DataTableAction query parameter can be Closure. (#71)

* DataTableAction query parameter can be Closure.

* Update README with DataTableAction query example.

* Add description about v1.1.3 to CHANGELOG.

Author: alxlnk

CHANGELOG.md

@@ -2,6 +2,10 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## v1.1.3
+### Added
+- `DataTableAction` `query` parameter can be `Closure`
+
 ## v1.1.2
 ### Added
 - Support for bootstrap 4/5 (autodetect required bootstrap version)
@@ -46,4 +50,4 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed 
 - Move DataTable options to protected array. Add __set and __get methods.
 
-[#52]: https://github.com/NullRefExcep/yii2-datatables/issues/52
+[#52]: https://github.com/NullRefExcep/yii2-datatables/issues/52

README.md

@@ -286,6 +286,17 @@ public function actions()
 
 If you need to get some relation data you can call `join` or similar methods from `$query` in `applyFilter` closure.
 
+You may also specify a closure for `query` in `DataTableAction` config if you need complex query like in the following code:
+```php
+/** ... */
+'query' => function() {
+    $calculatedValue = calculate_value_for_query();
+    
+    return Model::find()->where(['calculated_value' => $calculatedValue]);
+},
+/** ... */
+```
+
 And add options to widget: 
 
 ```php

composer.json

@@ -28,6 +28,12 @@
             "email": "[email protected]",
             "homepage": "https://github.com/Radon8472",
             "role": "Contributor"
+        },
+        {
+            "name": "Oleksandr Lynnyk",
+            "email": "[email protected]",
+            "homepage": "https://github.com/alxlnk",
+            "role": "Contributor"
         }
     ],
     "minimum-stability": "stable",

src/DataTableAction.php

@@ -8,6 +8,7 @@
 namespace nullref\datatable;
 
 
+use Closure;
 use Yii;
 use yii\base\Action;
 use yii\base\InvalidConfigException;
@@ -37,7 +38,7 @@ class DataTableAction extends Action
     public $requestMethod = self::REQUEST_METHOD_GET;
 
     /**
-     * @var ActiveQuery
+     * @var ActiveQuery|Closure
      */
     public $query;
 
@@ -91,6 +92,10 @@ public function init()
             throw new InvalidConfigException(get_class($this) . '::$query must be set.');
         }
 
+        if ($this->query instanceof Closure) {
+            $this->query = call_user_func($this->query);
+        }
+
         if ($this->formatData === null) {
             $this->formatData = function ($query, $columns) {
                 $rows = [];
@@ -249,4 +254,4 @@ public function formatResponse($response)
 
         return $response;
     }
-} 
+}