Networking Fundamentals - Project 1 Socket Programming

while True:

loops forever

for i in range(0, len(outputdata)): connectionSocket.send(outputdata[i].encode()) connectionSocket.send("\r\n".encode())

used to output all the data in the file all the content of the request file to client

TCP connection

a connection-oriented reliable protocol that uses a 3-way handshake

message = connectionSocket.recv(1024)

client program drops bytes in the string message into the TCP connection, client wait to receive bytes from server -> when characters arrives from the server they are placed in the string message

serverSocket.bind(('', serverPort))

used to associate the server port number, serverPort, with the socket Server socket = welcoming socket (door)

connectionSocket.close()

used to close this socket for the client

serverSocket = socket(AF_INET, SOCK_STREAM)

used to create a TCP socket

from socket import *

used to import socket module

f = open(filename[1:])

used to open the file

outputdata = f.read()

used to output the data and read the contents

filename = message.split()[1]

used to read the filename

connectionSocket.send('\nHTTP/1.1 200 OK\n\n')

used to send an 200 OK header line into the socket

except IOError: connectionSocket.send('\nHTTP/1.1 404 Not Found\n\n') print '404 Not Found'

used to send an error message to the page for a file that doesn't exist at the server

serverPort = 80

used to set the port for the server, browser will assume port 80 if port number is omitted

serverSocket.listen(1)

used to tell socket to wait and listen for client to "knock" on the door (request) -> parameter specifies max number of queued connections (1)

import sys

used to terminate the program

serverSocket.close() sys.exit()

used to terminate the program after sending the corresponding data

connectionSocket, addr = serverSocket.accept()

when client "knocks" on door, program invokes the accept() method for server socket -> creating a new socket in the server called connectionSocket dedicated to the particular client -> client and server complete handshaking creating TCP connection b/w client's clientSocket and server's connectionSocket