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Stevan Little
and 12 contributors


Web::Machine - A Perl port of Webmachine


version 0.13


  use strict;
  use warnings;

  use Web::Machine;

      package HelloWorld::Resource;
      use strict;
      use warnings;

      use parent 'Web::Machine::Resource';

      sub content_types_provided { [{ 'text/html' => 'to_html' }] }

      sub to_html {
                  <title>Hello World Resource</title>
                  <h1>Hello World</h1>

  Web::Machine->new( resource => 'HelloWorld::Resource' )->to_app;


Web::Machine provides a RESTful web framework modeled as a state machine. You define one or more resource classes. Each resource represents a single RESTful URI end point, such as a user, an email, etc. The resource class can also be the target for POST requests to create a new user, email, etc.

Each resource is a state machine, and each request for a resource is handled by running the request through that state machine.

Web::Machine is built on top of Plack, but it handles the full request and response cycle.

See Web::Machine::Manual for more details on using Web::Machine in general, and how Web::Machine and Plack interact.

This is a port of Webmachine, actually it is much closer to the Ruby version, with a little bit of the JavaScript version and even some of the Python version thrown in for good measure.


This module is extremely young and it is a port of an pretty young (June 2011) module in another language (ruby), which itself is a port of a still kind of young module (March 2009) in yet another language (Erlang). But that all said, it really seems like a sane idea and so I stole it and ported it to Perl.


NOTE: This module is a Plack::Component subclass and so follows the interface set forward by that module.

new( resource => $resource_classname, ?resource_args => $arg_list, ?tracing => 1|0, ?streaming => 1|0 )

The constructor expects to get a $resource_classname, which it will use to create an instance of the resource class. If that class requires any additional arguments, they can be specified with the resource_args parameter. It can also take an optional tracing parameter which it will pass onto the Web::Machine::FSM, and an optional streaming parameter, which if true will run the request in a PSGI streaming response, which can be useful if you need to run your content generation asynchronously.

inflate_request( $env )

This takes a raw PSGI $env and inflates it into a Plack::Request instance. By default this also uses HTTP::Headers::ActionPack to inflate the headers of the request to be complex objects.


This will create the Web::Machine::FSM object to run. It will get passed the value of the tracing constructor parameter.

create_resource( $request )

This will create the Web::Machine::Resource instance using the class specified in the resource constructor parameter. It will pass in the $request object and call new_response on the $request object to get a Plack::Response instance.

finalize_response( $response )

Given a $response which is a Plack::Response object, this will finalize it and return a raw PSGI response.

call( $env )

This is the call method overridden from the Plack::Component superclass.


If you set the WM_DEBUG environment variable to 1 we will print out information about the path taken through the state machine to STDERR.


Original Erlang - https://github.com/basho/webmachine
Ruby port - https://github.com/seancribbs/webmachine-ruby
Node JS port - https://github.com/tautologistics/nodemachine
Python port - https://github.com/davisp/pywebmachine


Stevan Little <stevan.little@iinteractive.com>


  • Andreas Marienborg <andreas.marienborg@gmail.com>

  • Andrew Nelson <anelson@cpan.org>

  • Arthur Axel 'fREW' Schmidt <frioux@gmail.com>

  • Carlos Fernando Avila Gratz <cafe@q1software.com>

  • Dave Rolsky <autarch@urth.org>

  • Fayland Lam <fayland@gmail.com>

  • Gregory Oschwald <goschwald@maxmind.com>

  • Jesse Luehrs <doy@tozt.net>

  • John SJ Anderson <genehack@genehack.org>

  • Olaf Alders <olaf@wundersolutions.com>

  • Thomas Sibley <tsibley@cpan.org>


This software is copyright (c) 2013 by Infinity Interactive, Inc..

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.