Learning Python Networking - Second Edition

Downloading an RFC with the socket module

Now, we are going to create the same script but, instead of using urllib or requests, we are going to use the socket module for working at a low level. For this, create a text file called RFC_download_socket.py:

#!/usr/bin/env python3import sys, sockettry:    rfc_number = int(sys.argv[1])except (IndexError, ValueError):    print('Must supply an RFC number as first argument')    sys.exit(2)host = 'www.rfc-editor.org'port = 80sock = socket.create_connection((host, port))req = ('GET /rfc/rfc{rfcnum}.txt HTTP/1.1\r\n''Host: {host}:{port}\r\n''User-Agent: Python {version}\r\n''Connection: close\r\n''\r\n')req = req.format(rfcnum=rfc_number,host=host,port=port,version=sys.version_info[0])sock.sendall(req.encode('ascii')) ...