Cannot Get Strings Across in a Socket Program

Question

I have been looking at some code for a small chat program that I found online. It was originally written for 2.7, but it seems to work with 3.2. The only problem is that I cannot send strings, only numbers:

The chat.py file source code:

from socket import *
HOST = ''
PORT = 8000
s = socket(AF_INET, SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1) 
conn, addr = s.accept() 
print ('Connected by ' + str(addr)) 
i = True
while i is True:
    data = conn.recv(1024)
    print ("Received " + repr(data))
    reply = str(input("Reply: "))
    conn.send(reply)
conn.close()

And the client.py source file:

from socket import * 
HOST = ''
PORT = 8000
s = socket(AF_INET, SOCK_STREAM)
s.connect((HOST, PORT)) # client-side, connects to a host
while True:
    message = str(input("Your Message: "))
    s.send(message)
    print ("Awaiting reply...")
    reply = s.recv(1024) # 1024 is max data that can be received
    print ("Received " + repr(reply))
s.close()

When I run these using two separate terminals, they work, but do not send strings.

Thank you

What error do you get or what happens when you send strings? — Aswin Murugesh
– Aswin Murugesh, Commented Jan 23, 2014 at 19:13

woozyking · Accepted Answer · 2014-01-24 20:46:07Z

2

When you work with sockets, the message you're passing around should probably be in bytes, b'bytes'. In Python 2.x, a str is actually what a bytes is in Python 3.x

So your message should be something like:

message = b'Message I want to pass'

Check here http://docs.python.org/3.3/library/stdtypes.html for more information.

According to http://docs.python.org/3/library/functions.html#input input returns a str, which means you'll have to encode message into bytes as such:

message = message.encode()

Do verify that this is the right approach to convert str to bytes by checking the type of message.

edited Jan 24, 2014 at 20:46

answered Jan 23, 2014 at 19:16

woozyking

5,2601 gold badge25 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user3089646 Over a year ago

Hi @woozyking, thank you for your reply. Would I format my message line like this: message = input(b"Your Message: ")

woozyking Over a year ago

@user3089646 No, it just means that the input you're reading in has to be ensured as bytes type before passing it across sockets. So message = input('Your message: ') is perfectly fine, but after that and before s.send(message), you have to make sure type(message) is bytes.

Stephen Diehl · Accepted Answer · 2014-01-23 19:19:44Z

0

Your socket code is correct, it was just failing due to an unrelated error due to raw_input vs input. You probably intended to read a string from the shell instead of reading a string and trying to evaluate it as Python code which is what input does.

Try this instead:

chat.py

from socket import *
HOST = ''
PORT = 8000
s = socket(AF_INET, SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1) 
conn, addr = s.accept() 
print ('Connected by ' + str(addr)) 
i = True
while i is True:
    data = conn.recv(1024)
    print ("Received " + repr(data))
    reply = str(raw_input("Reply: "))
    conn.send(reply)
conn.close()

client.py

from socket import * 
HOST = ''
PORT = 8000
s = socket(AF_INET, SOCK_STREAM)
s.connect((HOST, PORT)) # client-side, connects to a host
while True:
    message = str(raw_input("Your Message: "))
    s.send(message)
    print ("Awaiting reply...")
    reply = s.recv(1024) # 1024 is max data that can be received
    print ("Received " + repr(reply))
s.close()

answered Jan 23, 2014 at 19:19

Stephen Diehl

8,4795 gold badges42 silver badges57 bronze badges

2 Comments

user3089646 Over a year ago

Hi @Stephen Diehl, thank you for your reply. I was happy to see this work, but realized that my IDLE was 3.2, but my shell was 2.7. When I updated it to 3.2, I get some more errors.

woozyking Over a year ago

In Python 3, raw_input is deprecated. Instead input of Python 3 behaves like raw_input in Python 2

Collectives™ on Stack Overflow

Cannot Get Strings Across in a Socket Program

2 Answers 2

2 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related