I'm making a python proxy server for a school assignment and I've got the code below. When I run it in my command prompt and attempt to connect to google, the code doesn't make it past connecting the server socket, but the page still connects. I honestly have no idea why it doesn't even go through the connection step. Thoughts?
EDIT: And yeah there's been other homework posts about this but none of them seem to have addressed the fact the sys.exit() on line 8 ends the script (to my knowledge anyway) and whenever we comment it out, the script still does not get past connecting the server socket and hits the "illegal request" exception.
from socket import *
from urllib2 import HTTPError #Used for 404 Not Found error
import sys
import requests
if len(sys.argv) <= 1:
print 'Usage : "python ProxyServer.py server_ip"\n[server_ip : It is the IP Address Of Proxy Server]'
#sys.exit(2)
#POST request extension
print 'Fetching webpage using POST'
r = requests.post('http://httpbin.org/post', data = {'key':'value'})
print 'Printing webpage body'
print r.text
print 'Creating and binding socket for proxy server'
# Create a server socket, bind it to a port and start listening
tcpServerSock = socket(AF_INET, SOCK_STREAM)
# Fill in start.
tcpServerSock.bind(('',8888))
tcpServerSock.listen(10) #the number is the maximum number of connections we want to have
# Fill in end.
while 1:
# Start receiving data from the client
print 'Ready to serve...'
tcpClientSock, addr = tcpServerSock.accept()
print 'Received a connection from:', addr
# Fill in start.
message = tcpClientSock.recv(4096) #receive data with buffer size 4096
# Fill in end.
print 'Printing message'
print message
# Extract the filename from the given message
print message.split()[1]
filename = message.split()[1].partition("/")[2]
print '\n'
print 'Printing file name'
print filename
fileExist = "false"
filetouse = "/" + filename
print '\n'
print 'Printing file to use'
print filetouse
print '\n'
try:
# Check whether the file exist in the cache
f = open(filetouse[1:], "r")
outputdata = f.readlines()
fileExist = "true"
# ProxyServer finds a cache hit and generates a response message
tcpClientSock.send("HTTP/1.0 200 OK\r\n")
tcpClientSock.send("Content-Type:text/html\r\n")
# Fill in start.
for x in range(0,len(outputdata)):
tcpClientSock.send(outputdata[x])
# Fill in end.
print 'Read from cache\n'
# Error handling for file not found in cache
except IOError:
if fileExist == "false":
# Create a socket on the proxyserver
# Fill in start.
print 'Creating server socket\n'
c = socket(AF_INET, SOCK_STREAM)
# Fill in end.
hostn = filename
#hostn = filename.replace("www.","",1)
print 'Printing host to connect'
print hostn
print '\n'
print 'Attempting to connect to hostn\n'
try:
# Connect to the socket to port 80
# Fill in start.
c.connect((hostn,80)) #port 80 is used for http web pages
# Fill in end.
# Create a temporary file on this socket and ask port 80
# for the file requested by the client
fileobj = c.makefile('r', 0)
fileobj.write("GET "+"http://" + filename + "HTTP/1.0\n\n")
# Show what request was made
print "GET "+"http://" + filename + " HTTP/1.0"
# Read the response into buffer
# Fill in start.
buff = fileobj.readlines() #reads until EOF and returns a list with the lines read
# Fill in end.
# Create a new file in the cache for the requested file.
# Also send the response in the buffer to client socket
# and the corresponding file in the cache
tmpFile = open("./" + filename,"wb") #creates the temp file for the requested file
# Fill in start.
for x in range(0, len(buff)):
tmpFile.write(buff[x]) #writes the buffer response into the temp file (cache?)
tcpClientSock.send(buff[x]) #sends the response saved in the buffer to the client
# Fill in end.
tmpFile.close()
except:
print "Illegal request\n"
else:
# HTTP response message for file not found
# Fill in start.
print 'File not found'
# Fill in end.
#404 not found error handling
except HTTPError as e:
print 'The server couldn\'t fulfill the request.'
print 'Error code: ', e.code
# Close the client and the server sockets
tcpClientSock.close()
# Fill in start.
tcpServerSock.close()
# Fill in end
