plack::component(3pm) [debian man page]

Plack::Component(3pm)					User Contributed Perl Documentation				     Plack::Component(3pm)

NAME

       Plack::Component - Base class for PSGI endpoints

SYNOPSIS

	 package Plack::App::Foo;
	 use parent qw( Plack::Component );

	 sub call {
	     my($self, $env) = @_;
	     # Do something with $env

	     my $res = ...; # create a response ...

	     # return the response
	     return $res;
	 }

DESCRIPTION

       Plack::Component is the base class shared between Plack::Middleware and Plack::App::* modules. If you are writing middleware, you should
       inherit from Plack::Middleware, but if you are writing a Plack::App::* you should inherit from this directly.

REQUIRED METHOD

       call ($env)
	   You are expected to implement a "call" method in your component. This is where all the work gets done. It receives the PSGI $env hash-
	   ref as an argument and is expected to return a proper PSGI response value.

METHODS

       new (%opts | \%opts)
	   The constructor accepts either a hash or a hash-ref and uses that to create the instance with. It will call no other methods and simply
	   return the instance that is created.

       prepare_app
	   This method is called by "to_app" and is meant as a hook to be used to prepare your component before it is packaged as a PSGI $app.

       to_app
	   This is the method used in several parts of the Plack infrastructure to convert your component into a PSGI $app. You should not ever
	   need to override this method, it is recommended to use "prepare_app" and "call" instead.

       response_cb
	   This is a wrapper for "response_cb" in Plack::Util. See "RESPONSE CALLBACK" in Plack::Middleware for details.

OBJECT LIFECYCLE

       Objects for the derived classes (Plack::App::* or Plack::Middleware::*) are created at the PSGI application compile phase using "new",
       "prepare_app" and "to_app", and the created object persists during the web server lifecycle, unless it is running on the non-persistent
       environment like CGI. "call" is invoked against the same object whenever a new request comes in.

       You can check if it is running in a persistent environment by checking "psgi.run_once" key in the $env being true (non-persistent) or false
       (persistent), but it is best for you to write your middleware safely for a persistent environment. To accomplish that, you should avoid
       saving per-request data like $env in your object.

BACKWARDS COMPATIBILITY

       The Plack::Middleware module used to inherit from Class::Accessor::Fast, which has been removed in favor of the Plack::Util::Accessor
       module. When developing new components it is recommended to use Plack::Util::Accessor like so:

	 use Plack::Util::Accessor qw( foo bar baz );

       However, in order to keep backwards compatibility this module provides a "mk_accessors" method similar to Class::Accessor::Fast. New code
       should not use this and use Plack::Util::Accessor instead.

SEE ALSO

       Plack Plack::Builder Plack::Middleware

perl v5.14.2							    2011-06-22						     Plack::Component(3pm)

Check Out this Related Man Page

Plack::Runner(3pm)					User Contributed Perl Documentation					Plack::Runner(3pm)

NAME

       Plack::Runner - plackup core

SYNOPSIS

	 # Your bootstrap script
	 use Plack::Runner;
	 my $app = sub { ... };

	 my $runner = Plack::Runner->new;
	 $runner->parse_options(@ARGV);
	 $runner->run($app);

DESCRIPTION

       Plack::Runner is the core of plackup runner script. You can create your own frontend to run your application or framework, munge command
       line options and pass that to "run" method of this class.

       "run" method does exactly the same thing as the plackup script does, but one notable addition is that you can pass a PSGI application code
       reference directly to the method, rather than via ".psgi" file path or with "-e" switch. This would be useful if you want to make an
       installable PSGI application.

       Also, when "-h" or "--help" switch is passed, the usage text is automatically extracted from your own script using Pod::Usage.

NOTES

       Do not directly call this module from your ".psgi", since that makes your PSGI application unnecessarily depend on plackup and won't run
       other backends like Plack::Handler::Apache2 or mod_psgi.

       If you really want to make your ".psgi" runnable as a standalone script, you can do this:

	 my $app = sub { ... };

	 unless (caller) {
	     require Plack::Runner;
	     my $runner = Plack::Runner->new;
	     $runner->parse_options(@ARGV);
	     return $runner->run($app);
	 }

	 return $app;

       WARNING: this section used to recommend "if (__FILE__ eq $0)" but it's known to be broken since Plack 0.9971, since $0 is now always set to
       the .psgi file path even when you run it from plackup.

SEE ALSO

       plackup

perl v5.14.2							    2012-03-21							Plack::Runner(3pm)

Linux and UNIX Man Pages

plack::component(3pm) [debian man page]

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