Remove unnecessary use of six.binary_type and six.b (urllib3#1440)

The 'bytes' type is available on all supported Pythons. On Python 2 it
is an alias of str (same as six). Likewise, the bytes literal is also
available. Reduce unnecessary compatibility shims and use modern Python
idioms. Makes the code more forward compatible with Python 3.

src/urllib3/connection.py

@@ -202,13 +202,13 @@ def request_chunked(self, method, url, body=None, headers=None):
         self.endheaders()
 
         if body is not None:
-            stringish_types = six.string_types + (six.binary_type,)
+            stringish_types = six.string_types + (bytes,)
             if isinstance(body, stringish_types):
                 body = (body,)
             for chunk in body:
                 if not chunk:
                     continue
-                if not isinstance(chunk, six.binary_type):
+                if not isinstance(chunk, bytes):
                     chunk = chunk.encode('utf8')
                 len_str = hex(len(chunk))[2:]
                 self.send(len_str.encode('utf-8'))

src/urllib3/response.py

@@ -11,7 +11,7 @@
     BodyNotHttplibCompatible, ProtocolError, DecodeError, ReadTimeoutError,
     ResponseNotChunked, IncompleteRead, InvalidHeader
 )
-from .packages.six import string_types as basestring, binary_type, PY3
+from .packages.six import string_types as basestring, PY3
 from .packages.six.moves import http_client as httplib
 from .connection import HTTPException, BaseSSLError
 from .util.response import is_fp_closed, is_response_to_head
@@ -23,7 +23,7 @@ class DeflateDecoder(object):
 
     def __init__(self):
         self._first_try = True
-        self._data = binary_type()
+        self._data = b''
         self._obj = zlib.decompressobj()
 
     def __getattr__(self, name):
@@ -69,7 +69,7 @@ def __getattr__(self, name):
         return getattr(self._obj, name)
 
     def decompress(self, data):
-        ret = binary_type()
+        ret = b''
         if self._state == GzipDecoderState.SWALLOW_DATA or not data:
             return ret
         while True:
@@ -159,7 +159,7 @@ def __init__(self, body='', headers=None, status=0, version=0, reason=None,
         self.msg = msg
         self._request_url = request_url
 
-        if body and isinstance(body, (basestring, binary_type)):
+        if body and isinstance(body, (basestring, bytes)):
             self._body = body
 
         self._pool = pool

src/urllib3/util/ssl_.py

@@ -66,7 +66,7 @@ def _const_compare_digest_backport(a, b):
         import ipaddress
 
         def inet_pton(_, host):
-            if isinstance(host, six.binary_type):
+            if isinstance(host, bytes):
                 host = host.decode('ascii')
             return ipaddress.ip_address(host)
 
@@ -363,7 +363,7 @@ def is_ipaddress(hostname):
     :param str hostname: Hostname to examine.
     :return: True if the hostname is an IP address, False otherwise.
     """
-    if six.PY3 and isinstance(hostname, six.binary_type):
+    if six.PY3 and isinstance(hostname, bytes):
         # IDN A-label bytes are ASCII compatible.
         hostname = hostname.decode('ascii')
 

test/test_ssl.py

@@ -1,6 +1,5 @@
 import mock
 import pytest
-from six import b
 from urllib3.util import ssl_
 from urllib3.exceptions import SNIMissingWarning
 
@@ -10,15 +9,15 @@
     '::',
     '127.0.0.1',
     '8.8.8.8',
-    b('127.0.0.1')
+    b'127.0.0.1'
 ])
 def test_is_ipaddress_true(addr):
     assert ssl_.is_ipaddress(addr)
 
 
 @pytest.mark.parametrize('addr', [
     'www.python.org',
-    b('www.python.org')
+    b'www.python.org'
 ])
 def test_is_ipaddress_false(addr):
     assert not ssl_.is_ipaddress(addr)

test/with_dummyserver/test_chunked_transfer.py

@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 
 from urllib3 import HTTPConnectionPool
-from urllib3.packages import six
 from dummyserver.testcase import SocketDummyServerTestCase
 
 
@@ -50,7 +49,7 @@ def _test_body(self, data):
 
         self.assertIn(b'Transfer-Encoding: chunked', header.split(b'\r\n'))
         if data:
-            bdata = data if isinstance(data, six.binary_type) else data.encode('utf-8')
+            bdata = data if isinstance(data, bytes) else data.encode('utf-8')
             self.assertIn(b'\r\n' + bdata + b'\r\n', body)
             self.assertTrue(body.endswith(b'\r\n0\r\n\r\n'))