Fix byte string issue in Python 2

Twisted seems to return a byte string for the client and server IP
address. It is easily rectified by casting to the required unicode
string. Also added a test to ensure this is also handled correctly in
the X-Forwarded-For header parsing.

daphne/http_protocol.py

@@ -63,8 +63,10 @@ class WebRequest(http.Request):
                 upgrade_header = self.requestHeaders.getRawHeaders(b"Upgrade")[0]
             # Get client address if possible
             if hasattr(self.client, "host") and hasattr(self.client, "port"):
-                self.client_addr = [self.client.host, self.client.port]
-                self.server_addr = [self.host.host, self.host.port]
+                # client.host and host.host are byte strings in Python 2, but spec
+                # requires unicode string.
+                self.client_addr = [six.text_type(self.client.host), self.client.port]
+                self.server_addr = [six.text_type(self.host.host), self.host.port]
             else:
                 self.client_addr = None
                 self.server_addr = None

daphne/tests/test_utils.py

@@ -1,6 +1,7 @@
 # coding: utf8
 from __future__ import unicode_literals
 from unittest import TestCase
+import six
 
 from twisted.web.http_headers import Headers
 
@@ -17,10 +18,9 @@ class TestXForwardedForParsing(TestCase):
             b'X-Forwarded-For': [b'10.1.2.3'],
             b'X-Forwarded-Port': [b'1234']
         })
-        self.assertEqual(
-            parse_x_forwarded_for(headers),
-            ['10.1.2.3', 1234]
-        )
+        result = parse_x_forwarded_for(headers)
+        self.assertEqual(result, ['10.1.2.3', 1234])
+        self.assertIsInstance(result[0], six.text_type)
 
     def test_address_only(self):
         headers = Headers({