another TypeError: a bytes-like object is required, not 'str'

Question

I'm a complete newbie in Python, but I have been programming for fun in (Liberty-)Basic since about 1980.

Using Python 3.5.2 I was testing this script:

import time, telnetlib

host    = "dxc.ve7cc.net"
port    = 23
timeout = 9999

try:
    session = telnetlib.Telnet(host, port, timeout)
except socket.timeout:
    print ("socket timeout")
else:
    session.read_until("login: ")
    session.write("on0xxx\n")
    output = session.read_some()
    while output:
        print (output)
        time.sleep(0.1)  # let the buffer fill up a bit
        output = session.read_some()

Can anyone tell me why I get the TypeError: a bytes-like object is required, not 'str' and how I can solve it?

Possible duplicate of [TypeError: a bytes-like object is required, not 'str'](http://stackoverflow.com/questions/33003498/typeerror-a-bytes-like-object-is-required-not-str) — Marcus Müller, Apr 17 '17 at 21:32

score 2 · Accepted Answer · answered Apr 17 '17 at 21:00

2

In Python 3 (but not in Python 2), str and bytes are distinct types that can't be mixed. You can't write a str directly to a socket; you have to use bytes. Simply prefix the string literal with b to make it a bytes literal.

session.write(b"on0xxx\n")

answered Apr 17 '17 at 21:00

dan04

87,747
23
163
198

this is what I needed, thanks! I also had to add the 'b' here: session.write(b"on0xxx\n") – ON5MF Jurgen Apr 18 '17 at 10:59

score 1 · Answer 2 · answered Apr 17 '17 at 21:01

1

Unlike in Python 2.x, where you don't need to encode the data sent through the net, you have to in Python 3.x. So everything you want to send needs to be encoded with the .encode() function. Everything you receive needs to be decoded with .decode().

answered Apr 17 '17 at 21:01

TacticalBoner

41
4

another TypeError: a bytes-like object is required, not 'str'

2 Answers2