submit.py

'''
Coursera:
- Software Defined Networking (SDN) course
-- Programming Assignment 2

Professor: Nick Feamster
Teaching Assistant: Arpit Gupta, Muhammad Shahbaz
'''

### The only things you'll have to edit (unless you're porting this script over to a different language)
### are at the bottom of this file.

import urllib
import urllib2
import hashlib
import random
import email
import email.message
import email.encoders
import StringIO
import sys

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class NullDevice:
  def write(self, s):
    pass

def submit():
  print '==\n== [sandbox] Submitting Solutions \n=='

  (login, password) = loginPrompt()
  if not login:
    print '!! Submission Cancelled'
    return

  print '\n== Connecting to Coursera ... '

  # Part Identifier
  (partIdx, sid) = partPrompt()

  # Get Challenge
  (login, ch, state, ch_aux) = getChallenge(login, sid) #sid is the "part identifier"
  if((not login) or (not ch) or (not state)):
    # Some error occured, error string in first return element.
    print '\n!! Error: %s\n' % login
    return

  # Attempt Submission with Challenge
  ch_resp = challengeResponse(login, password, ch)
  (result, string) = submitSolution(login, ch_resp, sid, output(partIdx), \
                                  source(partIdx), state, ch_aux)

  print '== %s' % string.strip()


# =========================== LOGIN HELPERS - NO NEED TO CONFIGURE THIS =======================================

def loginPrompt():
  """Prompt the user for login credentials. Returns a tuple (login, password)."""
  (login, password) = basicPrompt()
  return login, password


def basicPrompt():
  """Prompt the user for login credentials. Returns a tuple (login, password)."""
  login = raw_input('Login (Email address): ')
  password = raw_input('One-time Password (from the assignment page. This is NOT your own account\'s password): ')
  return login, password

def partPrompt():
  print 'Hello! These are the assignment parts that you can submit:'
  counter = 0
  for part in partFriendlyNames:
    counter += 1
    print str(counter) + ') ' + partFriendlyNames[counter - 1]
  partIdx = int(raw_input('Please enter which part you want to submit (1-' + str(counter) + '): ')) - 1
  return (partIdx, partIds[partIdx])

def getChallenge(email, sid):
  """Gets the challenge salt from the server. Returns (email,ch,state,ch_aux)."""
  url = challenge_url()
  values = {'email_address' : email, 'assignment_part_sid' : sid, 'response_encoding' : 'delim'}
  data = urllib.urlencode(values)
  req = urllib2.Request(url, data)
  response = urllib2.urlopen(req)
  text = response.read().strip()

  # text is of the form email|ch|signature
  splits = text.split('|')
  if(len(splits) != 9):
    print 'Badly formatted challenge response: %s' % text
    return None
  return (splits[2], splits[4], splits[6], splits[8])

def challengeResponse(email, passwd, challenge):
  sha1 = hashlib.sha1()
  sha1.update("".join([challenge, passwd])) # hash the first elements
  digest = sha1.hexdigest()
  strAnswer = ''
  for i in range(0, len(digest)):
    strAnswer = strAnswer + digest[i]
  return strAnswer

def challenge_url():
  """Returns the challenge url."""
  return "https://class.coursera.org/" + URL + "/assignment/challenge"

def submit_url():
  """Returns the submission url."""
  return "https://class.coursera.org/" + URL + "/assignment/submit"

def submitSolution(email_address, ch_resp, sid, output, source, state, ch_aux):
  """Submits a solution to the server. Returns (result, string)."""
  source_64_msg = email.message.Message()
  source_64_msg.set_payload(source)
  email.encoders.encode_base64(source_64_msg)

  output_64_msg = email.message.Message()
  output_64_msg.set_payload(output)
  email.encoders.encode_base64(output_64_msg)
  values = { 'assignment_part_sid' : sid, \
             'email_address' : email_address, \
             'submission' : output_64_msg.get_payload(), \
             'submission_aux' : source_64_msg.get_payload(), \
             'challenge_response' : ch_resp, \
             'state' : state \
           }
  url = submit_url()
  data = urllib.urlencode(values)
  req = urllib2.Request(url, data)
  response = urllib2.urlopen(req)
  string = response.read().strip()

  result = 0
  return result, string

## This collects the source code (just for logging purposes)
def source(partIdx):
  # open the file, get all lines
  f = open(sourceFiles[partIdx])
  src = f.read()
  f.close()
  return src



############ BEGIN ASSIGNMENT SPECIFIC CODE - YOU'LL HAVE TO EDIT THIS ##############

from mininet.net import Mininet
from mininet.util import dumpNodeConnections
from mininet.log import setLogLevel
from mininet.link import TCLink
from CustomTopo import *

# Make sure you change this string to the last segment of your class URL.
# For example, if your URL is https://class.coursera.org/pgm-2012-001-staging, set it to "pgm-2012-001-staging".
URL = 'sdn1-001'

# the "Identifier" you used when creating the part
partIds = ['agPA2']
# used to generate readable run-time information for students
partFriendlyNames = ['Create Custom Topology']
# source files to collect (just for our records)
sourceFiles = ['CustomTopo.py']

def output(partIdx):
  """Uses the student code to compute the output for test cases."""
  outputString = ''

  if partIdx == 0: # This is agPA2
    "Set up link parameters"
    print "a. Setting link parameters"
    "--- core to aggregation switches"
    linkopts1 = {'bw':50, 'delay':'5ms'}
    "--- aggregation to edge switches"
    linkopts2 = {'bw':30, 'delay':'10ms'}
    "--- edge switches to hosts"
    linkopts3 = {'bw':10, 'delay':'15ms'}

    "Creating network and run simple performance test"
    print "b. Creating Custom Topology"
    topo = CustomTopo(linkopts1, linkopts2, linkopts3, fanout=3)

    print "c. Firing up Mininet"
    net = Mininet(topo=topo, link=TCLink)
    net.start()
    h1 = net.get('h1')
    h27 = net.get('h27')

    print "d. Starting Test"
    # Start pings
    outputString = h1.cmd('ping', '-c6', h27.IP())

    print "e. Stopping Mininet"
    net.stop()

  return outputString.strip()

submit()