tps_vehiclepos_process_feed.py

def process_feed(feed, today):
  global dict_pushpinLabel_to_desc_map
  global dict_vehicleId_to_pushpinLabel_map
  global lastpushpinLabel
  global pushpin_url
  global total_vehicles_found

  #we will use the python module 'time' to convert epoch time (this is what gtfsr timestamps are in) to local time
  #set the timezone for time
  os.environ['TZ'] = 'AEST-10AEDT-11,M10.5.0,M3.5.0'
  time.tzset()
  print(f'timezone set to {time.tzname}')

  num_pushpin_assigned = 0
  total_feed_entity = len(feed.entity)
  total_vehicles_found += total_feed_entity
  print('Total feed.entity:',total_feed_entity," Total Vehicles Found:",total_vehicles_found)
  
  #As we are using Bing maps, there is a limit to the number of pushpins we can specify for our map. If we
  #reach this limit, we will break out of the loop below as there is no benefit for continuing on processing
  for entity in feed.entity:
    if num_pushpin_assigned >= maps_bing_pushpin_limit:
      break #we haev exceeded the number of pushpins that can be used with Bing Maps. Exit loop
    
    tripupdatetimestamp_autz = time.ctime(entity.vehicle.timestamp)
    vehicleId = entity.vehicle.vehicle.id

    #we need to make sure that the fields used for dynamodb keys are not null. If they are then skip this record. Currently these are TripDate which is
    #todays date and vehicleId. So just check vehicleId for being not null and TripDate won't be null.
    if (vehicleId): #only go ahead if vehicleId is present. Otherwise just print that vehicleId for this record is missing
      #lets find out if this vehicle already has a pushpinLabel assigned for today
      if vehicleId in dict_vehicleId_to_pushpinLabel_map.keys():
        #this vehicle already has a pushpinLabel. Get the label
        pushpinLabel = dict_vehicleId_to_pushpinLabel_map[vehicleId]['label']
      else:
        #this vehicle doesn't have any pushpinLabel already assigned. Generate a new pushpinLabel for it
        lastpushpinLabel += 1  #increment the lastpushpinLabel so that it now points to a new number
        pushpinLabel = lastpushpinLabel

        tripId = entity.vehicle.trip.trip_id
        #the pushpinLabelDesc will be set to the vehicle's label. There have been instances where I noticed the vehicle's label is missing/null.
        #In these cases, set the pushpinLabelDesc to TripId
        if not entity.vehicle.vehicle.label:
          pushpinLabelDesc = tripId
        else:
          pushpinLabelDesc = entity.vehicle.vehicle.label
        
        #since this vehicle had not been previously assigned a pushpinLabel for today, add its details to the two dict
        inDynamodbTable = False #this item has not been read from or written to dynamodb yet
        latitude = entity.vehicle.position.latitude
        longitude = entity.vehicle.position.longitude
  
        dict_pushpinLabel_to_desc_map[str(pushpinLabel)] = {"desc": str(pushpinLabelDesc),"vehicleId": str(vehicleId),"inDynamodbTable":inDynamodbTable,"latitude":latitude,"longitude":longitude,"tripId":tripId}
        dict_vehicleId_to_pushpinLabel_map[str(vehicleId)] = {"label": str(pushpinLabel), "desc": str(pushpinLabelDesc)}    
      
      #this vehicle will be displayed on the map. Update dict_pushpinLabel_to_desc_map for this vehicle's entry so that when the legend is 
      #generated, it will be coloured differently to show that it is currently displayed on the map
      dict_pushpinLabel_to_desc_map[str(pushpinLabel)]['isDisplayedOnMap'] = True

      #add this vehicle's details to the pushpin url
      pushpin_url += "pp=" + str(entity.vehicle.position.latitude) + "," + str(entity.vehicle.position.longitude)
      #based on how long ago the laststopid timestamp is, calculate if the vehicle is active or inactive and respectively assign the icon
      if (datetime.datetime.now() - datetime.datetime.strptime(tripupdatetimestamp_autz,'%a %b %d %H:%M:%S %Y')) > datetime.timedelta(minutes=inactive_vehicle_datetime_limit):
        #this vehicle is inactive
        pushpin_url += ";" + maps_inactive_vehicle_icon + ";"
      else:
        pushpin_url += ";" + maps_active_vehicle_icon + ";"

      pushpin_url += str(pushpinLabel) + "&"
      num_pushpin_assigned += 1 #increment the counter that denotes the number of pushpins added to the pushpin url
    else:
      print("process_feed:MissingVehicleId:VehicleWillBeSkipped:TripId:", entity.vehicle.trip.trip_id, " VehicleLabel:", entity.vehicle.vehicle.label," Latitude: ", entity.vehicle.position.latitude, " Longitude: ", entity.vehicle.position.longitude)