fix: return 409 error when subdomain is in use instead of silent fallback

Previously, requesting an already-in-use subdomain would silently fall back
to a random subdomain. Now returns a clear 409 Conflict error with a helpful
message telling users to wait or use a different subdomain.

Author: tarasyarema

lib/ClientManager.js

@@ -32,9 +32,11 @@ class ClientManager {
         const clients = this.clients;
         const stats = this.stats;
 
-        // can't ask for id already is use
+        // can't ask for id already in use
         if (clients[id]) {
-            id = hri.random();
+            const err = new Error(`Subdomain '${id}' is already in use. Try again in a few seconds or use a different subdomain.`);
+            err.code = 'SUBDOMAIN_IN_USE';
+            throw err;
         }
 
         const maxSockets = this.opt.max_tcp_sockets;

lib/ClientManager.test.js

@@ -23,14 +23,19 @@ describe('ClientManager', () => {
         manager.removeClient('foobar');
     });
 
-    it('should create a new client with random id if previous exists', async () => {
+    it('should throw SUBDOMAIN_IN_USE error if previous exists', async () => {
         const manager = new ClientManager();
         const clientA = await manager.newClient('foobar');
-        const clientB = await manager.newClient('foobar');
-        assert(clientA.id, 'foobar');
-        assert(manager.hasClient(clientB.id));
-        assert(clientB.id != clientA.id);
-        manager.removeClient(clientB.id);
+        assert.equal(clientA.id, 'foobar');
+
+        try {
+            await manager.newClient('foobar');
+            assert.fail('Should have thrown SUBDOMAIN_IN_USE error');
+        } catch (err) {
+            assert.equal(err.code, 'SUBDOMAIN_IN_USE');
+            assert(err.message.includes('foobar'));
+        }
+
         manager.removeClient('foobar');
     });
 

package.json

@@ -3,7 +3,7 @@
     "name": "@desplega.ai/localtunnel-server",
     "type": "module",
     "description": "expose localhost to the world (desplega.ai fork)",
-    "version": "0.1.2",
+    "version": "0.1.3",
     "license": "MIT",
     "repository": {
         "type": "git",

server.js

@@ -334,7 +334,17 @@ export default function (opt) {
             authOptions.password = ctx.query.password || generatePassword();
         }
 
-        const info = await manager.newClient(reqId, ctx, authOptions);
+        let info;
+        try {
+            info = await manager.newClient(reqId, ctx, authOptions);
+        } catch (err) {
+            if (err.code === 'SUBDOMAIN_IN_USE') {
+                ctx.status = 409;
+                ctx.body = { message: err.message };
+                return;
+            }
+            throw err;
+        }
 
         let url = schema + '://' + info.id + '.' + opt.domain || ctx.request.host;