Fix #758: Handle empty body with gzipped encoding

aiohttp/protocol.py

@@ -286,7 +286,8 @@ def __call__(self, out, buf):
             length = 8
 
         # payload decompression wrapper
-        if self.compression and self.message.compression:
+        if (self.response_with_body and
+                self.compression and self.message.compression):
             out = DeflateBuffer(out, self.message.compression)
 
         # payload parser

aiohttp/web_reqrep.py

@@ -482,6 +482,10 @@ def enable_compression(self, force=None):
         # Backwards compatibility for when force was a bool <0.17.
         if type(force) == bool:
             force = ContentCoding.deflate if force else ContentCoding.identity
+        elif force is not None:
+            assert isinstance(force, ContentCoding), ("force should one of "
+                                                      "None, bool or "
+                                                      "ContentEncoding")
 
         self._compression = True
         self._compression_force = force

tests/conftest.py

@@ -222,6 +222,12 @@ def post(self, path, **kwargs):
         url = self._url + path
         return self._session.post(url, **kwargs)
 
+    def delete(self, path, **kwargs):
+        while path.startswith('/'):
+            path = path[1:]
+        url = self._url + path
+        return self._session.delete(url)
+
     def ws_connect(self, path, **kwargs):
         while path.startswith('/'):
             path = path[1:]

tests/test_client_functional.py

@@ -432,3 +432,22 @@ def handler(request):
         resp = yield from client.get('/', version=aiohttp.HttpVersion11)
         assert resp.status == 200
         resp.close()
+
+
+@pytest.mark.run_loop
+def test_204_with_gzipped_content_encoding(create_app_and_client):
+    @asyncio.coroutine
+    def handler(request):
+        resp = web.StreamResponse(status=204)
+        resp.content_length = 0
+        resp.content_type = 'application/json'
+        # resp.enable_compression(web.ContentCoding.gzip)
+        resp.headers['Content-Encoding'] = 'gzip'
+        yield from resp.prepare(request)
+        return resp
+
+    app, client = yield from create_app_and_client()
+    app.router.add_route('DELETE', '/', handler)
+    resp = yield from client.delete('/')
+    assert resp.status == 204
+    yield from resp.release()