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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Listens for Instant Payment Notification from PayPal
  19   *
  20   * This script waits for Payment notification from PayPal,
  21   * then double checks that data by sending it back to PayPal.
  22   * If PayPal verifies this then it sets up the enrolment for that
  23   * user.
  24   *
  25   * @package    enrol_paypal
  26   * @copyright 2010 Eugene Venter
  27   * @author     Eugene Venter - based on code by others
  28   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  29   */
  30  
  31  // Disable moodle specific debug messages and any errors in output,
  32  // comment out when debugging or better look into error log!
  33  define('NO_DEBUG_DISPLAY', true);
  34  
  35  require("../../config.php");
  36  require_once ("lib.php");
  37  require_once($CFG->libdir.'/eventslib.php');
  38  require_once($CFG->libdir.'/enrollib.php');
  39  require_once($CFG->libdir . '/filelib.php');
  40  
  41  // PayPal does not like when we return error messages here,
  42  // the custom handler just logs exceptions and stops.
  43  set_exception_handler('enrol_paypal_ipn_exception_handler');
  44  
  45  /// Keep out casual intruders
  46  if (empty($_POST) or !empty($_GET)) {
  47      print_error("Sorry, you can not use the script that way.");
  48  }
  49  
  50  /// Read all the data from PayPal and get it ready for later;
  51  /// we expect only valid UTF-8 encoding, it is the responsibility
  52  /// of user to set it up properly in PayPal business account,
  53  /// it is documented in docs wiki.
  54  
  55  $req = 'cmd=_notify-validate';
  56  
  57  $data = new stdClass();
  58  
  59  foreach ($_POST as $key => $value) {
  60      $req .= "&$key=".urlencode($value);
  61      $data->$key = $value;
  62  }
  63  
  64  $custom = explode('-', $data->custom);
  65  $data->userid           = (int)$custom[0];
  66  $data->courseid         = (int)$custom[1];
  67  $data->instanceid       = (int)$custom[2];
  68  $data->payment_gross    = $data->mc_gross;
  69  $data->payment_currency = $data->mc_currency;
  70  $data->timeupdated      = time();
  71  
  72  
  73  /// get the user and course records
  74  
  75  if (! $user = $DB->get_record("user", array("id"=>$data->userid))) {
  76      message_paypal_error_to_admin("Not a valid user id", $data);
  77      die;
  78  }
  79  
  80  if (! $course = $DB->get_record("course", array("id"=>$data->courseid))) {
  81      message_paypal_error_to_admin("Not a valid course id", $data);
  82      die;
  83  }
  84  
  85  if (! $context = context_course::instance($course->id, IGNORE_MISSING)) {
  86      message_paypal_error_to_admin("Not a valid context id", $data);
  87      die;
  88  }
  89  
  90  if (! $plugin_instance = $DB->get_record("enrol", array("id"=>$data->instanceid, "status"=>0))) {
  91      message_paypal_error_to_admin("Not a valid instance id", $data);
  92      die;
  93  }
  94  
  95  $plugin = enrol_get_plugin('paypal');
  96  
  97  /// Open a connection back to PayPal to validate the data
  98  $paypaladdr = empty($CFG->usepaypalsandbox) ? 'www.paypal.com' : 'www.sandbox.paypal.com';
  99  $c = new curl();
 100  $options = array(
 101      'returntransfer' => true,
 102      'httpheader' => array('application/x-www-form-urlencoded', "Host: $paypaladdr"),
 103      'timeout' => 30,
 104      'CURLOPT_HTTP_VERSION' => CURL_HTTP_VERSION_1_1,
 105  );
 106  $location = "https://$paypaladdr/cgi-bin/webscr";
 107  $result = $c->post($location, $req, $options);
 108  
 109  if (!$result) {  /// Could not connect to PayPal - FAIL
 110      echo "<p>Error: could not access paypal.com</p>";
 111      message_paypal_error_to_admin("Could not access paypal.com to verify payment", $data);
 112      die;
 113  }
 114  
 115  /// Connection is OK, so now we post the data to validate it
 116  
 117  /// Now read the response and check if everything is OK.
 118  
 119  if (strlen($result) > 0) {
 120      if (strcmp($result, "VERIFIED") == 0) {          // VALID PAYMENT!
 121  
 122  
 123          // check the payment_status and payment_reason
 124  
 125          // If status is not completed or pending then unenrol the student if already enrolled
 126          // and notify admin
 127  
 128          if ($data->payment_status != "Completed" and $data->payment_status != "Pending") {
 129              $plugin->unenrol_user($plugin_instance, $data->userid);
 130              message_paypal_error_to_admin("Status not completed or pending. User unenrolled from course", $data);
 131              die;
 132          }
 133  
 134          // If currency is incorrectly set then someone maybe trying to cheat the system
 135  
 136          if ($data->mc_currency != $plugin_instance->currency) {
 137              message_paypal_error_to_admin("Currency does not match course settings, received: ".$data->mc_currency, $data);
 138              die;
 139          }
 140  
 141          // If status is pending and reason is other than echeck then we are on hold until further notice
 142          // Email user to let them know. Email admin.
 143  
 144          if ($data->payment_status == "Pending" and $data->pending_reason != "echeck") {
 145              $eventdata = new stdClass();
 146              $eventdata->modulename        = 'moodle';
 147              $eventdata->component         = 'enrol_paypal';
 148              $eventdata->name              = 'paypal_enrolment';
 149              $eventdata->userfrom          = get_admin();
 150              $eventdata->userto            = $user;
 151              $eventdata->subject           = "Moodle: PayPal payment";
 152              $eventdata->fullmessage       = "Your PayPal payment is pending.";
 153              $eventdata->fullmessageformat = FORMAT_PLAIN;
 154              $eventdata->fullmessagehtml   = '';
 155              $eventdata->smallmessage      = '';
 156              message_send($eventdata);
 157  
 158              message_paypal_error_to_admin("Payment pending", $data);
 159              die;
 160          }
 161  
 162          // If our status is not completed or not pending on an echeck clearance then ignore and die
 163          // This check is redundant at present but may be useful if paypal extend the return codes in the future
 164  
 165          if (! ( $data->payment_status == "Completed" or
 166                 ($data->payment_status == "Pending" and $data->pending_reason == "echeck") ) ) {
 167              die;
 168          }
 169  
 170          // At this point we only proceed with a status of completed or pending with a reason of echeck
 171  
 172  
 173  
 174          if ($existing = $DB->get_record("enrol_paypal", array("txn_id"=>$data->txn_id))) {   // Make sure this transaction doesn't exist already
 175              message_paypal_error_to_admin("Transaction $data->txn_id is being repeated!", $data);
 176              die;
 177  
 178          }
 179  
 180          if (core_text::strtolower($data->business) !== core_text::strtolower($plugin->get_config('paypalbusiness'))) {   // Check that the email is the one we want it to be
 181              message_paypal_error_to_admin("Business email is {$data->business} (not ".
 182                      $plugin->get_config('paypalbusiness').")", $data);
 183              die;
 184  
 185          }
 186  
 187          if (!$user = $DB->get_record('user', array('id'=>$data->userid))) {   // Check that user exists
 188              message_paypal_error_to_admin("User $data->userid doesn't exist", $data);
 189              die;
 190          }
 191  
 192          if (!$course = $DB->get_record('course', array('id'=>$data->courseid))) { // Check that course exists
 193              message_paypal_error_to_admin("Course $data->courseid doesn't exist", $data);
 194              die;
 195          }
 196  
 197          $coursecontext = context_course::instance($course->id, IGNORE_MISSING);
 198  
 199          // Check that amount paid is the correct amount
 200          if ( (float) $plugin_instance->cost <= 0 ) {
 201              $cost = (float) $plugin->get_config('cost');
 202          } else {
 203              $cost = (float) $plugin_instance->cost;
 204          }
 205  
 206          // Use the same rounding of floats as on the enrol form.
 207          $cost = format_float($cost, 2, false);
 208  
 209          if ($data->payment_gross < $cost) {
 210              message_paypal_error_to_admin("Amount paid is not enough ($data->payment_gross < $cost))", $data);
 211              die;
 212  
 213          }
 214  
 215          // ALL CLEAR !
 216  
 217          $DB->insert_record("enrol_paypal", $data);
 218  
 219          if ($plugin_instance->enrolperiod) {
 220              $timestart = time();
 221              $timeend   = $timestart + $plugin_instance->enrolperiod;
 222          } else {
 223              $timestart = 0;
 224              $timeend   = 0;
 225          }
 226  
 227          // Enrol user
 228          $plugin->enrol_user($plugin_instance, $user->id, $plugin_instance->roleid, $timestart, $timeend);
 229  
 230          // Pass $view=true to filter hidden caps if the user cannot see them
 231          if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC',
 232                                               '', '', '', '', false, true)) {
 233              $users = sort_by_roleassignment_authority($users, $context);
 234              $teacher = array_shift($users);
 235          } else {
 236              $teacher = false;
 237          }
 238  
 239          $mailstudents = $plugin->get_config('mailstudents');
 240          $mailteachers = $plugin->get_config('mailteachers');
 241          $mailadmins   = $plugin->get_config('mailadmins');
 242          $shortname = format_string($course->shortname, true, array('context' => $context));
 243  
 244  
 245          if (!empty($mailstudents)) {
 246              $a = new stdClass();
 247              $a->coursename = format_string($course->fullname, true, array('context' => $coursecontext));
 248              $a->profileurl = "$CFG->wwwroot/user/view.php?id=$user->id";
 249  
 250              $eventdata = new stdClass();
 251              $eventdata->modulename        = 'moodle';
 252              $eventdata->component         = 'enrol_paypal';
 253              $eventdata->name              = 'paypal_enrolment';
 254              $eventdata->userfrom          = empty($teacher) ? get_admin() : $teacher;
 255              $eventdata->userto            = $user;
 256              $eventdata->subject           = get_string("enrolmentnew", 'enrol', $shortname);
 257              $eventdata->fullmessage       = get_string('welcometocoursetext', '', $a);
 258              $eventdata->fullmessageformat = FORMAT_PLAIN;
 259              $eventdata->fullmessagehtml   = '';
 260              $eventdata->smallmessage      = '';
 261              message_send($eventdata);
 262  
 263          }
 264  
 265          if (!empty($mailteachers) && !empty($teacher)) {
 266              $a->course = format_string($course->fullname, true, array('context' => $coursecontext));
 267              $a->user = fullname($user);
 268  
 269              $eventdata = new stdClass();
 270              $eventdata->modulename        = 'moodle';
 271              $eventdata->component         = 'enrol_paypal';
 272              $eventdata->name              = 'paypal_enrolment';
 273              $eventdata->userfrom          = $user;
 274              $eventdata->userto            = $teacher;
 275              $eventdata->subject           = get_string("enrolmentnew", 'enrol', $shortname);
 276              $eventdata->fullmessage       = get_string('enrolmentnewuser', 'enrol', $a);
 277              $eventdata->fullmessageformat = FORMAT_PLAIN;
 278              $eventdata->fullmessagehtml   = '';
 279              $eventdata->smallmessage      = '';
 280              message_send($eventdata);
 281          }
 282  
 283          if (!empty($mailadmins)) {
 284              $a->course = format_string($course->fullname, true, array('context' => $coursecontext));
 285              $a->user = fullname($user);
 286              $admins = get_admins();
 287              foreach ($admins as $admin) {
 288                  $eventdata = new stdClass();
 289                  $eventdata->modulename        = 'moodle';
 290                  $eventdata->component         = 'enrol_paypal';
 291                  $eventdata->name              = 'paypal_enrolment';
 292                  $eventdata->userfrom          = $user;
 293                  $eventdata->userto            = $admin;
 294                  $eventdata->subject           = get_string("enrolmentnew", 'enrol', $shortname);
 295                  $eventdata->fullmessage       = get_string('enrolmentnewuser', 'enrol', $a);
 296                  $eventdata->fullmessageformat = FORMAT_PLAIN;
 297                  $eventdata->fullmessagehtml   = '';
 298                  $eventdata->smallmessage      = '';
 299                  message_send($eventdata);
 300              }
 301          }
 302  
 303      } else if (strcmp ($result, "INVALID") == 0) { // ERROR
 304          $DB->insert_record("enrol_paypal", $data, false);
 305          message_paypal_error_to_admin("Received an invalid payment notification!! (Fake payment?)", $data);
 306      }
 307  }
 308  
 309  exit;
 310  
 311  
 312  //--- HELPER FUNCTIONS --------------------------------------------------------------------------------------
 313  
 314  
 315  function message_paypal_error_to_admin($subject, $data) {
 316      echo $subject;
 317      $admin = get_admin();
 318      $site = get_site();
 319  
 320      $message = "$site->fullname:  Transaction failed.\n\n$subject\n\n";
 321  
 322      foreach ($data as $key => $value) {
 323          $message .= "$key => $value\n";
 324      }
 325  
 326      $eventdata = new stdClass();
 327      $eventdata->modulename        = 'moodle';
 328      $eventdata->component         = 'enrol_paypal';
 329      $eventdata->name              = 'paypal_enrolment';
 330      $eventdata->userfrom          = $admin;
 331      $eventdata->userto            = $admin;
 332      $eventdata->subject           = "PAYPAL ERROR: ".$subject;
 333      $eventdata->fullmessage       = $message;
 334      $eventdata->fullmessageformat = FORMAT_PLAIN;
 335      $eventdata->fullmessagehtml   = '';
 336      $eventdata->smallmessage      = '';
 337      message_send($eventdata);
 338  }
 339  
 340  /**
 341   * Silent exception handler.
 342   *
 343   * @param Exception $ex
 344   * @return void - does not return. Terminates execution!
 345   */
 346  function enrol_paypal_ipn_exception_handler($ex) {
 347      $info = get_exception_info($ex);
 348  
 349      $logerrmsg = "enrol_paypal IPN exception handler: ".$info->message;
 350      if (debugging('', DEBUG_NORMAL)) {
 351          $logerrmsg .= ' Debug: '.$info->debuginfo."\n".format_backtrace($info->backtrace, true);
 352      }
 353      error_log($logerrmsg);
 354  
 355      exit(0);
 356  }