Python 3 TypeError: ‘str’ does not support the buffer interface

By mkyong | Updated: September 3, 2015

Viewed: 1,894 (+20 pv/w)

Tags: python error python3

Review a Python 2 socket example

import sys
import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("whois.arin.net", 43))
s.send(sys.argv[1] + "\r\n")

#Python 2.7 send signature
#socket.send(string[, flags])

If compile with Python 3, it prompts the following error?

Traceback (most recent call last):
  File "C:\repos\hc\whois\python\whois.py", line 6, in <module>
    s.send(sys.argv[1] + "\r\n")
TypeError: 'str' does not support the buffer interface

Solution

In Python 3, the socket accepts bytes, you need to convert string to bytes with a encode() function like this :

import sys
import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("whois.arin.net", 43))

#convert string to bytes
s.send((sys.argv[1] + "\r\n").encode())

#Python 3.4 send signature
#socket.send(bytes[, flags])

P.S Tested with Python 3.4.3

References

1. Python 3 socket send documentation
2. Python 2 socket send documentation
3. Python Whois client example