Lab 2: Web Server Lab   In this lab, you will learn the basics of socket programming for TCP connections in Python: how to create a socket, bind it to a specific address and port, and send and receive a HTTP packet. You will also learn some basics of HTTP header format.   You will develop a web server that handles one HTTP request at a time. Your web server should accept and parse the HTTP request, get the requested file from the server’s file system, create an HTTP response message consisting of the requested file preceded by header lines, and send the response directly to the client. If the requested file is not present in the server, the server should send an HTTP “404 Not Found” message back to the client.   Code Below you will find the skeleton code for the Web server. You are to complete the skeleton code. The places where you need to fill in code are marked with #Fill in start and #Fill in end. Each place may require one or more lines of code.   Running the Server Put an HTML file (e.g., helloworld.html) in the same directory that the server is in. Run the server program. Determine the IP address of the host that is running the server (e.g., 127.0.0.1). Open a browser and provide the corresponding URL. For example: http://127.0.0.1:13331/helloworld.html   ‘helloworld.html’ is the name of the file you placed in the server directory. Note also the use of the port number after the colon. GradeScope will test your code using port 13331. In the above example, we have used the port number 13331. The browser should then display the contents of helloworld.html. If you omit ":13331", the browser will assume port 80 and you will get the web page from the server only if your server is listening at port 80. Next, try to get a file that is not present at the server. You should get a “404 Not Found” message.   What to Hand in Submit the code to GradeScope (include helloworld.html if it exists) using your GitHub repository. Program file name must be solution.py.   Notes: There are clients (browsers) that will not present HTML content unless encoded HTTP headers are submitted with the message from the web server. HTTP status codes “200 OK” and “404 Not Found” are required to be part of the Web Server in order to receive full credit on this assignment.   Skeleton Code Code is available below and on Google Drive: https://drive.google.com/file/d/1_9O4p68nlK6a5XC5haOZ5OVTinuF_7cu/view?usp=sharing   Skeleton Python Code for the Web Server  #import socket module from socket import * import sys # In order to terminate the program   def webServer(port=13331):    serverSocket = socket(AF_INET, SOCK_STREAM)      #Prepare a server socket    #Fill in start      #Fill in end      while True:        #Establish the connection        print('Ready to serve...')        connectionSocket, addr = #Fill in start      #Fill in end        try:            message = #Fill in start    #Fill in end            filename = message.split()[1]            f = open(filename[1:])            outputdata = #Fill in start     #Fill in end              #Send one HTTP header line into socket            #Fill in start              #Fill in end              #Send the content of the requested file to the client            for i in range(0, len(outputdata)):                connectionSocket.send(outputdata[i].encode())              connectionSocket.send("\r\n".encode())            connectionSocket.close()        except IOError:            #Send response message for file not found (404)            #Fill in start              #Fill in end              #Close client socket            #Fill in start              #Fill in end      serverSocket.close()    sys.exit()  # Terminate the program after sending the corresponding data   if __name__ == "__main__":    webServer(13331)

Computer Networking Assignment 2

Lab 2: Web Server Lab

In this lab, you will learn the basics of socket programming for TCP connections in Python: how to create a socket, bind it to a specific address and port, and send and receive a HTTP packet. You will also learn some basics of HTTP header format.

You will develop a web server that handles one HTTP request at a time. Your web server should accept and parse the HTTP request, get the requested file from the server’s file system, create an HTTP response message consisting of the requested file preceded by header lines, and send the response directly to the client. If the requested file is not present in the server, the server should send an HTTP “404 Not Found” message back to the client.

Code

Below you will find the skeleton code for the Web server. You are to complete the skeleton code. The places where you need to fill in code are marked with #Fill in start and #Fill in end. Each place may require one or more lines of code.

Running the Server

Put an HTML file (e.g., helloworld.html) in the same directory that the server is in. Run the server program. Determine the IP address of the host that is running the server (e.g., 127.0.0.1). Open a browser and provide the corresponding URL. For example:

http://127.0.0.1:13331/helloworld.html

‘helloworld.html’ is the name of the file you placed in the server directory. Note also the use of the port number after the colon. GradeScope will test your code using port 13331. In the above example, we have used the port number 13331. The browser should then display the contents of helloworld.html. If you omit ":13331", the browser will assume port 80 and you will get the web page from the server only if your server is listening at port 80. Next, try to get a file that is not present at the server. You should get a “404 Not Found” message.

What to Hand in

Submit the code to GradeScope (include helloworld.html if it exists) using your GitHub repository. Program file name must be solution.py.

Notes:

• There are clients (browsers) that will not present HTML content unless encoded HTTP headers are submitted with the message from the web server.
• HTTP status codes “200 OK” and “404 Not Found” are required to be part of the Web Server in order to receive full credit on this assignment.

Skeleton Code

Code is available below and on Google Drive:

https://drive.google.com/file/d/1_9O4p68nlK6a5XC5haOZ5OVTinuF_7cu/view?usp=sharing

Skeleton Python Code for the Web Server

 #import socket module

from socket import *

import sys # In order to terminate the program

def webServer(port=13331):

   serverSocket = socket(AF_INET, SOCK_STREAM)

   #Prepare a server socket

   #Fill in start

   #Fill in end

   while True:

       #Establish the connection

       print('Ready to serve...')

       connectionSocket, addr = #Fill in start      #Fill in end

       try:

           message = #Fill in start    #Fill in end

           filename = message.split()[1]

           f = open(filename[1:])

           outputdata = #Fill in start     #Fill in end

           #Send one HTTP header line into socket

           #Fill in start

           #Fill in end

           #Send the content of the requested file to the client

           for i in range(0, len(outputdata)):

               connectionSocket.send(outputdata[i].encode())

           connectionSocket.send("\r\n".encode())

           connectionSocket.close()

       except IOError:

           #Send response message for file not found (404)

           #Fill in start

           #Fill in end

           #Close client socket

           #Fill in start

           #Fill in end

   serverSocket.close()

   sys.exit()  # Terminate the program after sending the corresponding data

if __name__ == "__main__":

   webServer(13331)