From ce1f04a062aa3118270dfe77465732db7208c380 Mon Sep 17 00:00:00 2001
From: Gustavo Carneiro <gustavocarneiro@gambitresearch.com>
Date: Fri, 9 Aug 2019 19:01:17 +0100
Subject: [PATCH] Fix an issue with a failed websocket handshake leaving
 connection hanging #3380

---
 CHANGES/3380.bugfix                    |  1 +
 aiohttp/_http_parser.pyx               |  3 +++
 aiohttp/http_parser.py                 |  7 +++++++
 aiohttp/web_protocol.py                |  6 ++++++
 tests/test_web_websocket_functional.py | 28 +++++++++++++++++++++++++-
 5 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 CHANGES/3380.bugfix

diff --git a/CHANGES/3380.bugfix b/CHANGES/3380.bugfix
new file mode 100644
index 00000000000..4c66ff0394b
--- /dev/null
+++ b/CHANGES/3380.bugfix
@@ -0,0 +1 @@
+Fix failed websocket handshake leaving connection hanging.
diff --git a/aiohttp/_http_parser.pyx b/aiohttp/_http_parser.pyx
index b0ee4a18d38..1160c4120f6 100644
--- a/aiohttp/_http_parser.pyx
+++ b/aiohttp/_http_parser.pyx
@@ -533,6 +533,9 @@ cdef class HttpParser:
         else:
             return messages, False, b''
 
+    def set_upgraded(self, val):
+        self._upgraded = val
+
 
 cdef class HttpRequestParser(HttpParser):
 
diff --git a/aiohttp/http_parser.py b/aiohttp/http_parser.py
index b68a6cc24eb..f2881c3bf11 100644
--- a/aiohttp/http_parser.py
+++ b/aiohttp/http_parser.py
@@ -411,6 +411,13 @@ def parse_headers(
 
         return (headers, raw_headers, close_conn, encoding, upgrade, chunked)
 
+    def set_upgraded(self, val: bool) -> None:
+        """Set connection upgraded (to websocket) mode.
+
+        :param bool val: new state.
+        """
+        self._upgraded = val
+
 
 class HttpRequestParser(HttpParser):
     """Read request status line. Exception .http_exceptions.BadStatusLine
diff --git a/aiohttp/web_protocol.py b/aiohttp/web_protocol.py
index 6b8ce04efa5..3aa09d56960 100644
--- a/aiohttp/web_protocol.py
+++ b/aiohttp/web_protocol.py
@@ -549,6 +549,12 @@ async def finish_response(self,
         can get exception information. Returns True if the client disconnects
         prematurely.
         """
+        if self._request_parser is not None:
+            self._request_parser.set_upgraded(False)
+            self._upgrade = False
+            if self._message_tail:
+                self._request_parser.feed_data(self._message_tail)
+                self._message_tail = b''
         try:
             prepare_meth = resp.prepare
         except AttributeError:
diff --git a/tests/test_web_websocket_functional.py b/tests/test_web_websocket_functional.py
index 8c3c30a9157..e8347722acd 100644
--- a/tests/test_web_websocket_functional.py
+++ b/tests/test_web_websocket_functional.py
@@ -5,7 +5,7 @@
 import pytest
 
 import aiohttp
-from aiohttp import web
+from aiohttp import WSServerHandshakeError, web
 from aiohttp.http import WSMsgType
 
 
@@ -827,3 +827,29 @@ async def handler(request):
     ws = await client.ws_connect('/')
     with pytest.raises(TypeError):
         await ws.receive_bytes()
+
+
+async def test_bug3380(loop, aiohttp_client) -> None:
+
+    async def handle_null(request):
+        return aiohttp.web.json_response({'err': None})
+
+    async def ws_handler(request):
+        return web.Response(status=401)
+
+    app = web.Application()
+    app.router.add_route('GET', '/ws', ws_handler)
+    app.router.add_route('GET', '/api/null', handle_null)
+
+    client = await aiohttp_client(app)
+
+    resp = await client.get('/api/null')
+    assert (await resp.json()) == {'err': None}
+    resp.close()
+
+    with pytest.raises(WSServerHandshakeError):
+        await client.ws_connect('/ws')
+
+    resp = await client.get('/api/null', timeout=1)
+    assert (await resp.json()) == {'err': None}
+    resp.close()