ServerWorker.py

from random import randint
import sys, traceback, threading, socket

from VideoStream import VideoStream
from RtpPacket import RtpPacket

class ServerWorker:
	SETUP = 'SETUP'
	PLAY = 'PLAY'
	PAUSE = 'PAUSE'
	TEARDOWN = 'TEARDOWN'
	
	INIT = 0
	READY = 1
	PLAYING = 2
	state = INIT

	OK_200 = 0
	FILE_NOT_FOUND_404 = 1
	CON_ERR_500 = 2
	
	clientInfo = {}
	
	def __init__(self, clientInfo):
		self.clientInfo = clientInfo
		
	def run(self):
		threading.Thread(target=self.recvRtspRequest).start()
	
	def recvRtspRequest(self):
		"""Receive RTSP request from the client."""
		connSocket = self.clientInfo['rtspSocket'][0]
		while True:            
			data = connSocket.recv(256)
			if data:
				print "Data received:\n" + data
				self.processRtspRequest(data)
	
	def processRtspRequest(self, data):
		"""Process RTSP request sent from the client."""
	
		# Get the request type
		request = data.split('\n')
		line1 = request[0].split(' ')
		requestType = line1[0]
		
		# Get the media file name
		filename = line1[1]
		
		# Get the RTSP sequence number 
		seq = request[1].split(' ')
		
		# Process SETUP request
		if requestType == self.SETUP:
			if self.state == self.INIT:
				# Update state
				print "processing SETUP\n"
				
				try:
					self.clientInfo['videoStream'] = VideoStream(filename)
					self.state = self.READY
				except IOError:
					self.replyRtsp(self.FILE_NOT_FOUND_404, seq[1])
				
				# Generate a randomized RTSP session ID
				self.clientInfo['session'] = randint(100000, 999999)
				
				# Send RTSP reply
				self.replyRtsp(self.OK_200, seq[1])
				
				# Get the RTP/UDP port from the last line
				self.clientInfo['rtpPort'] = request[2].split(' ')[3]
		
		#--------------
		# TO COMPLETE
		#--------------
		# Process PLAY request
                # ...
		elif requestType == self.PLAY:
                        if self.state == self.READY:
                                print "processing PLAY\n"

                                self.state = self.PLAYING

                                self.clientInfo["rtpSocket"] = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
                                self.clientInfo['event'] = threading.Event()

                                self.replyRtsp(self.OK_200, seq[1])

                                threading.Thread(target=self.recvRtspRequest).start()

		# Process PAUSE request
                # ...
                elif requestType == self.PAUSE:
                        if self.state == self.PLAYING:
                                print "processing PAUSE\n"

                                self.state = self.READY

                                self.clientInfo['event'].set()

                                self.replyRtsp(self.OK_200, seq[1])
	
		# Process TEARDOWN request
		elif requestType == self.TEARDOWN:
                        print "processing TEARDOWN\n"

                        self.clientInfo['event'].set()

                        self.replyRtsp(self.OK_200, seq[1])

                        self.clientInfo['rtpSocket'].close()
			
	def sendRtp(self):
		"""Send RTP packets over UDP."""
		while True:
			self.clientInfo['event'].wait(0.05) 
			
			# Stop sending if request is PAUSE or TEARDOWN
			if self.clientInfo['event'].isSet(): 
				break 
				
			data = self.clientInfo['videoStream'].nextFrame()
			if data: 
				frameNumber = self.clientInfo['videoStream'].frameNbr()
				try:
					address = self.clientInfo['rtspSocket'][1][0]
					port = int(self.clientInfo['rtpPort'])
					self.clientInfo['rtpSocket'].sendto(self.makeRtp(data, frameNumber),(address,port))
				except:
					print "Connection Error"

	def makeRtp(self, payload, frameNbr):
		"""RTP-packetize the video data."""
		#-------------
		# TO COMPLETE
		#-------------
                # Set the fields
		# ...
		V = 2
		P = 0
		X = 0
		CC = 0
		M = 0
		PT = 26
		seqNum = frameNbr
		SSRC = 0

                # Create and encode the RTP packet	
	        # ...	
                rtpPacket = RtpPacket()
                rtpPacket.encode(V, P, X, CC, seqNum, M, PT, SSRC, payload)

                # Return the RTP packet
	        # ...
	        return rtpPacket.getPacket()
		
	def replyRtsp(self, code, seq):
		"""Send RTSP reply to the client."""
		if code == self.OK_200:
			#print "200 OK"
			reply = 'RTSP/1.0 200 OK\nCSeq: ' + seq + '\nSession: ' + str(self.clientInfo['session'])
			connSocket = self.clientInfo['rtspSocket'][0]
			connSocket.send(reply)
		
		# Error messages
		elif code == self.FILE_NOT_FOUND_404:
			print "404 NOT FOUND"
		elif code == self.CON_ERR_500:
			print "500 CONNECTION ERROR"