Create Calendar Events when I get parking receipt messages. Depends on receiving an email in the right format from the parking payment provider.

gistfile1.js

function processParkingMessages() {
  // get all unread messages labelled as Parking
  var parkingThreads = GmailApp.getUserLabelByName('Parking').getThreads();
  var parkingThreadMessages = parkingThreads.map(function(thread) { return thread.getMessages(); });
  var parkingMessages = [];
  var parkingMessages = parkingMessages.concat.apply(parkingMessages, parkingThreadMessages);
  var unreadParkingMessages = parkingMessages.filter(function(message) { return message.isUnread(); });
 
  // Map through all the unread parking messages and search for a date/time in the appropriate format.
  
  unreadParkingMessages.map(function(message) {
    // Stop Parking messages are in the following format
    // Stop Parking: 2015/02/15 3:04PM
    // /Stop\ Parking:\ (\d+)\/(\d+)\/(\d+)\ (\d+):(\d+)([AP]M)/
    
    var body = message.getBody();
    var res = body.match(/Stop\ Parking:\ (\d+)\/(\d+)\/(\d+)\ (\d+):(\d+)([AP]M)/);
    if (res) {
      var year = parseInt(res[1]);
      var month = parseInt(res[2]);
      var day = parseInt(res[3]);
      var hour = parseInt(res[4]);
      var minute = parseInt(res[5]);
      
      if (res[6] == 'PM') {
        hour+=12;
      }
      
      // Curse the person who decided the month was zero-indexed
      var startTime = new Date(year, month-1, day, hour, minute);

      Logger.log("Creating a Calendar Entry at "+ startTime);
      
      var event = CalendarApp.getDefaultCalendar().createEvent('Parking Expires',startTime,startTime);
      event.addPopupReminder(10);
      
      Logger.log('Event ID: ' + event.getId());
      Logger.log('Created at: ' + event.getStartTime());
      
      message.markRead();
    }
    
  });
}