NAME
    Business::PayPal::IPN - Perl extension that implements PayPal IPN v1.4

SYNOPSIS
      use Business::PayPal::IPN;

      my $ipn = new Business::PayPal::IPN() or die Business::PayPal::IPN->error();

      # if we came this far, you're guaranteed it went through,
      # and the transaction took place. But now you need to check
      # the status of the transaction, to see if it was completed
      # or still pending
      if ( $ipn->completed ) {
        # do something with it
      }

DESCRIPTION
    Business::PayPal::IPN implements PayPal IPN version 1.4. It validates
    transactions and gives you means to get notified of payments to your
    PayPal account. If you don't already know what PayPal IPN is this
    library may not be for you ;-). Consult with respective manuals provided
    by PayPal.com.

  WARNING

    $Revision: 1.3 $ of Business::PayPal::IPN supports version 1.4 of the
    API. This was the latest version as of Wednesday, January 22, 2003.
    Supported version number is available in
    $Business::PayPal::IPN::SUPPORTEDV global variable.

    Note: If PayPal introduces new response variables, Business::PayPal::IPN
    automatically supports those variables thanks to AUTOLOAD. For any
    further updates, you can contact me or send me a patch.

PAYPAL IPN OVERVIEW
    As soon as you receive payment to your PayPal account, PayPal posts the
    transaction details to your specified URL, which you either configure in
    your PayPal preferences, or in your HTML forms' "notify_url" hidden
    field.

    When the payment details are received from, supposedly, PayPal server,
    your application should check with the PayPal server to make sure it is
    indeed a valid transaction, and that PayPal is aware of it. This can be
    achieved by re-submitting the transaction details back to
    https://www.paypal.com/cgi-bin/webscr and check the integrity of the
    data.

    If the transaction is valid, PayPal will respond to you with a single
    string "VERIFIED", and you can proceed safely. If the transaction is not
    valid, you will receive "INVALID", and you can log the request for
    further investigation.

    Business::PayPal::IPN is the library which encapsulates all the above
    complexity into this compact form:

      my $ipn = new Business::PayPal::IPN() or die Business::PayPal::IPN->error();

      # if we come this far, we're guaranteed it was a valid transaction.
      if ( $ipn->completed() ) {
        # means the funds are already in our paypal account. But we should
        # still check against duplicates transaction ids to ensure we're
        # no logging the same transaction twice. 

      } elsif ( $ipn->pending() ) {
        # the payment was made to your account, but its status is still pending
        # $ipn->pending() also returns the reason why it is so.

      } elsif ( $ipn->denied() ) {
        # the payment denied

      } elsif ( $ipn->failed() ) {
        # the payment failed

      }

PREREQUISITES
    *   LWP - to make HTTP requests

    *   Crypt::SSLeay - to enable LWP perform https (SSL) requests. If for
        any reason you are not be able to install Crypt::SSLeay, you will
        need to update $Business::PayPal::IPN::GTW to proper, non-ssl URL.

METHODS
    *   "new()" - constructor. Validates the transaction and returns IPN
        object if everything was successful. Optionally you may pass it
        query and ua options. query denotes the CGI object to be used. ua
        denotes the user agent object. If ua is missing, it will use
        LWP::UserAgent by default.

    *   "query()" - can also be accessed via "cgi()" alias, returns
        respective query object

    *   "response()" - returns HTTP::Response object, which is the content
        returned while verifying transaction through PayPal. You normally
        never need this method. In case you do for any reason, here it is

    *   "user_agent()" - returns user agent object used by PayPal to verify
        the transaction with PayPal.

    Business::PayPal::IPN supports all the variables supported by PayPal IPN
    independent of its version. To access the value of any variable, use the
    corresponding method name. For example, if you want to get the first
    name of the user who made the payment ('first_name' variable):

      my $fname = $ipn->first_name();

    To get the transaction id ('txn_id' variable):

      my $txn = $ipn->txn_id();

    To get payment type ('payment_type' variable)

      $type = $ipn->payment_type();

    and so on. For the list of all the available variables, consult IPN
    Manual provided by PayPal Developer Network. You can find the link at
    the bottom of http://www.paypal.com.

    In addition to the above scheme, the library also provides "status()"
    method, which is a shortcut to "payment_status()"

VARIABLES
    Following global variables are available:

    *   $Business::PayPal::IPN::GTW - gateway url to PayPal's Web Script.
        Default is "https://www.paypal.com/cgi-bin/webscr", which you may
        not want to change.

    *   $Business::PayPal::IPN::SUPPORTEDV - supported version of PayPal's
        IPN API. Default value is "1.4". You can modify it before creating
        ipn object (as long as you know what you are doing. If not don't
        touch it!)

    *   $Business::PayPal::IPN::VERSION - version of the library

AUTHOR
    Sherzod B. Ruzmetov <sherzodr@cpan.org>

COPYRIGHT AND LICENSE
    Copyright 2003 by Sherzod B. Ruzmetov.

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

REVISION
    $Revision: 1.3 $

