Fix Twill custom error view and ability to extend handler

Twill uses it's own internal exception handler for controllers extending `A17\Twill\Http\Admin\Controller` and `A17\Twill\Http\Front\Controller`, to support unauthenticated requests redirection, custom error views and custom validation error responses.

To be able to render custom exceptions or report them to an external service on route that is mapped to Twill's controller, it is necessary to disable `twill.bind_exception_handler`. Your Laravel handler can then extend Twill's internal handler.

The reasoning behind assigning a custom handler to the FrontController is to be able to redirect unauthenticated requests to `/admin-preview` routes that are registered by the `showWithPreview` route macro. This is the url showing in the CMS permalink when a record is still a draft. Not many Twill users are leveraging this frontend tooling, but it exists, so wanted to provide the rationale behind all this.

This commit is resolving issue for users that were previously extending the handler for the reasons explained above, as well as making sure custom Twill errors view are automatically in use on the admin routes.

src/Exceptions/Handler.php

@@ -3,9 +3,12 @@
 namespace A17\Twill\Exceptions;
 
 use Illuminate\Auth\AuthenticationException;
-use App\Exceptions\Handler as ExceptionHandler;
+use Illuminate\Foundation\Exceptions\Handler as ExceptionHandler;
 use Illuminate\Support\Facades\Route;
+use Illuminate\Support\Facades\Request;
+use Illuminate\Support\Str;
 use Illuminate\Validation\ValidationException;
+use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
 
 class Handler extends ExceptionHandler
 {
@@ -23,6 +26,23 @@ protected function unauthenticated($request, AuthenticationException $exception)
             : redirect()->guest($exception->redirectTo() ?? route('admin.login', Route::current()->parameters()));
     }
 
+    /**
+     * Get the view used to render HTTP exceptions.
+     *
+     * @param  \Symfony\Component\HttpKernel\Exception\HttpExceptionInterface  $e
+     * @return string
+     */
+    protected function getHttpExceptionView(HttpExceptionInterface $e)
+    {
+        $usesAdminPath = !empty(config('twill.admin_app_path'));
+        $adminAppUrl = parse_url(config('twill.admin_app_url'));
+
+        $isSubdomainAdmin = !$usesAdminPath && $adminAppUrl['host'] == Request::getHost();
+        $isSubdirectoryAdmin = $usesAdminPath && Str::starts_with(Request::path(), config('twill.admin_app_path'));
+
+        return $this->getTwillErrorView($e->getStatusCode(), !($isSubdomainAdmin || $isSubdirectoryAdmin));
+    }
+
     /**
      * Get the Twill error view used to render a specified HTTP status code.
      *
@@ -32,10 +52,14 @@ protected function unauthenticated($request, AuthenticationException $exception)
     protected function getTwillErrorView($statusCode, $frontend = false)
     {
         if ($frontend) {
-            return config('twill.frontend.views_path') . ".errors.$statusCode";
+            $view = config('twill.frontend.views_path') . ".errors.$statusCode";
+
+            return view()->exists($view)? $view : "errors::{$statusCode}";
         }
 
-        return view()->exists("admin.errors.$statusCode") ? "admin.errors.$statusCode" : "twill::errors.$statusCode";
+        $view = "admin.errors.$statusCode";
+
+        return view()->exists($view) ? $view : "twill::errors.$statusCode";
     }
 
     protected function invalidJson($request, ValidationException $exception)

tests/integration/TestCase.php

@@ -122,8 +122,6 @@ public function setUp(): void
         $this->copyBlocks();
 
         $this->installTwill();
-
-        $this->ensureAppExceptionHandlerExists();
     }
 
     /**
@@ -763,21 +761,4 @@ public function migrate()
     public function loadConfig()
     {
     }
-
-    public function ensureAppExceptionHandlerExists()
-    {
-        $stubPath = __DIR__.'/../../tests/stubs/classes/AppExceptionHandler.php';
-
-        $filePath = __DIR__.'/../../vendor/orchestra/testbench-core/laravel/app/Exceptions/Handler.php';
-
-        $dir = dirname($filePath);
-
-        if (!file_exists($filePath)) {
-            if (!file_exists($dir)) {
-                mkdir($dir, 0755, true);
-            }
-
-            file_put_contents($filePath, file_get_contents($stubPath));
-        }
-    }
 }