CGI::PSGI(3)

NAME
CGI::PSGI - Adapt CGI.pm to the PSGI protocol

SYNOPSIS
  use CGI::PSGI;

  my $app = sub {
      my $env = shift;
      my $q = CGI::PSGI->new($env);
      return [ $q->psgi_header, [ $body ] ];
  };

DESCRIPTION
This module is for web application framework developers who currently uses CGI to handle query parameters, and would like for the frameworks to comply with the PSGI protocol.

Only slight modifications should be required if the framework is already collecting the body content to print to STDOUT at one place (rather using the print-as-you-go approach).

On the other hand, if you are an "end user" of CGI.pm and have a CGI script that you want to run under PSGI web servers, this module might not be what you want. Take a look at CGI::Emulate::PSGI instead.

Your application, typically the web application framework adapter should update the code to do "CGI::PSGI->new($env)" instead of "CGI->new" to create a new CGI object. (This is similar to how CGI::Fast object is initialized in a FastCGI environment.)

INTERFACES SUPPORTED
Only the object-oriented interface of CGI.pm is supported through CGI::PSGI. This means you should always create an object with "CGI::PSGI->new($env)" and should call methods on the object.

The function-based interface like "use CGI ':standard'" does not work with this module.

METHODS
CGI::PSGI adds the following extra methods to CGI.pm:

  env
  $env = $cgi->env;

Returns the PSGI environment in a hash reference. This allows CGI.pm-based application frameworks such as CGI::Application to access PSGI extensions, typically set by Plack Middleware components.

So if you enable Plack::Middleware::Session, your application and plugin developers can access the session via:

  $cgi->env->{'plack.session'}->get("foo");

Of course this should be coded carefully by checking the existence of "env" method as well as the hash key "plack.session".

  psgi_header
 my ($status_code, $headers_aref) = $cgi->psgi_header(%args);

Works like CGI.pm's header(), but the return format is modified. It returns an array with the status code and arrayref of header pairs that PSGI requires.

If your application doesn't use "$cgi->header", you can ignore this method and generate the status code and headers arrayref another way.

  psgi_redirect
 my ($status_code, $headers_aref) = $cgi->psgi_redirect(%args);

Works like CGI.pm's redirect(), but the return format is modified. It returns an array with the status code and arrayref of header pairs that PSGI requires.

If your application doesn't use "$cgi->redirect", you can ignore this method and generate the status code and headers arrayref another way.

LIMITATIONS
Do not use CGI::Pretty or something similar in your controller. The module messes up CGI's DIY autoloader and breaks CGI::PSGI (and potentially other) inheritance.

AUTHOR
Tatsuhiko Miyagawa <miyagawa@bulknews.net>

Mark Stosberg <mark@summersault.com>

LICENSE
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO
CGI, CGI::Emulate::PSGI