before the server starts. There are several ways to do that.
startup.pl
In the startup file you can use the lib pragma like so:
lib
use lib qw(/home/httpd/project1/lib /tmp/lib); use lib qw(/home/httpd/project2/lib);
httpd.conf
In httpd.conf you can use the PerlSwitches directive to pass arguments to perl as you do from the command line, e.g.:
PerlSwitches -I/home/httpd/project1/lib -I/tmp/lib PerlSwitches -I/home/httpd/project2/lib
PERL5LIB
PERLLIB
The effect of the PERL5LIB and PERLLIB environment variables on @INC is described in the perlrun manpage. mod_perl 2.0 doesn't do anything special about them.
It's important to remind that both PERL5LIB and PERLLIB are ignored when the taint mode (PerlSwitches -T) is in effect. Since you want to make sure that your mod_perl server is running under the taint mode, you can't use the PERL5LIB and PERLLIB environment variables.
PerlSwitches -T
However there is the perl5lib module on CPAN, which, if loaded, bypasses perl's security and will affect @INC. Use it only if you know what you are doing.
If Perl used with mod_perl was built with ithreads support one can specify different @INC values for different VirtualHosts, using a combination of PerlOptions +Parent and PerlSwitches. For example:
PerlOptions +Parent
<VirtualHost ...> ServerName dev1 PerlOptions +Parent PerlSwitches -I/home/dev1/lib/perl PerlModule Apache2 </VirtualHost> <VirtualHost ...> ServerName dev2 PerlOptions +Parent PerlSwitches -I/home/dev2/lib/perl PerlModule Apache2 </VirtualHost>
Maintainer is the person(s) you should contact with updates, corrections and patches.
Stas Bekman <stas (at) stason.org>
Doug MacEachern <dougm (at) covalent.net>
Only the major authors are listed above. For contributors see the Changes file.
To install mod_perl, copy and paste the appropriate command in to your terminal.
cpanm
cpanm mod_perl
CPAN shell
perl -MCPAN -e shell install mod_perl
For more information on module installation, please visit the detailed CPAN module installation guide.