From 73dec34b4b8ba783c5364111ae28ae9a12c6039e Mon Sep 17 00:00:00 2001
From: Luigi Pinca <luigipinca@gmail.com>
Date: Mon, 22 Nov 2021 15:27:29 +0100
Subject: [PATCH] [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.
---
 lib/websocket.js       | 35 +++++++++++++++++++++++++++-----
 test/websocket.test.js | 45 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/lib/websocket.js b/lib/websocket.js
index 40696100e..2613af169 100644
--- a/lib/websocket.js
+++ b/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.
  *
diff --git a/test/websocket.test.js b/test/websocket.test.js
index 6c24feded..84c615b5a 100644
--- a/test/websocket.test.js
+++ b/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', () => {