<?php
/*******************************************************************************
 *                      PHP Paypal IPN Integration Class
 *******************************************************************************
 *      Author:     Micah Carrick
 *      Email:      email@micahcarrick.com
 *      Website:    http://www.micahcarrick.com
 *
 *      File:       paypal.class.php
 *      Version:    1.3.0
 *      Copyright:  (c) 2005 - Micah Carrick 
 *                  You are free to use, distribute, and modify this software 
 *                  under the terms of the GNU General Public License.  See the
 *                  included license.txt file.
 *      
 *******************************************************************************
 *  VERION HISTORY:
 *      v1.3.0 [10.10.2005] - Fixed it so that single quotes are handled the 
 *                            right way rather than simple stripping them.  This
 *                            was needed because the user could still put in
 *                            quotes.
 *  
 *      v1.2.1 [06.05.2005] - Fixed typo from previous fix :)
 *
 *      v1.2.0 [05.31.2005] - Added the optional ability to remove all quotes
 *                            from the paypal posts.  The IPN will come back
 *                            invalid sometimes when quotes are used in certian
 *                            fields.
 *
 *      v1.1.0 [05.15.2005] - Revised the form output in the submit_paypal_post
 *                            method to allow non-javascript capable browsers
 *                            to provide a means of manual form submission.
 *
 *      v1.0.0 [04.16.2005] - Initial Version
 *
 *******************************************************************************
 *  DESCRIPTION:
 *
 *      NOTE: See www.micahcarrick.com for the most recent version of this class
 *            along with any applicable sample files and other documentaion.
 *
 *      This file provides a neat and simple method to interface with paypal and
 *      The paypal Instant Payment Notification (IPN) interface.  This file is
 *      NOT intended to make the paypal integration "plug 'n' play". It still
 *      requires the developer (that should be you) to understand the paypal
 *      process and know the variables you want/need to pass to paypal to
 *      achieve what you want.  
 *
 *      This class handles the submission of an order to paypal aswell as the
 *      processing an Instant Payment Notification.
 *  
 *      This code is based on that of the php-toolkit from paypal.  I've taken
 *      the basic principals and put it in to a class so that it is a little
 *      easier--at least for me--to use.  The php-toolkit can be downloaded from
 *      http://sourceforge.net/projects/paypal.
 *      
 *      To submit an order to paypal, have your order form POST to a file with:
 *
 *          $p = new Paypal;
 *          $p->add_field('business', 'somebody@domain.com');
 *          $p->add_field('first_name', $_POST['first_name']);
 *          ... (add all your fields in the same manor)
 *          $p->submit_paypal_post();
 *
 *      To process an IPN, have your IPN processing file contain:
 *
 *          $p = new Paypal;
 *          if ($p->validate_ipn()) {
 *          ... (IPN is verified.  Details are in the ipn_data() array)
 *          }
 *
 *
 *      In case you are new to paypal, here is some information to help you:
 *
 *      1. Download and read the Merchant User Manual and Integration Guide from
 *         http://www.paypal.com/en_US/pdf/integration_guide.pdf.  This gives 
 *         you all the information you need including the fields you can pass to
 *         paypal (using add_field() with this class) aswell as all the fields
 *         that are returned in an IPN post (stored in the ipn_data() array in
 *         this class).  It also diagrams the entire transaction process.
 *
 *      2. Create a "sandbox" account for a buyer and a seller.  This is just
 *         a test account(s) that allow you to test your site from both the 
 *         seller and buyer perspective.  The instructions for this is available
 *         at https://developer.paypal.com/ as well as a great forum where you
 *         can ask all your paypal integration questions.  Make sure you follow
 *         all the directions in setting up a sandbox test environment, including
 *         the addition of fake bank accounts and credit cards.
 * 
 *******************************************************************************
*/

class Paypal {
    
   var $last_error;                 // holds the last error encountered
   
   var $ipn_log;                    // bool: log IPN results to text file?
   
   var $ipn_log_file;               // filename of the IPN log
   var $ipn_response;               // holds the IPN response from paypal   
   var $ipn_data = array();         // array contains the POST values for IPN
   
   var $fields = array();           // array holds the fields to submit to paypal

   
   function Paypal() {
       
      // initialization constructor.  Called when class is created.
      
      //$this->paypal_url = 'https://www.sandbox.paypal.com/cgi-bin/webscr';
      $this->paypal_url = 'https://www.paypal.com/cgi-bin/webscr';
      
      $this->last_error = '';
      
      $this->ipn_log_file = '.ipn_results.log';
      $this->ipn_log = true; 
      $this->ipn_response = '';
      
      // populate $fields array with a few default values.  See the paypal
      // documentation for a list of fields and their data types. These defaul
      // values can be overwritten by the calling script.

      $this->add_field('rm','2');           // Return method = POST
      $this->add_field('cmd','_xclick'); 
      
   }
   
   function add_field($field, $value) {
      
      // adds a key=>value pair to the fields array, which is what will be 
      // sent to paypal as POST variables.  If the value is already in the 
      // array, it will be overwritten.
            
      $this->fields["$field"] = $value;
   }

   function submit_paypal_post() {
 
      // this function actually generates an entire HTML page consisting of
      // a form with hidden elements which is submitted to paypal via the 
      // BODY element's onLoad attribute.  We do this so that you can validate
      // any POST vars from you custom form before submitting to paypal.  So 
      // basically, you'll have your own form which is submitted to your script
      // to validate the data, which in turn calls this function to create
      // another hidden form and submit to paypal.
 
      // The user will briefly see a message on the screen that reads:
      // "Please wait, your order is being processed..." and then immediately
      // is redirected to paypal.

      echo "<html>\n";
      //echo "<head><title>Processing Payment...</title></head>\n";
      echo "<body onLoad=\"document.forms['paypal_form'].submit();\">\n";
      //echo "<center><h3>";
      //echo " Redirecting to the paypal.</h3></center>\n";
      echo "<form method=\"post\" name=\"paypal_form\" ";
      echo "action=\"".$this->paypal_url."\">\n";

      foreach ($this->fields as $name => $value) {
         echo "<input type=\"hidden\" name=\"$name\" value=\"$value\"/>\n";
      }
        
      echo "</form>\n";
      echo "</body></html>\n";
    
   }
   
   function validate_ipn() {      

      # STEP 1: Read POST data

		# reading posted data from directly from $_POST causes serialization 
		# issues with array data in POST
		# reading raw POST data from input stream instead. 
		$raw_post_data = file_get_contents('php://input');
		$raw_post_array = explode('&', $raw_post_data);
		$myPost = array();
		foreach ($raw_post_array as $keyval) 
		{
		  $keyval = explode ('=', $keyval);
		  if (count($keyval) == 2)
			 $myPost[$keyval[0]] = urldecode($keyval[1]);
		}
		# read the post from PayPal system and add 'cmd'
		$req = 'cmd=_notify-validate';
		if(function_exists('get_magic_quotes_gpc')) 
		{
		   $get_magic_quotes_exists = true;
		} 
		foreach ($myPost as $key => $value) 
		{        
		   if($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) 
		   { 
				$value = urlencode(stripslashes($value)); 
		   } 
		   else 
		   {
				$value = urlencode($value);
		   }
		   $req .= "&$key=$value";
		}
		 
		 
		# STEP 2: Post IPN data back to paypal to validate
		 
		$ch = curl_init($this->paypal_url);
		curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
		curl_setopt($ch, CURLOPT_POST, 1);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
		curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
		curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
		curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
		curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
		curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
		 
		# In wamp like environments that do not come bundled with root authority certificates,
		# please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path 
		# of the certificate as shown below.
		# curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
		if( !($res = curl_exec($ch)) ) {
			curl_close($ch);
			$this->write_log('curl error');
			exit;
		}
		curl_close($ch);
		 
		
		# STEP 3: Inspect IPN validation result and act accordingly
		 
		if (strcmp ($res, "VERIFIED") == 0) 
		{
			return true;
			# assign posted variables to local variables
			#$uniqid 			= $_POST['custom'];
			#$item_number 		= $_POST['item_number'];
			#$payment_status 	= $_POST['payment_status'];
			#$payment_amount 	= $_POST['mc_gross'];
			#$payment_currency 	= $_POST['mc_currency'];
			#$txn_id 			= $_POST['txn_id'];
			#$txn_type 			= $_POST['txn_type'];
			#$receiver_email 	= $_POST['receiver_email'];
			#$payer_email 		= $_POST['payer_email'];
			# check whether the payment_status is Completed
			# check that txn_id has not been previously processed
			# check that receiver_email is your Primary PayPal email
			# check that payment_amount/payment_currency are correct

			
		}
		else if (strcmp ($res, "INVALID") == 0) 
		{ 
			return false;
		}
      
   }
   
   function log_ipn_results($success) {
       
      if (!$this->ipn_log) return;  // is logging turned off?
      
      // Timestamp
      $text = '['.date('m/d/Y g:i A').'] - '; 
      
      // Success or failure being logged?
      if ($success) $text .= "SUCCESS!\n";
      else $text .= 'FAIL: '.$this->last_error."\n";
      
      // Log the POST variables
      $text .= "IPN POST Vars from Paypal:\n";
      foreach ($this->ipn_data as $key=>$value) {
         $text .= "$key=$value, ";
      }
 
      // Log the response from the paypal server
      $text .= "\nIPN Response from Paypal Server:\n ".$this->ipn_response;
      
      // Write to log
      $fp=fopen($this->ipn_log_file,'a');
      fwrite($fp, $text . "\n\n"); 

      fclose($fp);  // close file
   }

   function dump_fields() {
 
      // Used for debugging, this function will output all the field/value pairs
      // that are currently defined in the instance of the class using the
      // add_field() function.
      
      echo "<h3>Paypal->dump_fields() Output:</h3>";
      echo "<table width=\"95%\" border=\"1\" cellpadding=\"2\" cellspacing=\"0\">
            <tr>
               <td bgcolor=\"black\"><b><font color=\"white\">Field Name</font></b></td>
               <td bgcolor=\"black\"><b><font color=\"white\">Value</font></b></td>
            </tr>"; 
      
      ksort($this->fields);
      foreach ($this->fields as $key => $value) {
         echo "<tr><td>$key</td><td>".urldecode($value)."&nbsp;</td></tr>";
      }
 
      echo "</table><br>"; 
   }
}