serve.py

from picamera import PiCamera
import logging
import ntplib
from time import ctime
import time
from datetime import datetime
import socket,datetime
# Define the IP address and the Port Number
ip      = "127.0.0.1";
port    = 7070;

camera = PiCamera()
camera.start_preview()
class NtpException(Exception):
    pass
def SyncClockToNtp():
  """Syncs the hardware clock to an NTP server."""
  server = 'europe.pool.ntp.org'
  retries = 2
  RETRY_DELAY=5
  logging.info('Reading time from NTP server %s.', server)

  attempts = 0
  client = ntplib.NTPClient()
  response = None

  while True:
    try:
      response = client.request(server, version=3)
    except (ntplib.NTPException, socket.gaierror) as e:
      logging.error('NTP client request error: %s', str(e))
    if response or attempts >= retries:
      break
    logging.info(
        'Unable to contact NTP server %s to sync machine clock.  This '
        'machine may not have an IP address yet; waiting %d seconds and '
        'trying again. Repeated failure may indicate network or driver '
        'problems.', server, RETRY_DELAY)
    time.sleep(RETRY_DELAY)
    attempts += 1

  if not response:
    raise NtpException('No response from NTP server.')

  now = time.clock_gettime(time.CLOCK_REALTIME)
  print("old time:",ctime(now))

  #print("Offset",response.offset)
  print("tx_time",ctime(response.tx_time))
  #print(response.tx_time)
  time.clock_settime(time.CLOCK_REALTIME, (response.tx_time))
  now = time.clock_gettime(time.CLOCK_REALTIME)
  print("Updated time:",ctime(now))


if __name__=='__main__':
    try:
        SyncClockToNtp()
    except NtpException:
        print("No response from NTP server. Please check your internet connection")
    listeningAddress = (ip, port)
    print("Listning on ",listeningAddress)
    # Create a datagram based server socket that uses IPv4 addressing scheme
    datagramSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    datagramSocket.bind(listeningAddress)
    try:
        while(True):
            tempVal, sourceAddress = datagramSocket.recvfrom(128)
            print("Time decided by %s is %s"%(sourceAddress, tempVal.decode()))
            response = "Received at: %s"%datetime.datetime.now()
            #print("Response: ",response)
            now = str(time.clock_gettime(time.CLOCK_REALTIME)+1)
            print(now)
            datagramSocket.sendto(response.encode(), sourceAddress)
            while now < tempVal.decode():
                now = str(time.clock_gettime(time.CLOCK_REALTIME)+1)
            print("Server takes picture at: ", now)
            camera.capture('/home/pi/Desktop/image%s.jpg' % ctime(datetime.datetime.now()))
    except keyboardInterrupt:
        print("Exiting Nicely")
        camera.stop_preview()