[fix] Do not throw if the redirect URL is invalid

If the redirect URL is invalid, then emit the error instead of throwing
it, otherwise there is no way to handle it.

Author: lpinca

lib/websocket.js

@@ -618,7 +618,14 @@ function initAsClient(websocket, address, protocols, options) {
   const isUnixSocket = parsedUrl.protocol === 'ws+unix:';
 
   if (!parsedUrl.host && (!isUnixSocket || !parsedUrl.pathname)) {
-    throw new Error(`Invalid URL: ${websocket.url}`);
+    const err = new Error(`Invalid URL: ${websocket.url}`);
+
+    if (websocket._redirects === 0) {
+      throw err;
+    } else {
+      emitErrorAndClose(websocket, err);
+      return;
+    }
   }
 
   const isSecure =
@@ -687,9 +694,7 @@ function initAsClient(websocket, address, protocols, options) {
     if (req === null || req.aborted) return;
 
     req = websocket._req = null;
-    websocket._readyState = WebSocket.CLOSING;
-    websocket.emit('error', err);
-    websocket.emitClose();
+    emitErrorAndClose(websocket, err);
   });
 
   req.on('response', (res) => {
@@ -709,7 +714,14 @@ function initAsClient(websocket, address, protocols, options) {
 
       req.abort();
 
-      const addr = new URL(location, address);
+      let addr;
+
+      try {
+        addr = new URL(location, address);
+      } catch (err) {
+        emitErrorAndClose(websocket, err);
+        return;
+      }
 
       initAsClient(websocket, addr, protocols, options);
     } else if (!websocket.emit('unexpected-response', req, res)) {
@@ -811,6 +823,19 @@ function initAsClient(websocket, address, protocols, options) {
   });
 }
 
+/**
+ * Emit the `'error'` and `'close'` event.
+ *
+ * @param {WebSocket} websocket The WebSocket instance
+ * @param {Error} The error to emit
+ * @private
+ */
+function emitErrorAndClose(websocket, err) {
+  websocket._readyState = WebSocket.CLOSING;
+  websocket.emit('error', err);
+  websocket.emitClose();
+}
+
 /**
  * Create a `net.Socket` and initiate a connection.
  *

test/websocket.test.js

@@ -941,6 +941,51 @@ describe('WebSocket', () => {
         ws.on('close', () => done());
       });
     });
+
+    it('emits an error if the redirect URL is invalid (1/2)', (done) => {
+      const onUpgrade = (req, socket) => {
+        socket.end('HTTP/1.1 302 Found\r\nLocation: ws://\r\n\r\n');
+      };
+
+      server.on('upgrade', onUpgrade);
+
+      const ws = new WebSocket(`ws://localhost:${server.address().port}`, {
+        followRedirects: true
+      });
+
+      ws.on('open', () => done(new Error("Unexpected 'open' event")));
+      ws.on('error', (err) => {
+        assert.ok(err instanceof Error);
+        assert.ok(/Invalid URL/.test(err.message));
+        assert.strictEqual(err.input, 'ws://');
+        assert.strictEqual(ws._redirects, 1);
+
+        server.removeListener('upgrade', onUpgrade);
+        ws.on('close', () => done());
+      });
+    });
+
+    it('emits an error if the redirect URL is invalid (2/2)', (done) => {
+      const onUpgrade = (req, socket) => {
+        socket.end('HTTP/1.1 302 Found\r\nLocation: ws+unix:\r\n\r\n');
+      };
+
+      server.on('upgrade', onUpgrade);
+
+      const ws = new WebSocket(`ws://localhost:${server.address().port}`, {
+        followRedirects: true
+      });
+
+      ws.on('open', () => done(new Error("Unexpected 'open' event")));
+      ws.on('error', (err) => {
+        assert.ok(err instanceof Error);
+        assert.strictEqual(err.message, 'Invalid URL: ws+unix:');
+        assert.strictEqual(ws._redirects, 1);
+
+        server.removeListener('upgrade', onUpgrade);
+        ws.on('close', () => done());
+      });
+    });
   });
 
   describe('Connection with query string', () => {