Menus: Allow larger menus to be created in the Edit Menu screen.

In the Edit Menu screen, each menu item creates 11 form input elements. In menus with more than 71 menu items, often items after the 71st weren't saved. This was because PHP's runtime configuration `max_input_vars` default value is 1000. Large menus exceed this, so PHP didn't populate the `$_POST` superglobal for the latter menu items.

The entire form is now JSON-encoded into a single input which populates `$_POST` manually on form submission.

This was attempted previously in [36506] which was reverted in [36507]. Some form fields were not being slurped into the form's JSON representation, and it did not scale for a site with many posts. This approach fixes those problems.

Props ocean90, afercia.
See #14134.


git-svn-id: https://develop.svn.wordpress.org/trunk@36510 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/js/nav-menu.js

@@ -43,6 +43,7 @@ var wpNavMenu;
 
 			this.attachQuickSearchListeners();
 			this.attachThemeLocationsListeners();
+			this.attachMenuSaveSubmitListeners();
 
 			this.attachTabsPanelListeners();
 
@@ -834,6 +835,17 @@ var wpNavMenu;
 			});
 		},
 
+		attachMenuSaveSubmitListeners : function() {
+			/*
+			 * When a navigation menu is saved, store a JSON representation of all form data
+			 * in a single input to avoid PHP `max_input_vars` limitations. See #14134.
+			 */
+			$('#update-nav-menu').submit(function() {
+				var navMenuData = $('#update-nav-menu').serializeArray();
+				$('[name="nav-menu-data"]').val( JSON.stringify( navMenuData ) );
+			});
+		},
+
 		attachThemeLocationsListeners : function() {
 			var loc = $('#nav-menu-theme-locations'), params = {};
 			params.action = 'menu-locations-save';

src/wp-admin/nav-menus.php

@@ -49,6 +49,26 @@ $num_locations = count( array_keys( $locations ) );
 // Allowed actions: add, update, delete
 $action = isset( $_REQUEST['action'] ) ? $_REQUEST['action'] : 'edit';
 
+/*
+ * If a JSON blob of navigation menu data is found, expand it and inject it
+ * into `$_POST` to avoid PHP `max_input_vars` limitations. See #14134. 
+ */
+if ( isset( $_POST['nav-menu-data'] ) ) {
+	$data = json_decode( stripslashes( $_POST['nav-menu-data'] ) );
+	if ( ! is_null( $data ) && $data ) {
+		foreach ( $data as $post_input_data ) {
+			// For input names that are arrays (e.g. `menu-item-db-id[3]`), derive the array path keys via regex.
+			if ( preg_match( '#(.*)(?:\[(\d+)\])#', $post_input_data->name, $matches ) ) {
+				if ( empty( $_POST[$matches[1]] ) ) {
+					$_POST[$matches[1]] = array();
+				}
+				$_POST[$matches[1]][(int)$matches[2]] = $post_input_data->value;
+			} else {
+				$_POST[$post_input_data->name] = $post_input_data->value;
+			}
+		}
+	}
+}
 switch ( $action ) {
 	case 'add-menu-item':
 		check_admin_referer( 'add-menu_item', 'menu-settings-column-nonce' );
@@ -731,6 +751,7 @@ require_once( ABSPATH . 'wp-admin/admin-header.php' );
 		<div id="menu-management">
 			<form id="update-nav-menu" method="post" enctype="multipart/form-data">
 				<div class="menu-edit <?php if ( $add_new_screen ) echo 'blank-slate'; ?>">
+					<input type="hidden" name="nav-menu-data">
 					<?php
 					wp_nonce_field( 'closedpostboxes', 'closedpostboxesnonce', false );
 					wp_nonce_field( 'meta-box-order', 'meta-box-order-nonce', false );

src/wp-includes/script-loader.php

@@ -642,7 +642,7 @@ function wp_default_scripts( &$scripts ) {
 		) );
 
 		// Navigation Menus
-		$scripts->add( 'nav-menu', "/wp-admin/js/nav-menu$suffix.js", array( 'jquery-ui-sortable', 'jquery-ui-draggable', 'jquery-ui-droppable', 'wp-lists', 'postbox' ) );
+		$scripts->add( 'nav-menu', "/wp-admin/js/nav-menu$suffix.js", array( 'jquery-ui-sortable', 'jquery-ui-draggable', 'jquery-ui-droppable', 'wp-lists', 'postbox', 'json2' ) );
 		did_action( 'init' ) && $scripts->localize( 'nav-menu', 'navMenuL10n', array(
 			'noResultsFound' => __( 'No results found.' ),
 			'warnDeleteMenu' => __( "You are about to permanently delete this menu. \n 'Cancel' to stop, 'OK' to delete." ),