WS test status code support + improved error handing + subprotocol input

server/monitor-types/websocket-upgrade.js

@@ -1,6 +1,26 @@
 const { MonitorType } = require("./monitor-type");
 const WebSocket = require("ws");
 const { UP } = require("../../src/util");
+const { checkStatusCode } = require("../util-server");
+// Define closing error codes https://www.iana.org/assignments/websocket/websocket.xml#close-code-number
+const WS_ERR_CODE = {
+    1002: "Protocol error",
+    1003: "Unsupported Data",
+    1005: "No Status Received",
+    1006: "Abnormal Closure",
+    1007: "Invalid frame payload data",
+    1008: "Policy Violation",
+    1009: "Message Too Big",
+    1010: "Mandatory Extension Missing",
+    1011: "Internal Error",
+    1012: "Service Restart",
+    1013: "Try Again Later",
+    1014: "Bad Gateway",
+    1015: "TLS Handshake Failed",
+    3000: "Unauthorized",
+    3003: "Forbidden",
+    3008: "Timeout",
+};
 
 class WebSocketMonitorType extends MonitorType {
     name = "websocket-upgrade";
@@ -11,24 +31,31 @@ class WebSocketMonitorType extends MonitorType {
     async check(monitor, heartbeat, _server) {
         const [ message, code ] = await this.attemptUpgrade(monitor);
 
-        if (code === 1000) {
+        // If no close code, then an error has occurred, display to user
+        if (typeof code === "undefined") {
+            throw new Error(`${message}`);
+        }
+        // If returned status code matches user controlled accepted status code(default 1000), return success
+        if (checkStatusCode(code, JSON.parse(monitor.accepted_statuscodes_json))) {
             heartbeat.status = UP;
             heartbeat.msg = message;
-        } else {
-            throw new Error(message);
+            return; //success at this point
         }
+
+        // Throw an error using friendly name if defined, fallback to generic msg
+        throw new Error(WS_ERR_CODE[code] || `Unexpected status code: ${code}`);
     }
 
     /**
-     * Uses the builtin Websocket API to establish a connection to target server
+     * Uses the ws Node.js library to establish a connection to target server
      * @param {object} monitor The monitor object for input parameters.
      * @returns {[ string, int ]} Array containing a status message and response code
      */
     async attemptUpgrade(monitor) {
         return new Promise((resolve) => {
             let ws;
-            //If user selected a subprotocol, sets Sec-WebSocket-Protocol header. Subprotocol Identifier column: https://www.iana.org/assignments/websocket/websocket.xml#subprotocol-name
-            ws = monitor.wsSubprotocol === "" ? new WebSocket(monitor.url) : new WebSocket(monitor.url, monitor.wsSubprotocol);
+            // If user inputs subprotocol(s), convert to array, then set Sec-WebSocket-Protocol header. Subprotocol Identifier column: https://www.iana.org/assignments/websocket/websocket.xml#subprotocol-name
+            ws = !monitor.wsSubprotocol ? new WebSocket(monitor.url) : new WebSocket(monitor.url, monitor.wsSubprotocol.replace(/\s/g, "").split(","));
 
             ws.addEventListener("open", (event) => {
                 // Immediately close the connection
@@ -36,7 +63,8 @@ class WebSocketMonitorType extends MonitorType {
             });
 
             ws.onerror = (error) => {
-                // Give user the choice to ignore Sec-WebSocket-Accept header
+                // Give user the choice to ignore Sec-WebSocket-Accept header for non compliant servers
+                // Header in HTTP 101 Switching Protocols response from server, technically already upgraded to WS
                 if (monitor.wsIgnoreSecWebsocketAcceptHeader && error.message === "Invalid Sec-WebSocket-Accept header") {
                     resolve([ "101 - OK", 1000 ]);
                     return;
@@ -46,8 +74,8 @@ class WebSocketMonitorType extends MonitorType {
             };
 
             ws.onclose = (event) => {
-                // Upgrade success, connection closed successfully
-                resolve([ "101 - OK", event.code ]);
+                // Return the close code, if connection didn't close cleanly, return the reason if present
+                resolve([ event.wasClean ? event.code.toString() + " - OK" : event.reason, event.code ]);
             };
         });
     }