Add support for filtering allocations to determine if they're assigned or not; closes pterodactyl#3872

Author: DaneEveritt

app/Http/Controllers/Api/Application/Nodes/AllocationController.php

@@ -5,6 +5,9 @@
 use Pterodactyl\Models\Node;
 use Illuminate\Http\JsonResponse;
 use Pterodactyl\Models\Allocation;
+use Spatie\QueryBuilder\QueryBuilder;
+use Spatie\QueryBuilder\AllowedFilter;
+use Illuminate\Database\Eloquent\Builder;
 use Pterodactyl\Services\Allocations\AssignmentService;
 use Pterodactyl\Services\Allocations\AllocationDeletionService;
 use Pterodactyl\Transformers\Api\Application\AllocationTransformer;
@@ -43,7 +46,20 @@ public function __construct(
      */
     public function index(GetAllocationsRequest $request, Node $node): array
     {
-        $allocations = $node->allocations()->paginate($request->query('per_page') ?? 50);
+        $allocations = QueryBuilder::for($node->allocations())
+            ->allowedFilters([
+                AllowedFilter::exact('ip'),
+                AllowedFilter::exact('port'),
+                'ip_alias',
+                AllowedFilter::callback('server_id', function (Builder $builder, $value) {
+                    if (empty($value) || is_bool($value) || !ctype_digit((string) $value)) {
+                        return $builder->whereNull('server_id');
+                    }
+
+                    return $builder->where('server_id', $value);
+                }),
+            ])
+            ->paginate($request->query('per_page') ?? 50);
 
         return $this->fractal->collection($allocations)
             ->transformWith($this->getTransformer(AllocationTransformer::class))