chore: Raise more user-friendly error if WAD server connection fails (#317)

Author: mykola-mokhnach

lib/winappdriver.js

@@ -7,7 +7,7 @@ import { getWADExecutablePath } from './installer';
 import { waitForCondition } from 'asyncbox';
 import { execSync } from 'child_process';
 import { util } from 'appium/support';
-import { findAPortNotInUse } from 'portscanner';
+import { findAPortNotInUse, checkPortStatus } from 'portscanner';
 
 
 const DEFAULT_BASE_PATH = '/wd/hub';
@@ -21,11 +21,24 @@ const PORT_ALLOCATION_GUARD = util.getLockFileGuard(path.resolve(os.tmpdir(), 'w
   timeout: 5,
   tryRecovery: true,
 });
+const TROUBLESHOOTING_LINK = 'https://github.com/appium/appium-windows-driver?tab=readme-ov-file#troubleshooting';
 
 class WADProxy extends JWProxy {
   /** @type {boolean|undefined} */
   didProcessExit;
 
+  async isListening() {
+    const url = this.getUrlForProxy('/status');
+    const parsedUrl = new URL(url);
+    const defaultPort = parsedUrl.protocol === 'https:' ? 443 : 80;
+    try {
+      await checkPortStatus(parseInt(parsedUrl.port, 10) || defaultPort, parsedUrl.hostname);
+      return true;
+    } catch {
+      return false;
+    }
+  }
+
   /**
    * @override
    */
@@ -183,6 +196,8 @@ export class WinAppDriver {
       }
     });
 
+    /** @type {Error | undefined} */
+    let lastError;
     try {
       await waitForCondition(async () => {
         try {
@@ -194,20 +209,32 @@ export class WinAppDriver {
           if (this.proxy?.didProcessExit) {
             throw new Error(err.message);
           }
+          lastError = err;
           return false;
         }
       }, {
         waitMs: STARTUP_TIMEOUT_MS,
         intervalMs: 1000,
       });
     } catch (e) {
-      if (/Condition unmet/.test(e.message)) {
-        throw new Error(
-          `WinAppDriver server is not listening within ${STARTUP_TIMEOUT_MS}ms timeout. ` +
-          `Make sure it could be started manually`
+      if (!lastError || this.proxy.didProcessExit) {
+        throw e;
+      }
+
+      const serverUrl = this.proxy.getUrlForProxy('/status');
+      let errorMessage = (
+        `WinAppDriver server '${executablePath}' is not listening at ${serverUrl} ` +
+        `after ${STARTUP_TIMEOUT_MS}ms timeout. Make sure it could be started manually.`
+      );
+      if (await this.proxy.isListening()) {
+        errorMessage = (
+          `WinAppDriver server '${executablePath}' is listening at ${serverUrl}, ` +
+          `but fails to respond with a proper status. It is an issue with the server itself. ` +
+          `Consider checking the troubleshooting guide at ${TROUBLESHOOTING_LINK}. ` +
+          `Original error: ${(lastError ?? e).message}`
         );
       }
-      throw e;
+      throw new Error(errorMessage);
     }
     const pid = this.process.proc?.pid;
     RUNNING_PROCESS_IDS.push(pid);
@@ -246,11 +273,20 @@ export class WinAppDriver {
 
     try {
       await this.proxy.command('/status', 'GET');
-    } catch {
-      throw new Error(
+    } catch (e) {
+      let errorMessage = (
         `WinAppDriver server is not listening at ${url}. ` +
         `Make sure it is running and the provided wadUrl is correct`
       );
+      if (await this.proxy.isListening()) {
+        errorMessage = (
+          `WinAppDriver server is listening at ${url}, but fails to respond with a proper status. ` +
+          `It is an issue with the server itself. ` +
+          `Consider checking the troubleshooting guide at ${TROUBLESHOOTING_LINK}. ` +
+          `Original error: ${e.message}`
+        );
+      }
+      throw new Error(errorMessage);
     }
   }