Unit Testing websocket connections in matlab_view

Author: Tanmay Das

.github/actions/generate-code-coverage/action.yml

@@ -10,10 +10,10 @@ runs:
       with:
         python-version: '3.8'
 
-    - name: Use Node.js 13.x
+    - name: Use Node.js 18.x
       uses: actions/setup-node@v3
       with:
-        node-version: 13.x
+        node-version: 18
 
     - name: Install Python build dependencies
       run: |

matlab_proxy/app.py

@@ -304,8 +304,8 @@ async def termination_integration_delete(req):
     # End termination with 0 exit code to indicate intentional termination
     await req.app.shutdown()
     await req.app.cleanup()
-    """When testing with pytest, its not possible to catch sys.exit(0) using the construct 
-    'with pytest.raises()', there by causing the test : test_termination_integration_delete() 
+    """When testing with pytest, its not possible to catch sys.exit(0) using the construct
+    'with pytest.raises()', there by causing the test : test_termination_integration_delete()
     to fail. Inorder to avoid this, adding the below if condition to check to skip sys.exit(0) when testing
     """
     logger.debug("Exiting with return code 0")
@@ -408,6 +408,10 @@ async def matlab_view(req):
     Returns:
         WebSocketResponse or HTTPResponse: based on the Request type.
     """
+    # Special keys for web socket requests
+    CONNECTION = "connection"
+    UPGRADE = "upgrade"
+
     reqH = req.headers.copy()
 
     state = req.app["state"]
@@ -417,11 +421,12 @@ async def matlab_view(req):
     matlab_base_url = f"{matlab_protocol}://127.0.0.1:{matlab_port}"
 
     # WebSocket
+    # According to according to RFC6455 (https://www.rfc-editor.org/rfc/rfc6455.html)
+    # the values of 'connection' and 'upgrade'  keys of request header
+    # should be ASCII case-insensitive matches.
     if (
-        reqH.get("connection")
-        and reqH.get("connection").lower() == "upgrade"
-        and reqH.get("upgrade")
-        and reqH.get("upgrade").lower() == "websocket"
+        reqH.get(CONNECTION, "").lower() == UPGRADE
+        and reqH.get(UPGRADE, "").lower() == "websocket"
         and req.method == "GET"
     ):
         ws_server = web.WebSocketResponse()

tests/test_app.py

@@ -445,18 +445,37 @@ async def test_matlab_proxy_http_post_request(proxy_payload, test_server):
             raise ConnectionError
 
 
-async def test_matlab_proxy_web_socket(test_server):
+# While acceessing matlab-proxy directly, the web socket request looks like
+#     {
+#         "connection": "Upgrade",
+#         "Upgrade": "websocket",
+#     }
+# whereas while accessing matlab-proxy with nginx as the reverse proxy, the nginx server
+# modifies the web socket request to
+#     {
+#         "connection": "upgrade",
+#         "upgrade": "websocket",
+#     }
+@pytest.mark.parametrize(
+    "headers",
+    [
+        {
+            "connection": "Upgrade",
+            "Upgrade": "websocket",
+        },
+        {
+            "connection": "upgrade",
+            "upgrade": "websocket",
+        },
+    ],
+)
+async def test_matlab_proxy_web_socket(test_server, headers):
     """Test to check if test_server proxies web socket request to fake matlab server
 
     Args:
         test_server (aiohttp_client): Test Server to send HTTP Requests.
     """
 
-    headers = {
-        "connection": "Upgrade",
-        "upgrade": "websocket",
-    }
-
     resp = await test_server.ws_connect("/http_ws_request.html", headers=headers)
     text = await resp.receive()
     assert text.type == aiohttp.WSMsgType.CLOSED