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   1  <?php  // $Id: ipn.php,v 1.22 2007/10/09 12:49:57 skodak Exp $
   2  
   3  /**
   4  * Listens for Instant Payment Notification from PayPal
   5  *
   6  * This script waits for Payment notification from PayPal,
   7  * then double checks that data by sending it back to PayPal.
   8  * If PayPal verifies this then it sets up the enrolment for that
   9  *
  10  * Set the $user->timeaccess course array
  11  *
  12  * @param    user  referenced object, must contain $user->id already set
  13  */
  14  
  15  
  16      require("../../config.php");
  17      require ("enrol.php");
  18  
  19  /// Keep out casual intruders
  20      if (empty($_POST) or !empty($_GET)) {
  21          error("Sorry, you can not use the script that way.");
  22      }
  23  
  24  /// Read all the data from PayPal and get it ready for later;
  25  /// we expect only valid UTF-8 encoding, it is the responsibility
  26  /// of user to set it up properly in PayPal business acount,
  27  /// it is documented in docs wiki.
  28  
  29      $req = 'cmd=_notify-validate';
  30  
  31      $data = new object();
  32  
  33      foreach ($_POST as $key => $value) {
  34          $value = stripslashes($value);
  35          $req .= "&$key=".urlencode($value);
  36          $data->$key = $value;
  37      }
  38  
  39      $custom = explode('-', $data->custom);
  40      $data->userid           = (int)$custom[0];
  41      $data->courseid         = (int)$custom[1];
  42      $data->payment_gross    = $data->mc_gross;
  43      $data->payment_currency = $data->mc_currency;
  44      $data->timeupdated      = time();
  45  
  46  
  47  /// get the user and course records
  48  
  49      if (! $user = get_record("user", "id", $data->userid) ) {
  50          email_paypal_error_to_admin("Not a valid user id", $data);
  51          die;
  52      }
  53  
  54      if (! $course = get_record("course", "id", $data->courseid) ) {
  55          email_paypal_error_to_admin("Not a valid course id", $data);
  56          die;
  57      }
  58  
  59      if (! $context = get_context_instance(CONTEXT_COURSE, $course->id)) {
  60          email_paypal_error_to_admin("Not a valid context id", $data);
  61          die;
  62      }
  63  
  64  /// Open a connection back to PayPal to validate the data
  65  
  66      $header = '';
  67      $header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";
  68      $header .= "Content-Type: application/x-www-form-urlencoded\r\n";
  69      $header .= "Content-Length: " . strlen($req) . "\r\n\r\n";
  70      $paypaladdr = empty($CFG->usepaypalsandbox) ? 'www.paypal.com' : 'www.sandbox.paypal.com';
  71      $fp = fsockopen ($paypaladdr, 80, $errno, $errstr, 30);
  72  
  73      if (!$fp) {  /// Could not open a socket to PayPal - FAIL
  74          echo "<p>Error: could not access paypal.com</p>";
  75          email_paypal_error_to_admin("Could not access paypal.com to verify payment", $data);
  76          die;
  77      }
  78  
  79  /// Connection is OK, so now we post the data to validate it
  80  
  81      fputs ($fp, $header.$req);
  82  
  83  /// Now read the response and check if everything is OK.
  84  
  85      while (!feof($fp)) {
  86          $result = fgets($fp, 1024);
  87          if (strcmp($result, "VERIFIED") == 0) {          // VALID PAYMENT!
  88  
  89  
  90              // check the payment_status and payment_reason
  91  
  92              // If status is not completed or pending then unenrol the student if already enrolled
  93              // and notify admin
  94  
  95              if ($data->payment_status != "Completed" and $data->payment_status != "Pending") {
  96                  role_unassign(0, $data->userid, 0, $context->id);
  97                  email_paypal_error_to_admin("Status not completed or pending. User unenrolled from course", $data);
  98                  die;
  99              }
 100  
 101              // If status is pending and reason is other than echeck then we are on hold until further notice
 102              // Email user to let them know. Email admin.
 103  
 104              if ($data->payment_status == "Pending" and $data->pending_reason != "echeck") {
 105                  email_to_user($user, get_admin(), "Moodle: PayPal payment", "Your PayPal payment is pending.");
 106                  email_paypal_error_to_admin("Payment pending", $data);
 107                  die;
 108              }
 109  
 110              // If our status is not completed or not pending on an echeck clearance then ignore and die
 111              // This check is redundant at present but may be useful if paypal extend the return codes in the future
 112  
 113              if (! ( $data->payment_status == "Completed" or
 114                     ($data->payment_status == "Pending" and $data->pending_reason == "echeck") ) ) {
 115                  die;
 116              }
 117  
 118              // At this point we only proceed with a status of completed or pending with a reason of echeck
 119  
 120  
 121  
 122              if ($existing = get_record("enrol_paypal", "txn_id", addslashes($data->txn_id))) {   // Make sure this transaction doesn't exist already
 123                  email_paypal_error_to_admin("Transaction $data->txn_id is being repeated!", $data);
 124                  die;
 125  
 126              }
 127  
 128              if ($data->business != $CFG->enrol_paypalbusiness) {   // Check that the email is the one we want it to be
 129                  email_paypal_error_to_admin("Business email is $data->business (not $CFG->enrol_paypalbusiness)", $data);
 130                  die;
 131  
 132              }
 133  
 134              if (!$user = get_record('user', 'id', $data->userid)) {   // Check that user exists
 135                  email_paypal_error_to_admin("User $data->userid doesn't exist", $data);
 136                  die;
 137              }
 138  
 139              if (!$course = get_record('course', 'id', $data->courseid)) { // Check that course exists
 140                  email_paypal_error_to_admin("Course $data->courseid doesn't exist", $data);;
 141                  die;
 142              }
 143  
 144              // Check that amount paid is the correct amount
 145              if ( (float) $course->cost < 0 ) {
 146                  $cost = (float) $CFG->enrol_cost;
 147              } else {
 148                  $cost = (float) $course->cost;
 149              }
 150  
 151              if ($data->payment_gross < $cost) {
 152                  $cost = format_float($cost, 2);
 153                  email_paypal_error_to_admin("Amount paid is not enough ($data->payment_gross < $cost))", $data);
 154                  die;
 155  
 156              }
 157  
 158              // ALL CLEAR !
 159  
 160              if (!insert_record("enrol_paypal", addslashes_object($data))) {       // Insert a transaction record
 161                  email_paypal_error_to_admin("Error while trying to insert valid transaction", $data);
 162              }
 163  
 164              if (!enrol_into_course($course, $user, 'paypal')) {
 165                  email_paypal_error_to_admin("Error while trying to enrol ".fullname($user)." in '$course->fullname'", $data);
 166                  die;
 167              } else {
 168                  $teacher = get_teacher($course->id);
 169  
 170                  if (!empty($CFG->enrol_mailstudents)) {
 171                      $a->coursename = $course->fullname;
 172                      $a->profileurl = "$CFG->wwwroot/user/view.php?id=$user->id";
 173                      email_to_user($user, $teacher, get_string("enrolmentnew", '', $course->shortname),
 174                                    get_string('welcometocoursetext', '', $a));
 175                  }
 176  
 177                  if (!empty($CFG->enrol_mailteachers)) {
 178                      $a->course = $course->fullname;
 179                      $a->user = fullname($user);
 180                      email_to_user($teacher, $user, get_string("enrolmentnew", '', $course->shortname),
 181                                    get_string('enrolmentnewuser', '', $a));
 182                  }
 183  
 184                  if (!empty($CFG->enrol_mailadmins)) {
 185                      $a->course = $course->fullname;
 186                      $a->user = fullname($user);
 187                      $admins = get_admins();
 188                      foreach ($admins as $admin) {
 189                          email_to_user($admin, $user, get_string("enrolmentnew", '', $course->shortname),
 190                                        get_string('enrolmentnewuser', '', $a));
 191                      }
 192                  }
 193  
 194              }
 195  
 196  
 197          } else if (strcmp ($result, "INVALID") == 0) { // ERROR
 198              insert_record("enrol_paypal", addslashes_object($data), false);
 199              email_paypal_error_to_admin("Received an invalid payment notification!! (Fake payment?)", $data);
 200          }
 201      }
 202  
 203      fclose($fp);
 204      exit;
 205  
 206  
 207  
 208  /// FUNCTIONS //////////////////////////////////////////////////////////////////
 209  
 210  
 211  function email_paypal_error_to_admin($subject, $data) {
 212      $admin = get_admin();
 213      $site = get_site();
 214  
 215      $message = "$site->fullname:  Transaction failed.\n\n$subject\n\n";
 216  
 217      foreach ($data as $key => $value) {
 218          $message .= "$key => $value\n";
 219      }
 220  
 221      email_to_user($admin, $admin, "PAYPAL ERROR: ".$subject, $message);
 222  
 223  }
 224  
 225  ?>