Add support for brotli content encoding via brotlipy package (#1532)

10 files changed, 140 insertions, 13 deletions

diff --git a/.travis.yml b/.travis.yml
index edcf5ed5..7fba1a3a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,6 +39,8 @@ matrix:
   include:
     - python: 2.7
       env: TOXENV=py27
+    - python: 2.7
+      env: TOXENV=py27-nobrotli
     - python: 3.4
       env: TOXENV=py34
     - python: 3.5
@@ -49,6 +51,10 @@ matrix:
       env: TOXENV=py37
       dist: xenial
       sudo: required
+    - python: 3.7
+      env: TOXENV=py37-nobrotli
+      dist: xenial
+      sudo: required
     - python: 3.8-dev
       env: TOXENV=py38
       dist: xenial
diff --git a/CHANGES.rst b/CHANGES.rst
index c8d6b9b3..adc55a68 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -18,6 +18,10 @@ dev (master)
 
 * Require and validate certificates by default when using HTTPS (Pull #1507)
 
+* Added support for Brotli content encoding. It is enabled automatically if
+  ``brotlipy`` package is installed which can be requested with
+  ``urllib3[brotli]`` extra. (Pull #1532)
+
 * ... [Short description of non-trivial change.] (Issue #)
 
 
diff --git a/appveyor.yml b/appveyor.yml
index 1f8c7ee3..25dfbcc3 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -13,6 +13,12 @@ environment:
       TOXENV: "py27"
       TOXPY27: "%PYTHON%\\python.exe"
 
+    - PYTHON: "C:\\Python27-x64"
+      PYTHON_VERSION: "2.7.x"
+      PYTHON_ARCH: "64"
+      TOXENV: "py27-nobrotli"
+      TOXPY27: "%PYTHON%\\python.exe"
+
     - PYTHON: "C:\\Python34-x64"
       PYTHON_VERSION: "3.4.x"
       PYTHON_ARCH: "64"
@@ -37,6 +43,12 @@ environment:
       TOXENV: "py37"
       TOXPY37: "%PYTHON%\\python.exe"
 
+    - PYTHON: "C:\\Python37-x64"
+      PYTHON_VERSION: "3.7.x"
+      PYTHON_ARCH: "64"
+      TOXENV: "py37-nobrotli"
+      TOXPY37: "%PYTHON%\\python.exe"
+
 cache:
   - C:\Users\appveyor\AppData\Local\pip\Cache
 
diff --git a/setup.py b/setup.py
index 9b1ec713..750eba81 100755
--- a/setup.py
+++ b/setup.py
@@ -64,6 +64,9 @@ setup(name='urllib3',
       ],
       test_suite='test',
       extras_require={
+          'brotli': [
+              'brotlipy>=0.6.0',
+          ],
           'secure': [
               'pyOpenSSL>=0.14',
               'cryptography>=1.3.4',
diff --git a/src/urllib3/response.py b/src/urllib3/response.py
index 8ecd1a4e..f7c9df5d 100644
--- a/src/urllib3/response.py
+++ b/src/urllib3/response.py
@@ -6,6 +6,11 @@ import logging
 from socket import timeout as SocketTimeout
 from socket import error as SocketError
 
+try:
+    import brotli
+except ImportError:
+    brotli = None
+
 from ._collections import HTTPHeaderDict
 from .exceptions import (
     BodyNotHttplibCompatible, ProtocolError, DecodeError, ReadTimeoutError,
@@ -90,6 +95,18 @@ class GzipDecoder(object):
             self._obj = zlib.decompressobj(16 + zlib.MAX_WBITS)
 
 
+if brotli is not None:
+    class BrotliDecoder(object):
+        def __init__(self):
+            self._obj = brotli.Decompressor()
+
+        def __getattr__(self, name):
+            return getattr(self._obj, name)
+
+        def decompress(self, data):
+            return self._obj.decompress(data)
+
+
 class MultiDecoder(object):
     """
     From RFC7231:
@@ -118,6 +135,9 @@ def _get_decoder(mode):
     if mode == 'gzip':
         return GzipDecoder()
 
+    if brotli is not None and mode == 'br':
+        return BrotliDecoder()
+
     return DeflateDecoder()
 
 
@@ -155,6 +175,8 @@ class HTTPResponse(io.IOBase):
     """
 
     CONTENT_DECODERS = ['gzip', 'deflate']
+    if brotli is not None:
+        CONTENT_DECODERS += ['br']
     REDIRECT_STATUSES = [301, 302, 303, 307, 308]
 
     def __init__(self, body='', headers=None, status=0, version=0, reason=None,
@@ -317,20 +339,26 @@ class HTTPResponse(io.IOBase):
                 if len(encodings):
                     self._decoder = _get_decoder(content_encoding)
 
+    DECODER_ERROR_CLASSES = (IOError, zlib.error)
+    if brotli is not None:
+        DECODER_ERROR_CLASSES += (brotli.Error,)
+
     def _decode(self, data, decode_content, flush_decoder):
         """
         Decode the data passed in and potentially flush the decoder.
         """
+        if not decode_content:
+            return data
+
         try:
-            if decode_content and self._decoder:
+            if self._decoder:
                 data = self._decoder.decompress(data)
-        except (IOError, zlib.error) as e:
+        except self.DECODER_ERROR_CLASSES as e:
             content_encoding = self.headers.get('content-encoding', '').lower()
             raise DecodeError(
                 "Received response with content-encoding: %s, but "
                 "failed to decode it." % content_encoding, e)
-
-        if flush_decoder and decode_content:
+        if flush_decoder:
             data += self._flush_decoder()
 
         return data
diff --git a/src/urllib3/util/request.py b/src/urllib3/util/request.py
index 3ddfcd55..280b8530 100644
--- a/src/urllib3/util/request.py
+++ b/src/urllib3/util/request.py
@@ -5,6 +5,13 @@ from ..packages.six import b, integer_types
 from ..exceptions import UnrewindableBodyError
 
 ACCEPT_ENCODING = 'gzip,deflate'
+try:
+    import brotli as _unused_module_brotli  # noqa: F401
+except ImportError:
+    pass
+else:
+    ACCEPT_ENCODING += ',br'
+
 _FAILEDTELL = object()
 
 
diff --git a/test/__init__.py b/test/__init__.py
index 0719b4b9..b5ead0d4 100644
--- a/test/__init__.py
+++ b/test/__init__.py
@@ -8,6 +8,10 @@ import ssl
 import os
 
 import pytest
+try:
+    import brotli
+except ImportError:
+    brotli = None
 
 from urllib3.exceptions import HTTPWarning
 from urllib3.packages import six
@@ -74,6 +78,16 @@ def onlyPy3(test):
     return wrapper
 
 
+def onlyBrotlipy():
+    return pytest.mark.skipif(
+        brotli is None, reason='only run if brotlipy is present')
+
+
+def notBrotlipy():
+    return pytest.mark.skipif(
+        brotli is not None, reason='only run if brotlipy is absent')
+
+
 def notSecureTransport(test):
     """Skips this test when SecureTransport is in use."""
 
diff --git a/test/test_response.py b/test/test_response.py
index 13c01cda..b6b589a6 100644
--- a/test/test_response.py
+++ b/test/test_response.py
@@ -6,7 +6,7 @@ from io import BytesIO, BufferedReader
 import pytest
 import mock
 
-from urllib3.response import HTTPResponse
+from urllib3.response import HTTPResponse, brotli
 from urllib3.exceptions import (
     DecodeError, ResponseNotChunked, ProtocolError, InvalidHeader
 )
@@ -14,6 +14,8 @@ from urllib3.packages.six.moves import http_client as httplib
 from urllib3.util.retry import Retry, RequestHistory
 from urllib3.util.response import is_fp_closed
 
+from test import onlyBrotlipy
+
 from base64 import b64decode
 
 # A known random (i.e, not-too-compressible) payload generated with:
@@ -208,6 +210,35 @@ class TestResponse(object):
 
         assert r.data == b'foofoofoo'
 
+    @onlyBrotlipy()
+    def test_decode_brotli(self):
+        data = brotli.compress(b'foo')
+
+        fp = BytesIO(data)
+        r = HTTPResponse(fp, headers={'content-encoding': 'br'})
+        assert r.data == b'foo'
+
+    @onlyBrotlipy()
+    def test_chunked_decoding_brotli(self):
+        data = brotli.compress(b'foobarbaz')
+
+        fp = BytesIO(data)
+        r = HTTPResponse(
+            fp, headers={'content-encoding': 'br'}, preload_content=False)
+
+        ret = b''
+        for _ in range(100):
+            ret += r.read(1)
+            if r.closed:
+                break
+        assert ret == b'foobarbaz'
+
+    @onlyBrotlipy()
+    def test_decode_brotli_error(self):
+        fp = BytesIO(b'foo')
+        with pytest.raises(DecodeError):
+            HTTPResponse(fp, headers={'content-encoding': 'br'})
+
     def test_multi_decoding_deflate_deflate(self):
         data = zlib.compress(zlib.compress(b'foo'))
 
diff --git a/test/test_util.py b/test/test_util.py
index 508cb10b..ac527355 100644
--- a/test/test_util.py
+++ b/test/test_util.py
@@ -44,7 +44,7 @@ from urllib3.packages import six
 
 from . import clear_warnings
 
-from test import onlyPy3, onlyPy2
+from test import onlyPy3, onlyPy2, onlyBrotlipy, notBrotlipy
 
 # This number represents a time in seconds, it doesn't mean anything in
 # isolation. Setting to a high-ish value to avoid conflicts with the smaller
@@ -300,14 +300,30 @@ class TestUtil(object):
             parse_url(b"https://www.google.com/")
 
     @pytest.mark.parametrize('kwargs, expected', [
-        ({'accept_encoding': True},
-         {'accept-encoding': 'gzip,deflate'}),
+        pytest.param(
+            {'accept_encoding': True},
+            {'accept-encoding': 'gzip,deflate,br'},
+            marks=onlyBrotlipy(),
+        ),
+        pytest.param(
+            {'accept_encoding': True},
+            {'accept-encoding': 'gzip,deflate'},
+            marks=notBrotlipy(),
+        ),
         ({'accept_encoding': 'foo,bar'},
          {'accept-encoding': 'foo,bar'}),
         ({'accept_encoding': ['foo', 'bar']},
          {'accept-encoding': 'foo,bar'}),
-        ({'accept_encoding': True, 'user_agent': 'banana'},
-         {'accept-encoding': 'gzip,deflate', 'user-agent': 'banana'}),
+        pytest.param(
+            {'accept_encoding': True, 'user_agent': 'banana'},
+            {'accept-encoding': 'gzip,deflate,br', 'user-agent': 'banana'},
+            marks=onlyBrotlipy(),
+        ),
+        pytest.param(
+            {'accept_encoding': True, 'user_agent': 'banana'},
+            {'accept-encoding': 'gzip,deflate', 'user-agent': 'banana'},
+            marks=notBrotlipy(),
+        ),
         ({'user_agent': 'banana'},
          {'user-agent': 'banana'}),
         ({'keep_alive': True},
diff --git a/tox.ini b/tox.ini
index 6e925815..8764a349 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,10 +1,10 @@
 [tox]
-envlist = flake8-py3, py27, py34, py35, py36, py37, py38, pypy
+envlist = flake8-py3, py27, py34, py35, py36, py37, py38, pypy, py{27,37}-nobrotli
 
 [testenv]
 deps= -r{toxinidir}/dev-requirements.txt
-extras= socks,secure
-commands=
+extras = socks,secure,brotli
+commands =
     # Print out the python version and bitness
     pip --version
     python --version
@@ -21,6 +21,12 @@ setenv =
     PYTHONWARNINGS=always::DeprecationWarning
 passenv = CFLAGS LDFLAGS TRAVIS APPVEYOR CRYPTOGRAPHY_OSX_NO_LINK_FLAGS TRAVIS_INFRA
 
+[testenv:py27-nobrotli]
+extras = socks,secure
+
+[testenv:py37-nobrotli]
+extras = socks,secure
+
 [testenv:gae]
 basepython = python2.7
 deps=