UDP_Server.py

import binascii
import socket
import struct
import sys
import hashlib
import select
import codecs
import threading
import time
from hurry.filesize import size

fileUpdate = threading.Event()
endLoop = threading.Event()
repeatRecv = threading.Event()

UDP_IP = "0.0.0.0"
UDP_PORT = 5005
UDP_PORT2 = 5002
Client_IP = "127.0.0.1"
bytesCount = 1024 * 63
maxThreads = 1
fileName = "out_CS3543_100MB"
if len(sys.argv) == 2:
    Client_IP = sys.argv[1]
if len(sys.argv) >= 3:
    fileName = sys.argv[2]
endMessage = b"complete"
out_file = open(fileName, "wb")

unpacker = struct.Struct("I I " + str(bytesCount) + "s 32s")
packer = struct.Struct("I I " + str(bytesCount) + "s")

# Create the socket and listen
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)  # ACK
sock2 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)  # Data Packets

sock.bind((UDP_IP, UDP_PORT))

end = 0
x = 0
writeCount = 0
Timeout = 0.03

# Queue to store pending packets
class Queue:
    def __init__(self):
        self.queue = list()

    def addtoq(self, dataval):
        self.queue.insert(0, dataval)
        repeatRecv.set()
        return True

    def size(self):
        return len(self.queue)

    def removefromq(self):
        if len(self.queue) == 0:
            return (0, 0)
        return self.queue.pop()


dataQueue = Queue()


def writeData(count, data):
    global writeCount
    if writeCount > count:
        return
    while count != writeCount:
        fileUpdate.wait()

    fileUpdate.clear()
    out_file.write(data)
    writeCount = writeCount + 1
    # print("Wrote: ",size(count*bytesCount))
    fileUpdate.set()
    return


def closeFile(count):
    if writeCount > count:
        return
    while count != writeCount:
        fileUpdate.wait()
    endLoop.set()
    repeatRecv.set()
    out_file.close()
    print("File closed")


def receive_data():
    while True:
        newData = dataQueue.removefromq()
        if newData[0] != 0:
            UDP_Packet = unpacker.unpack(newData[0])
            # print("received from:", addr)
            # print("received message:", UDP_Packet)

            # Create the Checksum for comparison
            values = (UDP_Packet[0], UDP_Packet[1], UDP_Packet[2])
            packed_data = packer.pack(*values)
            chksum = bytes(hashlib.md5(packed_data).hexdigest(), encoding="UTF-8")

            # Compare Checksums to test for corrupt data
            if UDP_Packet[3] == chksum and UDP_Packet[1] == UDP_Packet[0] % 2:
                # Send Packet through
                sock2.sendto(newData[0], (Client_IP, UDP_PORT2))
                offset = removeNullBytes(UDP_Packet[2])
                if UDP_Packet[2][:offset] == endMessage:
                    closeFile(UDP_Packet[0])
                else:
                    writeData(UDP_Packet[0], UDP_Packet[2][:offset])
            else:

                print(
                    "CheckSums do not Match or the Sequence Number is incorrect, Packet is not ok"
                )
                sock2.sendto(newData[0], (Client_IP, UDP_PORT2))
        else:
            if endLoop.is_set() == True:
                return
            else:
                repeatRecv.wait()


def removeNullBytes(input):
    offset = bytesCount
    i = offset - 1
    while i > -1:
        if input[i] == 0:
            offset = offset - 1
            i = i - 1
        else:
            break
    return offset


repeatRecv.clear()

while maxThreads > 0 and endLoop.is_set() == False:
    print("Packet Number: " + str(x+1))
    timer = select.select([sock], [], [], Timeout)
    if timer[0]:
        maxThreads = maxThreads - 1
        data, addr = sock.recvfrom(bytesCount + 1024)
        dataQueue.addtoq((data, addr))
        repeatRecv.clear()
        thread = threading.Thread(target=receive_data)
        thread.start()
        x = x + 1

while endLoop.is_set() == False:
    print("Packet Number: " + str(x + 1))
    timer = select.select([sock], [], [], Timeout)
    if timer[0]:
        data, addr = sock.recvfrom(bytesCount + 1024)
        dataQueue.addtoq((data, addr))
        repeatRecv.clear()
        x = x + 1