Python 3.4 Socket and Threading issues - python-3.x

Question

import sys
import socket
import threading
import time
QUIT = False
class ClientThread(threading.Thread): # Class that implements the client threads in this server
def __init__(self, client_sock): # Initialize the object, save the socket that this thread will use.
threading.Thread.__init__(self)
self.client = client_sock
def run(self): # Thread's main loop. Once this function returns, the thread is finished and dies.
global QUIT # Need to declare QUIT as global, since the method can change it/
done = False
cmd = self.readline() #Read data from the socket and process it
while not done:
if 'quit' == cmd:
self.writeline('Ok, bye')
QUIT = True
done = True
elif 'bye' == cmd:
self.writeline('Ok, bye')
done = True
else:
self.writeline(self.name)
cmd = self.readline()
self.client.close() # Make sure socket is closed when we're done with it
return
def readline(self): # Helper function, read up to 1024 chars from the socket, and returns them as a string
result = self.client.recv(1024)
if None != result: # All letters in lower case and without and end of line markers
result = result.strip().lower()
return result
def writeline(self, text): # Helper function, writes the given string to the socket with and end of line marker at end
self.client.send(text.strip() + '\n')
class Server: # Server class. Opens up a socket and listens for incoming connections.
def __init__(self): # Every time a new connection arrives, new thread object is created and
self.sock = None # defers the processing of the connection to it
self.thread_list = []
def run(self): # Server main loop: Creates the server (incoming) socket, listens > creates thread to handle it
all_good = False
try_count = 0 # Attempt to open the socket
while not all_good:
if 3 < try_count: # Tried more than 3 times without success, maybe post is in use by another program
sys.exit(1)
try:
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # Create the socket
port = 80
self.sock.bind(('127.0.0.1', port)) # Bind to the interface and port we want to listen on
self.sock.listen(5)
all_good = True
break
except socket.error, err:
print('Socket connection error... Waiting 10 seconds to retry.')
del self.sock
time.sleep(10)
try_count += 1
print( 'Server is listening for incoming connections.')
print('Try to connect through the command line with:')
print('telnet localhost 80')
print('and then type whatever you want.')
print()
print("typing 'bye' finishes the thread. but not the server",)
print("eg. you can quit telnet, run it again and get a different ",)
print("thread name")
print("typing 'quit' finishes the server")
try:
while not QUIT:
try:
self.sock.settimeout(0.500)
client = self.sock.accept()[0]
except socket.timeout:
time.sleep(1)
if QUIT:
print('Received quit command. Shutting down...')
break
continue
new_thread = ClientThread(client)
print('Incoming Connection. Started thread ',)
print(new_thread.getName())
self.thread_list.append(new_thread)
new_thread.start()
for thread in self.thread_list:
if not thread.isAlive():
self.thread_list.remove(thread)
thread.join()
except KeyboardInterrupt:
print('Ctrl+C pressed... Shutting Down')
except Exception as err:
print('Exception caught: %s\nClosing...' % err)
for thread in self.thread_list:
thread.join(1.0)
self.sock.close()
if "__main__" == __name__:
server = Server()
server.run()
print('Terminated')
Resolved many issues, these are the ones left, thank you guys!
1st error: socket.error, err.This specifically tells me that this no longer works in Python 3.4, but does not offer an alternative.
2nd Error: except socket.error, err: Python 3.4 does not support this syntax
3rd Error: self.readline(), I also have to assume writeline does not work also.
In this case, self.readline() is totally not working, I get an error that says AttributeError: 'ClientThread' object has no attribute 'readline'
This only happens after the thread is created. Console shows:
Incoming connection. Started thread.
Thread-1
Then flags that error.
4th Error: Cannot get 2to3 to run? Terminal says not recognised as internal command, and python console gives a big FU.
Can I get any rectification suggestions for the following errors please?

Answer 1

There are multiple issues that prevent your code from woring on python3
you're using python2 print statements, so your code can't possibly run on python3 where print() is a function.
the recv and send methods require/return bytes in python3, not str
the syntax for catching errors is except ExceptionClass as name

Answer 2

The first step in porting Python 2 code to Python 3 is to run it though the 2to3 program that comes with Python.
If you run your code through 2to3 with the -w option, it will fix a lot of your problems automagically.
> 2to3 -w --no-diffs socktest1.py
If you want to see what would be changed, but not change anything;
> 2to3 socktest1.py |less