API CHANGE: Added GridFieldExporter, a GridField component that adds export functionality, and added it to the security admin.

admin/code/SecurityAdmin.php

@@ -108,6 +108,7 @@ class SecurityAdmin extends LeftAndMain implements PermissionProvider {
 	function RootForm() {
 		$config = new GridFieldConfig_Base(25);
 		$config->addComponent(new GridFieldPopupForms($this, 'RootForm'));
+		$config->addComponent(new GridFieldExporter());
 		$memberList = new GridField('Members', 'All members', DataList::create('Member'), $config);
 		
 		$fields = new FieldList(

forms/gridfield/GridFieldExporter.php

@@ -0,0 +1,95 @@
+<?php
+
+/**
+ * Adds an "Export list" button to the bottom of a GridField.
+ * 
+ * WARNING: This is experimental and its API is subject to change.  Feel free to use it as long as you are happy of
+ * refactoring your code in the future.
+ */
+
+class GridFieldExporter implements GridField_HTMLProvider, GridField_ActionProvider, GridField_URLHandler {
+	protected $exportColumns;
+	protected $csvSeparator = ",";
+	protected $csvHasHeader = true;
+
+	public function __construct($exportColumns = null) {
+		$this->exportColumns = $exportColumns;
+	}
+
+	/**
+	 * Place the export button in a <p> tag below the field
+	 */
+	public function getHTMLFragments($gridField) {
+		$button = new GridField_Action($gridField, 'export', 'Export to CSV', 'export', null);
+		return array(
+			'after' => '<p>' . htmlentities($button->Field()) . '</p>',
+		);
+	}
+
+	/**
+	 * export is an action button
+	 */
+	public function getActions($gridField) {
+		return array('export');
+	}
+
+	function handleAction(GridField $gridField, $actionName, $arguments, $data) {
+		if($actionName == 'export') {
+			return $this->handleExport($gridField);
+		}
+	}
+
+	/**
+	 * it is also a URL
+	 */
+	function getURLHandlers($gridField) {
+		return array(
+			'export' => 'handleExport',
+		);
+	}
+
+	/**
+	 * Handle the export, for both the action button and the URL
+ 	 */
+	public function handleExport($gridField, $request = null) {
+		$now = Date("d-m-Y-H-i");
+		$fileName = "export-$now.csv";
+
+		if($fileData = $this->generateExportFileData($gridField)){
+			return SS_HTTPRequest::send_file($fileData, $fileName);
+		}
+	}
+
+	/**
+	 * Export core.
+ 	 */
+	function generateExportFileData($gridField) {
+		$separator = $this->csvSeparator;
+		$csvColumns = ($this->exportColumns) ? $this->exportColumns : $gridField->getDisplayFields();
+		$fileData = '';
+		$columnData = array();
+		$fieldItems = new ArrayList();
+		
+		if($this->csvHasHeader) {
+			$fileData .= "\"" . implode("\"{$separator}\"", array_values($csvColumns)) . "\"";
+			$fileData .= "\n";
+		}
+
+		$items = $gridField->getList();
+		foreach($items as $item) {
+			$columnData = array();
+			foreach($csvColumns as $columnSource => $columnHeader) {
+				$value = $item->$columnSource;
+				$value = str_replace(array("\r", "\n"), "\n", $value);
+				$columnData[] = '"' . str_replace('"', '\"', $value) . '"';
+			}
+			$fileData .= implode($separator, $columnData);
+			$fileData .= "\n";
+
+			$item->destroy();
+		}
+			
+		return $fileData;
+	}
+	
+}

security/Group.php

@@ -64,6 +64,7 @@ class Group extends DataObject {
 		
 		$config = new GridFieldConfig_ManyManyEditor('FirstName', false, 20);
 		$config->addComponent(new GridFieldPopupForms(Controller::curr(), 'EditForm'));
+		$config->addComponent(new GridFieldExporter());
 		$memberList = new GridField('Members','Members', $this->Members(), $config);
 
 		// @todo Implement permission checking on GridField