NAME
   CGI::Application::Plugin::CAPTCHA - Easily create, use, and verify
   CAPTCHAs in CGI::Application-based web applications.

VERSION
   Version 0.04

SYNOPSIS
       # In your CGI::Application-based web application module. . .
       use CGI::Application::Plugin::CAPTCHA;

       sub setup
       {
           my $self = shift;

           $self->run_modes([ qw/
               create
               # Your other run modes go here
           /]);

           $self->captcha_config(
               IMAGE_OPTIONS    => {
                   width    => 150,
                   height   => 40,
                   lines    => 10,
                   font     => "/Library/Fonts/Arial",
                   ptsize   => 18,
                   bgcolor  => "#FFFF00",
               },
               CREATE_OPTIONS   => [ 'ttf', 'rect' ],
               PARTICLE_OPTIONS => [ 300 ],
           );
       }

       # Create a run mode that calls the CAPTCHA creation method...
       sub create
       {
           my $self = shift;
           return $self->captcha_create;
       }

       # In a template far, far away. . .
       <img src="/delight/Ident/create"> (to generate a CAPTCHA image)

       # Back in your application, to verify the CAPTCHA...
       sub some_other_runmode
       {
           my $self    = shift;
           my $request = $self->query;

           return unless $self->captcha_verify($request->cookie("hash"), $request->param("verify"));
       }

DESCRIPTION
   "CGI::Application::Plugin::CAPTCHA" allows programmers to easily add and
   verify CAPTCHAs in their CGI::Application-derived web applications.

   A CAPTCHA (or Completely Automated Public Turing Test to Tell Computers
   and Humans Apart) is an image with a random string of characters. A user
   must successfully enter the random string in order to submit a form.
   This is a simple (yet annoying) procedure for humans to complete, but
   one that is significantly more difficult for a form-stuffing script to
   complete without having to integrate some sort of OCR.

   CAPTCHAs are not a perfect solution. Any skilled, diligent cracker will
   eventually be able to bypass a CAPTCHA, but it should be able to shut
   down your average script-kiddie.

   "CGI::Application::Plugin::CAPTCHA" is a wrapper for GD::SecurityImage.
   It makes it more convenient to access GD::SecurityImage functionality,
   and gives a more CGI::Application-like way of doing it.

   When a CAPTCHA is created with this module, raw image data is
   transmitted from your web application to the client browser. A cookie
   containing a checksum is also transmitted with the image. When the
   client submits their form for processing (along with their verification
   of the random string), "captcha_verify()" generates a checksum of the
   verification string the user entered. If the newly generated checksum
   matches the checksum found in the cookie, we trust that the CAPTCHA has
   been successfully entered, and we allow the user to continue processing
   their form.

   The checksum is generated by taking the string in question, and joining
   it with a SECRET. We then generate an SHA1 hex digest of the resulting
   string. The end user will not be able to generate their own checksums to
   bypass the CAPTCHA check, because they do not know the value of our
   SECRET. This means it is important to choose a good value for your
   SECRET.

   An easy way to generate a relatively good secret is to run the following
   perl snippet:

     perl -MDigest::SHA1=sha1_base64 -le 'print sha1_base64($$,time(),rand(9999))'

   The author recognizes that the transmission of a cookie with the CAPTCHA
   image may not be a popular decision, and welcomes any patches from those
   who can provide an equally easy-to-implement solution.

FUNCTIONS
 captcha_config()
   This method is used to customize how new CAPTCHA images will be created.
   Values specified here are passed along to the appropriate functions in
   GD::SecurityImage when a new CAPTCHA is created.

   It is recommended that you call "captcha_config()" in the
   "cgiapp_init()" method of your CGI::Application base class, and in the
   "setup()" method of any derived applications.

   The following parameters are currently accepted:

  IMAGE_OPTIONS
   This specifies what options will be passed to the constructor of
   GD::SecurityImage. Please see the documentation for GD::SecurityImage
   for more information.

  CREATE_OPTIONS
   This specifies what options will be passed to the "create()" method of
   GD::SecurityImage. Please see the documentation for GD::SecurityImage
   for more information.

  PARTICLE_OPTIONS
   This specifies what options will be passed to the "particle()" method of
   GD::SecurityImage. Please see the documentation for GD::SecurityImage
   for more information.

  SECRET
   This specifies the secret that will be used when generating the checksum
   hash.

 captcha_create()
   Creates the CAPTCHA image, and return a cookie with the encrypted hash
   of the random string. Takes no arguments.

   The cookie created in this method is named "hash", and contains only the
   encrypted hash. Future versions of this module will allow you to specify
   cookie options in greater detail.

 captcha_verify()
   Verifies that the value entered by the user matches what was in the
   CAPTCHA image. Argument 1 is the encrypted hash from the cookie sent by
   "captcha_create()", and argument 2 is the value the user entered to
   verify the CAPTCHA image. Returns true if the CAPTCHA was successfully
   verified, else returns false.

AUTHOR
   Jason A. Crome, "<[email protected]>"

TODO
   *   Allow "captcha_config()" to take cookie configuration arguments.

   *   Allow the plugin to actually create a run mode in your
       CGI::Application-based webapp without the developer having to
       manually create one.

BUGS
   Please report any bugs or feature requests to
   "[email protected]", or through the web
   interface at
   <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=CGI-Application-Plugin-C
   APTCHA>. I will be notified, and then you'll automatically be notified
   of progress on your bug as I make changes.

CONTRIBUTING
   Patches, questions, and feedback are welcome.

ACKNOWLEDGEMENTS
   A big thanks to Cees Hek for providing a great module for me to borrow
   code from (CGI::Application::Plugin::Session), to Michael Peters and
   Tony Fraser for all of their valuable input, and to the rest who
   contributed ideas and criticisms on the CGI::Application mailing list.

   Additional thanks to chorny and Cees for the various bug fixes and
   patches they have submitted.

SEE ALSO
   CGI::Application GD::SecurityImage Wikipedia entry for CAPTCHA -
   <http://en.wikipedia.org/wiki/Captcha>

COPYRIGHT & LICENSE
   Copyright 2005-2011 Jason A. Crome, all rights reserved.

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

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.