API CHANGE: Added GridField_URLHandler component interface.

docs/en/topics/grid-field.md

@@ -194,11 +194,55 @@ A `GridField_DataManipulator` component can modify the data list.  For example,
 
  * **`getManipulatedData(GridField $gridField, SS_List $dataList)`:** Given this grid's data list, return an updated list to be used with this grid.
 
-### GridField_URLProvider
+### GridField_URLHandler
 
-**COMING SOON**
+Sometimes an action isn't enough: you need to provide additional support URLs for the grid.  These URLs may return user-visible content, for example a pop-up form for editing a record's details, or they may be support URLs for front-end functionality, for example a URL that will return JSON-formatted data for a javascript grid control.
 
-This interface isn't implemented yet, but will let you define a component that provides additional support URLs for the grid.  These URLs may return user-visible content, for example a pop-up form for editing a record's details, or they may be support URLs for front-end functionality, for example a URL that will return JSON-formatted data for a javascript grid control.
+To build these components, you should implement the `GridField_URLHandler` interface.  It only specifies one method: `getURLHandlers($gridField)`.  This method should return an array similar to the `RequestHandler::$url_handlers` static.  The action handlers should also be defined on the component; they will be passed `$gridField` and `$request`.
+
+Here is an example in full.  The actual implementation of the view and edit forms isn't included.
+
+	:::php
+	/**
+	 * Provides view and edit forms at GridField-specific URLs.  These can be placed into pop-ups by an appropriate front-end.
+	 * 
+	 * The URLs provided will be off the following form:
+	 *  - <FormURL>/field/<GridFieldName>/item/<RecordID>
+	 *  - <FormURL>/field/<GridFieldName>/item/<RecordID>/edit
+	 */
+	class GridFieldPopupForms implements GridField_URLHandler {
+		function getURLHandlers($gridField) {
+			return array(
+				'item/$ID' => 'handleItem',
+			);
+		}
+
+		function handleItem($gridField, $request) {
+			$record = $gridField->getList()->byId($request->param("ID"));
+			return new GridFieldPopupForm_ItemRequest($gridField, $this, $record);
+		}
+	}
+
+	class GridFieldPopupForm_ItemRequest extends RequestHandler {
+		protected $gridField;
+		protected $component;
+		protected $record;
+
+		function __construct($gridField, $component, $record) {
+			$this->gridField = $gridField;
+			$this->component = $gridField;
+			$this->record = $record;
+			parent::__construct();
+		}
+
+		function index() {
+			echo "view form for record #" . $record->ID;
+		}
+
+		function edit() {
+			echo "edit form for record #" . $record->ID;
+		}
+	}
 
 ## Other tools
 

forms/gridfield/GridField.php

@@ -461,6 +461,74 @@ class GridField extends FormField {
 		}
 		throw new InvalidArgumentException("Can't handle action '$actionName'");
 	}
+	
+	/**
+	 * Custom request handler that will check component handlers before proceeding to the default implementation.
+	 * 
+	 * @todo There is too much code copied from RequestHandler here.
+	 */
+	function handleRequest(SS_HTTPRequest $request, DataModel $model) {
+		if($this->brokenOnConstruct) {
+			user_error("parent::__construct() needs to be called on {$handlerClass}::__construct()", E_USER_WARNING);
+		}
+
+		$this->request = $request;
+		$this->setModel($model);
+		
+		///
+
+		foreach($this->components as $component) {
+			if(!($component instanceof GridField_URLHandler)) {
+				continue;
+			}
+			
+			$urlHandlers = $component->getURLHandlers($this);
+			
+			if($urlHandlers) foreach($urlHandlers as $rule => $action) {
+				if($params = $request->match($rule, true)) {
+					// Actions can reference URL parameters, eg, '$Action/$ID/$OtherID' => '$Action',
+					if($action[0] == '$') $action = $params[substr($action,1)];
+					if(!method_exists($component, 'checkAccessAction') || $component->checkAccessAction($action)) {
+						if(!$action) {
+							$action = "index";
+						} else if(!is_string($action)) {
+							throw new LogicException("Non-string method name: " . var_export($action, true));
+						}
+
+						try {
+							$result = $component->$action($this, $request);
+						} catch(SS_HTTPResponse_Exception $responseException) {
+							$result = $responseException->getResponse();
+						}
+
+						if($result instanceof SS_HTTPResponse && $result->isError()) {
+							return $result;
+						}
+
+						if($this !== $result && !$request->isEmptyPattern($rule) && is_object($result) && $result instanceof RequestHandler) {
+							$returnValue = $result->handleRequest($request, $model);
+
+							if(is_array($returnValue)) {
+								throw new LogicException("GridField_URLHandler handlers can't return arrays");
+							}
+
+							return $returnValue;
+
+						// If we return some other data, and all the URL is parsed, then return that
+						} else if($request->allParsed()) {
+							return $result;
+
+						// But if we have more content on the URL and we don't know what to do with it, return an error.
+						} else {
+							return $this->httpError(404, "I can't handle sub-URLs of a " . get_class($result) . " object.");
+						}
+					}
+				}
+			}
+		}
+		
+		return parent::handleRequest($request, $model);
+	}
 }
 
 

forms/gridfield/GridFieldComponent.php

@@ -41,4 +41,15 @@ interface GridField_DataManipulator extends GridFieldComponent {
 	 * Return the new DataList. 
 	 */
 	function getManipulatedData(GridField $gridField, SS_List $dataList);
+}
+
+interface GridField_URLHandler extends GridFieldComponent {
+	/**
+	 * Return URLs to be handled by this grid field, in an array the same form as $url_handlers.
+	 * 
+	 * Handler methods will be called on the component, rather than the grid field.
+	 * 
+	 * The handlers will be passed two arguments, $gridField and $request
+	 */
+	function getURLHandlers($gridField);
 }