Fix deflate compression (#4506)

CHANGES/4506.bugfix

@@ -0,0 +1 @@
+Fixed 'deflate' compressions. According to RFC 2616 now.

aiohttp/http_parser.py

@@ -727,7 +727,7 @@ def flush(self) -> bytes:
             self.decompressor = BrotliDecoder()  # type: Any
         else:
             zlib_mode = (16 + zlib.MAX_WBITS
-                         if encoding == 'gzip' else -zlib.MAX_WBITS)
+                         if encoding == 'gzip' else zlib.MAX_WBITS)
             self.decompressor = zlib.decompressobj(wbits=zlib_mode)
 
     def set_exception(self, exc: BaseException) -> None:

aiohttp/http_websocket.py

@@ -273,7 +273,7 @@ def feed_data(self, data: bytes) -> Tuple[bool, bytes]:
     def _feed_data(self, data: bytes) -> Tuple[bool, bytes]:
         for fin, opcode, payload, compressed in self.parse_frame(data):
             if compressed and not self._decompressobj:
-                self._decompressobj = zlib.decompressobj(wbits=-zlib.MAX_WBITS)
+                self._decompressobj = zlib.decompressobj(wbits=zlib.MAX_WBITS)
             if opcode == WSMsgType.CLOSE:
                 if len(payload) >= 2:
                     close_code = UNPACK_CLOSE_CODE(payload[:2])[0]
@@ -567,11 +567,13 @@ async def _send_frame(self, message: bytes, opcode: int,
         # if self.compress and opcode < 8 and len(message) > 124:
         if (compress or self.compress) and opcode < 8:
             if compress:
+                assert compress > 0
                 # Do not set self._compress if compressing is for this frame
-                compressobj = zlib.compressobj(wbits=-compress)
+                compressobj = zlib.compressobj(wbits=compress)
             else:  # self.compress
                 if not self._compressobj:
-                    self._compressobj = zlib.compressobj(wbits=-self.compress)
+                    assert self.compress > 0
+                    self._compressobj = zlib.compressobj(wbits=self.compress)
                 compressobj = self._compressobj
 
             message = compressobj.compress(message)

aiohttp/http_writer.py

@@ -55,7 +55,7 @@ def enable_chunking(self) -> None:
 
     def enable_compression(self, encoding: str='deflate') -> None:
         zlib_mode = (16 + zlib.MAX_WBITS
-                     if encoding == 'gzip' else -zlib.MAX_WBITS)
+                     if encoding == 'gzip' else zlib.MAX_WBITS)
         self._compress = zlib.compressobj(wbits=zlib_mode)
 
     def _write(self, chunk: bytes) -> None:

aiohttp/multipart.py

@@ -479,7 +479,7 @@ def _decode_content(self, data: bytes) -> bytes:
         encoding = self.headers.get(CONTENT_ENCODING, '').lower()
 
         if encoding == 'deflate':
-            return zlib.decompress(data, -zlib.MAX_WBITS)
+            return zlib.decompress(data, zlib.MAX_WBITS)
         elif encoding == 'gzip':
             return zlib.decompress(data, 16 + zlib.MAX_WBITS)
         elif encoding == 'identity':
@@ -978,7 +978,7 @@ def enable_encoding(self, encoding: str) -> None:
 
     def enable_compression(self, encoding: str='deflate') -> None:
         zlib_mode = (16 + zlib.MAX_WBITS
-                     if encoding == 'gzip' else -zlib.MAX_WBITS)
+                     if encoding == 'gzip' else zlib.MAX_WBITS)
         self._compress = zlib.compressobj(wbits=zlib_mode)
 
     async def write_eof(self) -> None:

aiohttp/web_response.py

@@ -669,6 +669,7 @@ async def _start(self, request: 'BaseRequest') -> AbstractStreamWriter:
         return await super()._start(request)
 
     def _compress_body(self, zlib_mode: int) -> None:
+        assert zlib_mode > 0
         compressobj = zlib.compressobj(wbits=zlib_mode)
         body_in = self._body
         assert body_in is not None
@@ -683,7 +684,7 @@ async def _do_start_compression(self, coding: ContentCoding) -> None:
             # Instead of using _payload_writer.enable_compression,
             # compress the whole body
             zlib_mode = (16 + zlib.MAX_WBITS
-                         if coding == ContentCoding.gzip else -zlib.MAX_WBITS)
+                         if coding == ContentCoding.gzip else zlib.MAX_WBITS)
             body_in = self._body
             assert body_in is not None
             if self._zlib_executor_size is not None and \

tests/test_http_parser.py

@@ -837,7 +837,7 @@ async def test_http_payload_parser_length(self, stream) -> None:
         assert b'12' == b''.join(d for d, _ in out._buffer)
         assert b'45' == tail
 
-    _comp = zlib.compressobj(wbits=-zlib.MAX_WBITS)
+    _comp = zlib.compressobj(wbits=zlib.MAX_WBITS)
     _COMPRESSED = b''.join([_comp.compress(b'data'), _comp.flush()])
 
     async def test_http_payload_parser_deflate(self, stream) -> None:

tests/test_http_writer.py

@@ -117,7 +117,7 @@ async def test_write_payload_chunked_filter_mutiple_chunks(
         b'2\r\na2\r\n0\r\n\r\n')
 
 
-compressor = zlib.compressobj(wbits=-zlib.MAX_WBITS)
+compressor = zlib.compressobj(wbits=zlib.MAX_WBITS)
 COMPRESSED = b''.join([compressor.compress(b'data'), compressor.flush()])
 
 

tests/test_web_functional.py

@@ -953,7 +953,7 @@ async def test_response_with_precompressed_body_deflate(
 
     async def handler(request):
         headers = {'Content-Encoding': 'deflate'}
-        zcomp = zlib.compressobj(wbits=-zlib.MAX_WBITS)
+        zcomp = zlib.compressobj(wbits=zlib.MAX_WBITS)
         data = zcomp.compress(b'mydata') + zcomp.flush()
         return web.Response(body=data, headers=headers)
 

tests/test_web_sendfile_functional.py

@@ -742,7 +742,7 @@ async def handler(request):
 
     resp = await client.get('/')
     assert resp.status == 200
-    zcomp = zlib.compressobj(wbits=-zlib.MAX_WBITS)
+    zcomp = zlib.compressobj(wbits=zlib.MAX_WBITS)
     expected_body = zcomp.compress(b'file content\n') + zcomp.flush()
     assert expected_body == await resp.read()
     assert 'application/octet-stream' == resp.headers['Content-Type']

tests/test_websocket_parser.py

@@ -24,7 +24,7 @@ def build_frame(message, opcode, use_mask=False, noheader=False, is_fin=True,
                 compress=False):
     # Send a frame over the websocket with message as its payload.
     if compress:
-        compressobj = zlib.compressobj(wbits=-9)
+        compressobj = zlib.compressobj(wbits=9)
         message = compressobj.compress(message)
         message = message + compressobj.flush(zlib.Z_SYNC_FLUSH)
         if message.endswith(_WS_DEFLATE_TRAILING):