NAME

Captcha::reCAPTCHA - A Perl implementation of the reCAPTCHA API

VERSION

This document describes Captcha::reCAPTCHA version 0.6

SYNOPSIS

    use Captcha::reCAPTCHA;

    my $c = Captcha::reCAPTCHA->new;

    # Output form
    print $c->get_html( 'your public key here' );

    # Verify submission
    my $result = $c->check_answer(
        'your private key here', $ENV{'REMOTE_ADDR'},
        $challenge, $response
    );

    if ( $result->{is_valid} ) {
        print "Yes!";
    }
    else {
        # Error
        $error = $result->{error};
    }

For complete examples see the /examples subdirectory

DESCRIPTION

reCAPTCHA is a hybrid mechanical turk and captcha that allows visitors who complete the captcha to assist in the digitization of books.

From http://recaptcha.net/learnmore.html:

    reCAPTCHA improves the process of digitizing books by sending words that
    cannot be read by computers to the Web in the form of CAPTCHAs for
    humans to decipher. More specifically, each word that cannot be read
    correctly by OCR is placed on an image and used as a CAPTCHA. This is
    possible because most OCR programs alert you when a word cannot be read
    correctly.

This Perl implementation is modelled on the PHP interface that can be found here:

http://recaptcha.net/plugins/php/

INTERFACE

new

Create a new Captcha::reCAPTCHA.

reCAPTCHA

To use reCAPTCHA you need to register your site here:

https://admin.recaptcha.net/recaptcha/createsite/

get_html( $pubkey, $error, $use_ssl, $options )

Generates HTML to display the captcha.

    print $captcha->get_html( $PUB, $err );

$pubkey

Your reCAPTCHA public key, from the API Signup Page

$error

Optional. If this string is set, the reCAPTCHA area will display the error code given. This error code comes from $response->{error}.

$use_ssl

Optional. Should the SSL-based API be used? If you are displaying a page to the user over SSL, be sure to set this to true so an error dialog doesn't come up in the user's browser.

$options

Optional. A reference to a hash of options for the captcha. See get_options_setter for more details.

Returns a string containing the HTML that should be used to display the captcha.

get_options_setter( $options )

You can optionally customize the look of the reCAPTCHA widget with some JavaScript settings. get_options_setter returns a block of Javascript wrapped in <script> .. </script> tags that will set the options to be used by the widget.

$options is a reference to a hash that may contain the following keys:

theme

Defines which theme to use for reCAPTCHA. Possible values are 'red', 'white' or 'blackglass'. The default is 'red'.

tabindex

Sets a tabindex for the reCAPTCHA text box. If other elements in the form use a tabindex, this should be set so that navigation is easier for the user. Default: 0.

check_answer

After the user has filled out the HTML form, including their answer for the CAPTCHA, use check_answer to check their answer when they submit the form. The user's answer will be in two form fields, recaptcha_challenge_field and recaptcha_response_field. The reCAPTCHA library will make an HTTP request to the reCAPTCHA server and verify the user's answer.

$privkey

Your reCAPTCHA private key, from the API Signup Page.

$remoteip

The user's IP address, in the format 192.168.0.1.

$challenge

The value of the form field recaptcha_challenge_field

$response

The value of the form field recaptcha_response_field.

Returns a reference to a hash containing two fields: is_valid and error.

    my $result = $c->check_answer(
        'your private key here', $ENV{'REMOTE_ADDR'},
        $challenge, $response
    );

    if ( $result->{is_valid} ) {
        print "Yes!";
    }
    else {
        # Error
        $error = $result->{error};
    }

See the /examples subdirectory for examples of how to call check_answer.

reCAPTCHA Mailhide

To use reCAPTCHA Mailhide you need to get a public, private key pair from this page:

http://mailhide.recaptcha.net/apikey

The Mailhide API consists of two methods mailhide_html and mailhide_url. The methods have the same parameters.

The _html version returns HTML that can be directly put on your web page. The username portion of the email that is passed in is truncated and replaced with a link that calls Mailhide. The _url version gives you the url to decode the email and leaves it up to you to place the email in HTML.

mailhide_url( $pubkey, $privkey, $email )

Generate a link that will decode the specified email address.

$pubkey

The Mailhide public key from the signup page

$privkey

The Mailhide private key from the signup page

$email

The email address you want to hide.

Returns a URL that when clicked will allow the user to decode the hidden email address.

mailhide_html( $pubkey, $privkey, $email )

Generates HTML markup to embed a Mailhide protected email address on a page.

The arguments are the same as for mailhide_url.

Returns a string containing HTML that may be embedded directly in a web page.

CONFIGURATION AND ENVIRONMENT

Captcha::reCAPTCHA requires no configuration files or environment variables.

To use reCAPTCHA sign up for a key pair here:

https://admin.recaptcha.net/recaptcha/createsite/

To use Mailhide get a public/private key pair here:

http://mailhide.recaptcha.net/apikey

DEPENDENCIES

LWP::UserAgent, Crypt::Rijndael, MIME::Base64,

INCOMPATIBILITIES

None reported .

BUGS AND LIMITATIONS

Doesn't currently implement Mailhide support.

No bugs have been reported.

Please report any bugs or feature requests to bug-captcha-recaptcha@rt.cpan.org, or through the web interface at http://rt.cpan.org.

AUTHOR

Andy Armstrong <andy@hexten.net>

LICENCE AND COPYRIGHT

Copyright (c) 2007, Andy Armstrong <andy@hexten.net>. All rights reserved.

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

DISCLAIMER OF WARRANTY

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.