Fix issue with local mode bodyless responses causing clients to hang

fixes aws#525

CHANGELOG.rst

@@ -2,6 +2,13 @@
 CHANGELOG
 =========
 
+Next Release (TBD)
+==================
+* Fix issue with chalice local mode causing http clients to hang on responses
+  with no body
+  (`#525 <https://github.com/aws/chalice/issues/525>`__)
+
+
 1.0.2
 =====
 

chalice/local.py

@@ -201,7 +201,7 @@ class NotAuthorizedError(LocalGatewayException):
 
 
 class NoOptionsRouteDefined(LocalGatewayException):
-    CODE = 403
+    CODE = 200
 
 
 class LambdaContext(object):
@@ -574,6 +574,7 @@ def _send_http_response_with_body(self, code, headers, body):
 
     def _send_http_response_no_body(self, code, headers):
         # type: (int, HeaderType) -> None
+        headers['Content-Length'] = '0'
         self.send_response(code)
         for k, v in headers.items():
             self.send_header(k, v)

tests/integration/test_local.py

@@ -0,0 +1,93 @@
+import socket
+import contextlib
+from threading import Thread
+import pytest
+import requests
+from chalice import app
+from chalice.local import LocalDevServer
+from chalice.config import Config
+
+
+class ThreadedLocalServer(Thread):
+    def __init__(self, port):
+        super(ThreadedLocalServer, self).__init__()
+        self._app_object = None
+        self._config = None
+        self._port = port
+        self._server = None
+
+    def configure(self, app_object, config):
+        self._app_object = app_object
+        self._config = config
+
+    def run(self):
+        self._server = LocalDevServer(
+            self._app_object, self._config, self._port)
+        self._server.serve_forever()
+
+    def shutdown(self):
+        if self._server is not None:
+            self._server.server.shutdown()
+
+
+@pytest.fixture
+def config():
+    return Config()
+
+
+@pytest.fixture()
+def unused_tcp_port():
+    with contextlib.closing(socket.socket()) as sock:
+        sock.bind(('127.0.0.1', 0))
+        return sock.getsockname()[1]
+
+
+@pytest.fixture()
+def local_server_factory(unused_tcp_port):
+    threaded_server = ThreadedLocalServer(unused_tcp_port)
+
+    def create_server(app_object, config):
+        threaded_server.configure(app_object, config)
+        threaded_server.start()
+        return threaded_server, unused_tcp_port
+
+    try:
+        yield create_server
+    finally:
+        threaded_server.shutdown()
+
+
+@pytest.fixture
+def sample_app():
+    demo = app.Chalice('demo-app')
+
+    @demo.route('/', methods=['GET'])
+    def index():
+        return {'hello': 'world'}
+
+    @demo.route('/test-cors', methods=['POST'], cors=True)
+    def test_cors():
+        return {'hello': 'world'}
+
+    return demo
+
+
+def _call_local_server(method, path, port, timeout=0.5):
+    return method('http://localhost:{port}{path}'.format(
+        path=path, port=port), timeout=timeout)
+
+
+def test_can_accept_get_request(config, sample_app, local_server_factory):
+    local_server, port = local_server_factory(sample_app, config)
+    response = _call_local_server(requests.get, '/', port)
+    assert response.status_code == 200
+    assert response.text == '{"hello": "world"}'
+
+
+def test_can_accept_options_request(config, sample_app, local_server_factory):
+    local_server, port = local_server_factory(sample_app, config)
+    response = _call_local_server(requests.options, '/test-cors', port)
+    assert response.status_code == 200
+    assert response.headers['Content-Length'] == '0'
+    assert response.headers['Access-Control-Allow-Methods'] == 'POST,OPTIONS'
+    assert response.text == ''

tests/unit/test_local.py

@@ -345,6 +345,7 @@ def test_will_respond_with_custom_cors_enabled(handler):
                         headers=headers)
     handler.do_GET()
     response = handler.wfile.getvalue().splitlines()
+    assert b'HTTP/1.1 200 OK' in response
     assert b'Access-Control-Allow-Origin: https://foo.bar' in response
     assert (b'Access-Control-Allow-Headers: Authorization,Content-Type,'
             b'Header-A,Header-B,X-Amz-Date,X-Amz-Security-Token,'
@@ -360,13 +361,15 @@ def test_will_respond_with_custom_cors_enabled_options(handler):
                         headers=headers)
     handler.do_OPTIONS()
     response = handler.wfile.getvalue().decode().splitlines()
+    assert 'HTTP/1.1 200 OK' in response
     assert 'Access-Control-Allow-Origin: https://foo.bar' in response
     assert ('Access-Control-Allow-Headers: Authorization,Content-Type,'
             'Header-A,Header-B,X-Amz-Date,X-Amz-Security-Token,'
             'X-Api-Key') in response
     assert 'Access-Control-Expose-Headers: Header-A,Header-B' in response
     assert 'Access-Control-Max-Age: 600' in response
     assert 'Access-Control-Allow-Credentials: true' in response
+    assert 'Content-Length: 0' in response
 
     # Ensure that the Access-Control-Allow-Methods header is sent
     # and that it sends all the correct methods over.