From a9c6ab03560424ed7dff24849c8ddaa3e1eae62e Mon Sep 17 00:00:00 2001
From: atsuo ishimoto <atsuoishimoto@gmail.com>
Date: Sun, 7 Jul 2019 00:43:59 +0900
Subject: [PATCH] Fixed #30619 -- Made runserver --nothreading use single
 threaded WSGIServer.

Browsers often use multiple connections with Connection: keep-alive.
If --nothreading is specified, the WSGI server cannot accept new
connections until the old connection is closed, causing hangs.

Force Connection: close when --nothreading option is used.
---
 django/core/servers/basehttp.py |  3 +++
 tests/servers/tests.py          | 37 +++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/django/core/servers/basehttp.py b/django/core/servers/basehttp.py
index ef93e28f26..02957c51a2 100644
--- a/django/core/servers/basehttp.py
+++ b/django/core/servers/basehttp.py
@@ -101,6 +101,9 @@ class ServerHandler(simple_server.ServerHandler):
         # connection.
         if 'Content-Length' not in self.headers:
             self.headers['Connection'] = 'close'
+        # Persistent connections require threading server.
+        elif not isinstance(self.request_handler.server, socketserver.ThreadingMixIn):
+            self.headers['Connection'] = 'close'
         # Mark the connection for closing if it's set as such above or if the
         # application sent the header.
         if self.headers.get('Connection') == 'close':
diff --git a/tests/servers/tests.py b/tests/servers/tests.py
index 1f111fb5ae..243b5a4200 100644
--- a/tests/servers/tests.py
+++ b/tests/servers/tests.py
@@ -9,7 +9,9 @@ from urllib.error import HTTPError
 from urllib.parse import urlencode
 from urllib.request import urlopen
 
+from django.core.servers.basehttp import WSGIServer
 from django.test import LiveServerTestCase, override_settings
+from django.test.testcases import LiveServerThread, QuietWSGIRequestHandler
 
 from .models import Person
 
@@ -50,6 +52,15 @@ class LiveServerAddress(LiveServerBase):
         self.assertEqual(self.live_server_url_test[0], self.live_server_url)
 
 
+class LiveServerSingleThread(LiveServerThread):
+    def _create_server(self):
+        return WSGIServer((self.host, self.port), QuietWSGIRequestHandler, allow_reuse_address=False)
+
+
+class SingleThreadLiveServerTestCase(LiveServerTestCase):
+    server_thread_class = LiveServerSingleThread
+
+
 class LiveServerViews(LiveServerBase):
     def test_protocol(self):
         """Launched server serves with HTTP 1.1."""
@@ -162,6 +173,32 @@ class LiveServerViews(LiveServerBase):
             self.assertIn(b"QUERY_STRING: 'q=%D1%82%D0%B5%D1%81%D1%82'", f.read())
 
 
+@override_settings(ROOT_URLCONF='servers.urls')
+class SingleTreadLiveServerViews(SingleThreadLiveServerTestCase):
+    available_apps = ['servers']
+
+    def test_closes_connection_with_content_length(self):
+        """
+        Contrast to
+        LiveServerViews.test_keep_alive_on_connection_with_content_length().
+        Persistent connections require threading server.
+        """
+        conn = HTTPConnection(
+            SingleTreadLiveServerViews.server_thread.host,
+            SingleTreadLiveServerViews.server_thread.port,
+            timeout=1,
+        )
+        try:
+            conn.request('GET', '/example_view/', headers={'Connection': 'keep-alive'})
+            response = conn.getresponse()
+            self.assertTrue(response.will_close)
+            self.assertEqual(response.read(), b'example view')
+            self.assertEqual(response.status, 200)
+            self.assertEqual(response.getheader('Connection'), 'close')
+        finally:
+            conn.close()
+
+
 class LiveServerDatabase(LiveServerBase):
 
     def test_fixtures_loaded(self):