Python "builtins.TypeError: must be str, not bytes" - Twisted LineReceiver.sendLine()

Question

I am following the Twisted tutorial (see bottom of here)

I am trying to connect to the chat server but i keep getting the following error

File "/Users/kevin/anaconda3/lib/python3.6/site-packages/twisted/internet/tcp.py", line 1073, in doRead
    protocol.makeConnection(transport)
  File "/Users/kevin/anaconda3/lib/python3.6/site-packages/twisted/internet/protocol.py", line 510, in makeConnection
    self.connectionMade()
  File "twisted_chat.py", line 12, in connectionMade
    self.sendLine("What's your name?") <------------- This line
  File "/Users/kevin/anaconda3/lib/python3.6/site-packages/twisted/protocols/basic.py", line 635, in sendLine
    return self.transport.write(line + self.delimiter)
builtins.TypeError: must be str, not bytes

The code that seems to be triggering this error is

from twisted.internet.protocol import Factory
from twisted.protocols.basic import LineReceiver
from twisted.internet import reactor

class Chat(LineReceiver):
    def __init__(self, users):
        self.users = users
        self.name = None
        self.state = "GETNAME"

    def connectionMade(self):
        self.sendLine("What's your name?") <------- This line

    def connectionLost(self, reason):
        if self.name in self.users:
            del self.users[self.name]

I am a bit puzzled since "What's your name?" is clearly a string, not bytes. I am using Python 3.6 with Twisted 17.9.0

EDIT: I tried running the same code in python 3.4 and i got builtins.TypeError: Can't convert 'bytes' object to str implicitly

I've been searching but can't seem to find an solution to the problem. Does anyone know how I can fix this?

Answer 1

Your code should run fine in Python/Anaconda v2 but not in v3 unless you've left some code out. For Py v3+, use either:

self.sendLine( b"What's your name?" )

self.sendLine( "What's your name?".encode('utf8') )

As you can see in docs for LineReceiver.sendLine the argument must be type bytes.