✨ **Enhance input validation and error handling across APIs**

- 🛠️ Refactored controllers to utilize `FiltersNumericIds` concern, ensuring secure numeric ID filtering and avoiding type-sensitive errors in queries.
- ➕ Added feature tests to validate robust input hardening for non-numeric or malformed query parameters (`user_id`, `selected[]`).
- 🔒 Introduced `PublicPropertyNotFoundException` handling in Livewire, returning 400 for invalid property probes and suppressing unnecessary log entries.
- ❌ Updated `MeetupEventController` to handle invalid date formats gracefully, aborting with a 400 response instead of 500.
- ✅ Expanded exception handling pipeline for enhanced resilience against malformed input, bot noise, and exploitable probes.

app/Http/Controllers/Api/CityController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api;
 
+use App\Http\Controllers\Api\Concerns\FiltersNumericIds;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Api\StoreCityRequest;
 use App\Http\Requests\Api\UpdateCityRequest;
@@ -20,6 +21,8 @@ use Symfony\Component\HttpFoundation\Response;
 #[Group(name: 'Stammdaten', weight: 5)]
 class CityController extends Controller
 {
+    use FiltersNumericIds;
+
     /**
      * Städte auflisten und durchsuchen
      *
@@ -40,8 +43,7 @@ class CityController extends Controller
             )
             ->when(
                 $request->exists('selected'),
-                fn (Builder $query) => $query->whereIn('id',
-                    $request->input('selected', [])),
+                fn (Builder $query) => $query->whereIn('id', $this->numericIds($request)),
                 fn (Builder $query) => $query->limit(10)
             )
             ->get();

app/Http/Controllers/Api/Concerns/FiltersNumericIds.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Http\Controllers\Api\Concerns;
+
+use Illuminate\Http\Request;
+
+trait FiltersNumericIds
+{
+    /**
+     * Reduziert einen Query-Parameter auf seine numerischen Werte als Integer-Liste.
+     *
+     * Schuetzt typsensitive whereIn('id', ...)-Klauseln vor nicht-numerischer Eingabe.
+     *
+     * @return array<int, int>
+     */
+    protected function numericIds(Request $request, string $key = 'selected'): array
+    {
+        return $request->collect($key)
+            ->filter(fn ($id) => is_numeric($id))
+            ->map(fn ($id) => (int) $id)
+            ->values()
+            ->all();
+    }
+}

app/Http/Controllers/Api/CourseController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api;
 
+use App\Http\Controllers\Api\Concerns\FiltersNumericIds;
 use App\Http\Controllers\Controller;
 use App\Models\Course;
 use Dedoc\Scramble\Attributes\ExcludeRouteFromDocs;
@@ -16,6 +17,8 @@ use Symfony\Component\HttpFoundation\Response;
 #[Group(name: 'Kurse', weight: 1)]
 class CourseController extends Controller
 {
+    use FiltersNumericIds;
+
     /**
      * Kurse auflisten und durchsuchen
      *
@@ -32,7 +35,7 @@ class CourseController extends Controller
             ->select('id', 'name')
             ->orderBy('name')
             ->when($request->has('user_id'),
-                fn (Builder $query) => $query->where('created_by', $request->user_id))
+                fn (Builder $query) => $query->where('created_by', $request->integer('user_id')))
             ->when(
                 $request->search,
                 fn (Builder $query) => $query
@@ -40,8 +43,7 @@ class CourseController extends Controller
             )
             ->when(
                 $request->exists('selected'),
-                fn (Builder $query) => $query->whereIn('id',
-                    $request->input('selected', [])),
+                fn (Builder $query) => $query->whereIn('id', $this->numericIds($request)),
                 fn (Builder $query) => $query->limit(10)
             )
             ->get()

app/Http/Controllers/Api/LecturerController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api;
 
+use App\Http\Controllers\Api\Concerns\FiltersNumericIds;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Api\StoreLecturerRequest;
 use App\Http\Requests\Api\UpdateLecturerRequest;
@@ -20,6 +21,8 @@ use Symfony\Component\HttpFoundation\Response;
 #[Group(name: 'Referenten', weight: 4)]
 class LecturerController extends Controller
 {
+    use FiltersNumericIds;
+
     /**
      * Referenten auflisten und durchsuchen
      *
@@ -32,8 +35,6 @@ class LecturerController extends Controller
         return Lecturer::query()
             ->select('id', 'name')
             ->orderBy('name')
-//                       ->when($request->has('user_id'),
-//                           fn(Builder $query) => $query->where('created_by', $request->user_id))
             ->when(
                 $request->search,
                 fn (Builder $query) => $query
@@ -41,8 +42,7 @@ class LecturerController extends Controller
             )
             ->when(
                 $request->exists('selected'),
-                fn (Builder $query) => $query->whereIn('id',
-                    $request->input('selected', [])),
+                fn (Builder $query) => $query->whereIn('id', $this->numericIds($request)),
                 fn (Builder $query) => $query->limit(10)
             )
             ->get()

app/Http/Controllers/Api/MeetupController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api;
 
+use App\Http\Controllers\Api\Concerns\FiltersNumericIds;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Api\StoreMeetupRequest;
 use App\Http\Requests\Api\UpdateMeetupRequest;
@@ -20,6 +21,8 @@ use Illuminate\Support\Facades\Gate;
 #[Group(name: 'Meetups', weight: 3)]
 class MeetupController extends Controller
 {
+    use FiltersNumericIds;
+
     #[ExcludeRouteFromDocs]
     public function ical()
     {
@@ -58,7 +61,7 @@ class MeetupController extends Controller
             )
             ->when(
                 $request->exists('selected'),
-                fn (Builder $query) => $query->whereIn('id', $request->input('selected', [])),
+                fn (Builder $query) => $query->whereIn('id', $this->numericIds($request)),
                 fn (Builder $query) => $query->limit(10),
             )
             ->get()

app/Http/Controllers/Api/MeetupEventController.php

@@ -8,6 +8,7 @@ use App\Http\Requests\Api\UpdateMeetupEventRequest;
 use App\Http\Resources\MeetupEventResource;
 use App\Models\MeetupEvent;
 use Carbon\Carbon;
+use Carbon\Exceptions\InvalidFormatException;
 use Dedoc\Scramble\Attributes\Group;
 use Dedoc\Scramble\Attributes\PathParameter;
 use Dedoc\Scramble\Attributes\Response as ResponseAttribute;
@@ -30,10 +31,15 @@ class MeetupEventController extends Controller
      * @return Collection<int, array<string, mixed>>
      */
     #[PathParameter(name: 'date', description: 'Optionales Datum (Y-m-d); filtert auf den Monat dieses Datums.', required: false, type: 'string')]
+    #[ResponseAttribute(status: 400, description: 'Das übergebene Datum ist nicht parsebar (erwartet wird Y-m-d).')]
     public function __invoke(?string $date = null): Collection
     {
         if ($date) {
-            $date = Carbon::parse($date);
+            try {
+                $date = Carbon::parse($date);
+            } catch (InvalidFormatException) {
+                abort(Response::HTTP_BAD_REQUEST, 'Ungültiges Datum. Erwartet wird das Format Y-m-d.');
+            }
         }
         $events = MeetupEvent::query()
             ->with([

app/Http/Controllers/Api/VenueController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api;
 
+use App\Http\Controllers\Api\Concerns\FiltersNumericIds;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Api\StoreVenueRequest;
 use App\Http\Requests\Api\UpdateVenueRequest;
@@ -20,6 +21,8 @@ use Symfony\Component\HttpFoundation\Response;
 #[Group(name: 'Stammdaten', weight: 5)]
 class VenueController extends Controller
 {
+    use FiltersNumericIds;
+
     /**
      * Veranstaltungsorte auflisten und durchsuchen
      *
@@ -42,8 +45,7 @@ class VenueController extends Controller
             )
             ->when(
                 $request->exists('selected'),
-                fn (Builder $query) => $query->whereIn('id',
-                    $request->input('selected', [])),
+                fn (Builder $query) => $query->whereIn('id', $this->numericIds($request)),
                 fn (Builder $query) => $query->limit(10)
             )
             ->get()

bootstrap/app.php

@@ -8,6 +8,7 @@ use Illuminate\Foundation\Configuration\Exceptions;
 use Illuminate\Foundation\Configuration\Middleware;
 use Illuminate\Http\Request;
 use Livewire\Exceptions\MethodNotFoundException;
+use Livewire\Exceptions\PublicPropertyNotFoundException;
 use Livewire\Features\SupportFileUploads\MissingFileUploadsTraitException;
 use Livewire\Features\SupportLifecycleHooks\DirectlyCallingLifecycleHooksNotAllowedException;
 use Livewire\Mechanisms\HandleComponents\CorruptComponentPayloadException;
@@ -85,7 +86,16 @@ return Application::configure(basePath: dirname(__DIR__))
             return false;
         };
 
-        $exceptions->report(function (Throwable $e) use ($isStaleLivewireAsset, $isStaleCompiledView, $isMissingFileUploadsTrait, $isLivewireExploitProbe) {
+        $isMalformedLivewirePropertyUpdate = function (Throwable $e): bool {
+            // Bots replay `livewire/update` with a mutated snapshot that sets public
+            // properties the target component never declared (e.g. `value` on `welcome`).
+            // Livewire rejects the update; in production this is pure bot noise, so we
+            // silence it. Locally we let it surface, so a genuinely undeclared property
+            // binding is still caught during development.
+            return $e instanceof PublicPropertyNotFoundException && ! app()->isLocal();
+        };
+
+        $exceptions->report(function (Throwable $e) use ($isStaleLivewireAsset, $isStaleCompiledView, $isMissingFileUploadsTrait, $isLivewireExploitProbe, $isMalformedLivewirePropertyUpdate) {
             if ($isStaleLivewireAsset($e, request())) {
                 return false;
             }
@@ -102,6 +112,10 @@ return Application::configure(basePath: dirname(__DIR__))
                 return false;
             }
 
+            if ($isMalformedLivewirePropertyUpdate($e)) {
+                return false;
+            }
+
             // Bots replay `/livewire/update` with a mutated snapshot whose HMAC
             // checksum no longer matches its [name, id, data]. Checksum::verify()
             // rejects these, so the rejection is the tamper signature, not an app
@@ -114,7 +128,7 @@ return Application::configure(basePath: dirname(__DIR__))
             return null;
         });
 
-        $exceptions->render(function (Throwable $e, Request $request) use ($isStaleLivewireAsset, $isStaleCompiledView, $isMissingFileUploadsTrait, $isLivewireExploitProbe) {
+        $exceptions->render(function (Throwable $e, Request $request) use ($isStaleLivewireAsset, $isStaleCompiledView, $isMissingFileUploadsTrait, $isLivewireExploitProbe, $isMalformedLivewirePropertyUpdate) {
             if ($isStaleLivewireAsset($e, $request)) {
                 return response('', 404);
             }
@@ -131,6 +145,10 @@ return Application::configure(basePath: dirname(__DIR__))
                 return response('', 400);
             }
 
+            if ($isMalformedLivewirePropertyUpdate($e)) {
+                return response('', 400);
+            }
+
             return null;
         });
     })->create();

tests/Feature/Api/ApiIndexInputHardeningTest.php

@@ -0,0 +1,29 @@
+<?php
+
+use App\Models\Course;
+use App\Models\Venue;
+
+it('drops non-numeric selected values on GET /api/courses instead of erroring', function () {
+    $course = Course::factory()->create();
+
+    $response = $this->getJson('/api/courses?selected[]='.$course->id.'&selected[]=foo');
+
+    $response->assertSuccessful();
+    expect(collect($response->json())->pluck('id')->all())->toBe([$course->id]);
+});
+
+it('casts a non-numeric user_id to an empty filter on GET /api/courses', function () {
+    Course::factory()->create();
+
+    $this->getJson('/api/courses?user_id=abc')
+        ->assertSuccessful()
+        ->assertJsonCount(0);
+});
+
+it('tolerates a non-array selected value on GET /api/venues without a 500', function () {
+    Venue::factory()->create();
+
+    $this->getJson('/api/venues?selected=foo')
+        ->assertSuccessful()
+        ->assertJsonCount(0);
+});

tests/Feature/Api/MeetupApiTest.php

@@ -94,3 +94,11 @@ it('filters /api/meetup-events by date when one is supplied', function () {
     $response->assertSuccessful();
     expect($response->json())->toBeArray()->not->toBeEmpty();
 });
+
+it('returns 400 instead of 500 when the date path segment is not parseable', function () {
+    $this->getJson('/api/meetup-events/'.urlencode('{date}'))
+        ->assertStatus(400);
+
+    $this->getJson('/api/meetup-events/not-a-date')
+        ->assertStatus(400);
+});

tests/Feature/LivewireExploitProbeTest.php

@@ -3,6 +3,7 @@
 use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\Route;
 use Livewire\Exceptions\MethodNotFoundException;
+use Livewire\Exceptions\PublicPropertyNotFoundException;
 use Livewire\Features\SupportLifecycleHooks\DirectlyCallingLifecycleHooksNotAllowedException;
 use Livewire\Mechanisms\HandleComponents\CorruptComponentPayloadException;
 
@@ -44,6 +45,28 @@ it('still surfaces genuine method-not-found bugs', function () {
     expect($this->get('/_test/livewire-real-method-not-found')->status())->not->toBe(400);
 });
 
+it('returns 400 for setting an undeclared public property instead of 500', function () {
+    Route::get('/_test/livewire-undeclared-property', function () {
+        throw new PublicPropertyNotFoundException('value', 'welcome');
+    });
+
+    expect($this->get('/_test/livewire-undeclared-property')->status())->toBe(400);
+});
+
+it('does not report undeclared-property probes to the logs', function () {
+    Log::spy();
+
+    Route::get('/_test/livewire-undeclared-property-log', function () {
+        throw new PublicPropertyNotFoundException('value', 'welcome');
+    });
+
+    $this->get('/_test/livewire-undeclared-property-log')->assertStatus(400);
+
+    Log::shouldNotHaveReceived('error');
+    Log::shouldNotHaveReceived('critical');
+    Log::shouldNotHaveReceived('emergency');
+});
+
 it('does not report corrupt Livewire snapshot payloads', function () {
     Log::spy();