monitoring: Add DataView::$requiresFilter

refs #9606

modules/monitoring/library/Monitoring/DataView/DataView.php

@@ -11,6 +11,7 @@ use Icinga\Data\FilterColumns;
 use Icinga\Data\PivotTable;
 use Icinga\Data\QueryInterface;
 use Icinga\Data\SortRules;
+use Icinga\Exception\Http\HttpBadRequestException;
 use Icinga\Exception\QueryException;
 use Icinga\Module\Monitoring\Backend\Ido\Query\IdoQuery;
 use Icinga\Module\Monitoring\Backend\MonitoringBackend;
@@ -40,6 +41,13 @@ abstract class DataView implements QueryInterface, SortRules, FilterColumns, Ite
      */
     protected $filterColumns;
 
+    /**
+     * Whether the data view requires a filter
+     *
+     * @var bool
+     */
+    protected $requiresFilter = false;
+
     /**
      * Create a new view
      *
@@ -188,6 +196,29 @@ abstract class DataView implements QueryInterface, SortRules, FilterColumns, Ite
         return in_array($column, $this->getFilterColumns());
     }
 
+    /**
+     * Get whether the data view requires a filter
+     *
+     * @return bool
+     */
+    public function getRequiresFilter()
+    {
+        return $this->requiresFilter;
+    }
+
+    /**
+     * Set whether the data view requires a filter
+     *
+     * @param   bool $requiresFilter
+     *
+     * @return  $this
+     */
+    public function setRequiresFilter($requiresFilter = true)
+    {
+        $this->requiresFilter = (bool) $requiresFilter;
+        return $this;
+    }
+
     /**
      * Return all filter columns with their optional label as key
      *
@@ -638,7 +669,12 @@ abstract class DataView implements QueryInterface, SortRules, FilterColumns, Ite
     public function handleRequest(Request $request)
     {
         $params = $request->getUrl()->getParams();
-        $this->applyFilter(Filter::fromQuerystring((string) $params));
+        $filter = Filter::fromQuerystring((string) $params);
+        /** @var Filter $filter */
+        if ($this->getRequiresFilter() && $filter->isEmpty()) {
+            throw new HttpBadRequestException('Filter must not be empty');
+        }
+        $this->applyFilter($filter);
         return $this;
     }
 }