1<?php
2/**
3 * Nav Menu API: Walker_Nav_Menu class
4 *
5 * @package WordPress
6 * @subpackage Nav_Menus
7 * @since 4.6.0
8 */
9
10/**
11 * Core class used to implement an HTML list of nav menu items.
12 *
13 * @since 3.0.0
14 *
15 * @see Walker
16 */
17class Walker_Nav_Menu extends Walker {
18 /**
19 * What the class handles.
20 *
21 * @since 3.0.0
22 * @var string
23 *
24 * @see Walker::$tree_type
25 */
26 public $tree_type = array( 'post_type', 'taxonomy', 'custom' );
27
28 /**
29 * Database fields to use.
30 *
31 * @since 3.0.0
32 * @todo Decouple this.
33 * @var string[]
34 *
35 * @see Walker::$db_fields
36 */
37 public $db_fields = array(
38 'parent' => 'menu_item_parent',
39 'id' => 'db_id',
40 );
41
42 /**
43 * The URL to the privacy policy page.
44 *
45 * @since 6.8.0
46 * @var string
47 */
48 private $privacy_policy_url;
49
50 /**
51 * Constructor.
52 *
53 * @since 6.8.0
54 */
55 public function __construct() {
56 $this->privacy_policy_url = get_privacy_policy_url();
57 }
58
59 /**
60 * Starts the list before the elements are added.
61 *
62 * @since 3.0.0
63 *
64 * @see Walker::start_lvl()
65 *
66 * @param string $output Used to append additional content (passed by reference).
67 * @param int $depth Depth of menu item. Used for padding.
68 * @param stdClass $args An object of wp_nav_menu() arguments.
69 */
70 public function start_lvl( &$output, $depth = 0, $args = null ) {
71 if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
72 $t = '';
73 $n = '';
74 } else {
75 $t = "\t";
76 $n = "\n";
77 }
78 $indent = str_repeat( $t, $depth );
79
80 // Default class.
81 $classes = array( 'sub-menu' );
82
83 /**
84 * Filters the CSS class(es) applied to a menu list element.
85 *
86 * @since 4.8.0
87 *
88 * @param string[] $classes Array of the CSS classes that are applied to the menu `<ul>` element.
89 * @param stdClass $args An object of `wp_nav_menu()` arguments.
90 * @param int $depth Depth of menu item. Used for padding.
91 */
92 $class_names = implode( ' ', apply_filters( 'nav_menu_submenu_css_class', $classes, $args, $depth ) );
93
94 $atts = array();
95 $atts['class'] = ! empty( $class_names ) ? $class_names : '';
96
97 /**
98 * Filters the HTML attributes applied to a menu list element.
99 *
100 * @since 6.3.0
101 *
102 * @param array $atts {
103 * The HTML attributes applied to the `<ul>` element, empty strings are ignored.
104 *
105 * @type string $class HTML CSS class attribute.
106 * }
107 * @param stdClass $args An object of `wp_nav_menu()` arguments.
108 * @param int $depth Depth of menu item. Used for padding.
109 */
110 $atts = apply_filters( 'nav_menu_submenu_attributes', $atts, $args, $depth );
111 $attributes = $this->build_atts( $atts );
112
113 $output .= "{$n}{$indent}<ul{$attributes}>{$n}";
114 }
115
116 /**
117 * Ends the list of after the elements are added.
118 *
119 * @since 3.0.0
120 *
121 * @see Walker::end_lvl()
122 *
123 * @param string $output Used to append additional content (passed by reference).
124 * @param int $depth Depth of menu item. Used for padding.
125 * @param stdClass $args An object of wp_nav_menu() arguments.
126 */
127 public function end_lvl( &$output, $depth = 0, $args = null ) {
128 if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
129 $t = '';
130 $n = '';
131 } else {
132 $t = "\t";
133 $n = "\n";
134 }
135 $indent = str_repeat( $t, $depth );
136 $output .= "$indent</ul>{$n}";
137 }
138
139 /**
140 * Starts the element output.
141 *
142 * @since 3.0.0
143 * @since 4.4.0 The {@see 'nav_menu_item_args'} filter was added.
144 * @since 5.9.0 Renamed `$item` to `$data_object` and `$id` to `$current_object_id`
145 * to match parent class for PHP 8 named parameter support.
146 * @since 6.7.0 Removed redundant title attributes.
147 *
148 * @see Walker::start_el()
149 *
150 * @param string $output Used to append additional content (passed by reference).
151 * @param WP_Post $data_object Menu item data object.
152 * @param int $depth Depth of menu item. Used for padding.
153 * @param stdClass $args An object of wp_nav_menu() arguments.
154 * @param int $current_object_id Optional. ID of the current menu item. Default 0.
155 */
156 public function start_el( &$output, $data_object, $depth = 0, $args = null, $current_object_id = 0 ) {
157 // Restores the more descriptive, specific name for use within this method.
158 $menu_item = $data_object;
159
160 if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
161 $t = '';
162 $n = '';
163 } else {
164 $t = "\t";
165 $n = "\n";
166 }
167 $indent = ( $depth ) ? str_repeat( $t, $depth ) : '';
168
169 $classes = empty( $menu_item->classes ) ? array() : (array) $menu_item->classes;
170 $classes[] = 'menu-item-' . $menu_item->ID;
171
172 /**
173 * Filters the arguments for a single nav menu item.
174 *
175 * @since 4.4.0
176 *
177 * @param stdClass $args An object of wp_nav_menu() arguments.
178 * @param WP_Post $menu_item Menu item data object.
179 * @param int $depth Depth of menu item. Used for padding.
180 */
181 $args = apply_filters( 'nav_menu_item_args', $args, $menu_item, $depth );
182
183 /**
184 * Filters the CSS classes applied to a menu item's list item element.
185 *
186 * @since 3.0.0
187 * @since 4.1.0 The `$depth` parameter was added.
188 *
189 * @param string[] $classes Array of the CSS classes that are applied to the menu item's `<li>` element.
190 * @param WP_Post $menu_item The current menu item object.
191 * @param stdClass $args An object of wp_nav_menu() arguments.
192 * @param int $depth Depth of menu item. Used for padding.
193 */
194 $class_names = implode( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $menu_item, $args, $depth ) );
195
196 /**
197 * Filters the ID attribute applied to a menu item's list item element.
198 *
199 * @since 3.0.1
200 * @since 4.1.0 The `$depth` parameter was added.
201 *
202 * @param string $menu_item_id The ID attribute applied to the menu item's `<li>` element.
203 * @param WP_Post $menu_item The current menu item.
204 * @param stdClass $args An object of wp_nav_menu() arguments.
205 * @param int $depth Depth of menu item. Used for padding.
206 */
207 $id = apply_filters( 'nav_menu_item_id', 'menu-item-' . $menu_item->ID, $menu_item, $args, $depth );
208
209 $li_atts = array();
210 $li_atts['id'] = ! empty( $id ) ? $id : '';
211 $li_atts['class'] = ! empty( $class_names ) ? $class_names : '';
212
213 /**
214 * Filters the HTML attributes applied to a menu's list item element.
215 *
216 * @since 6.3.0
217 *
218 * @param array $li_atts {
219 * The HTML attributes applied to the menu item's `<li>` element, empty strings are ignored.
220 *
221 * @type string $class HTML CSS class attribute.
222 * @type string $id HTML id attribute.
223 * }
224 * @param WP_Post $menu_item The current menu item object.
225 * @param stdClass $args An object of wp_nav_menu() arguments.
226 * @param int $depth Depth of menu item. Used for padding.
227 */
228 $li_atts = apply_filters( 'nav_menu_item_attributes', $li_atts, $menu_item, $args, $depth );
229 $li_attributes = $this->build_atts( $li_atts );
230
231 $output .= $indent . '<li' . $li_attributes . '>';
232
233 /** This filter is documented in wp-includes/post-template.php */
234 $title = apply_filters( 'the_title', $menu_item->title, $menu_item->ID );
235
236 // Save filtered value before filtering again.
237 $the_title_filtered = $title;
238
239 /**
240 * Filters a menu item's title.
241 *
242 * @since 4.4.0
243 *
244 * @param string $title The menu item's title.
245 * @param WP_Post $menu_item The current menu item object.
246 * @param stdClass $args An object of wp_nav_menu() arguments.
247 * @param int $depth Depth of menu item. Used for padding.
248 */
249 $title = apply_filters( 'nav_menu_item_title', $title, $menu_item, $args, $depth );
250
251 $atts = array();
252 $atts['target'] = ! empty( $menu_item->target ) ? $menu_item->target : '';
253 $atts['rel'] = ! empty( $menu_item->xfn ) ? $menu_item->xfn : '';
254
255 if ( ! empty( $menu_item->url ) ) {
256 if ( $this->privacy_policy_url === $menu_item->url ) {
257 $atts['rel'] = empty( $atts['rel'] ) ? 'privacy-policy' : $atts['rel'] . ' privacy-policy';
258 }
259
260 $atts['href'] = $menu_item->url;
261 } else {
262 $atts['href'] = '';
263 }
264
265 $atts['aria-current'] = $menu_item->current ? 'page' : '';
266
267 // Add title attribute only if it does not match the link text (before or after filtering).
268 if ( ! empty( $menu_item->attr_title )
269 && trim( strtolower( $menu_item->attr_title ) ) !== trim( strtolower( $menu_item->title ) )
270 && trim( strtolower( $menu_item->attr_title ) ) !== trim( strtolower( $the_title_filtered ) )
271 && trim( strtolower( $menu_item->attr_title ) ) !== trim( strtolower( $title ) )
272 ) {
273 $atts['title'] = $menu_item->attr_title;
274 } else {
275 $atts['title'] = '';
276 }
277
278 /**
279 * Filters the HTML attributes applied to a menu item's anchor element.
280 *
281 * @since 3.6.0
282 * @since 4.1.0 The `$depth` parameter was added.
283 *
284 * @param array $atts {
285 * The HTML attributes applied to the menu item's `<a>` element, empty strings are ignored.
286 *
287 * @type string $title Title attribute.
288 * @type string $target Target attribute.
289 * @type string $rel The rel attribute.
290 * @type string $href The href attribute.
291 * @type string $aria-current The aria-current attribute.
292 * }
293 * @param WP_Post $menu_item The current menu item object.
294 * @param stdClass $args An object of wp_nav_menu() arguments.
295 * @param int $depth Depth of menu item. Used for padding.
296 */
297 $atts = apply_filters( 'nav_menu_link_attributes', $atts, $menu_item, $args, $depth );
298 $attributes = $this->build_atts( $atts );
299
300 $item_output = $args->before;
301 $item_output .= '<a' . $attributes . '>';
302 $item_output .= $args->link_before . $title . $args->link_after;
303 $item_output .= '</a>';
304 $item_output .= $args->after;
305
306 /**
307 * Filters a menu item's starting output.
308 *
309 * The menu item's starting output only includes `$args->before`, the opening `<a>`,
310 * the menu item's title, the closing `</a>`, and `$args->after`. Currently, there is
311 * no filter for modifying the opening and closing `<li>` for a menu item.
312 *
313 * @since 3.0.0
314 *
315 * @param string $item_output The menu item's starting HTML output.
316 * @param WP_Post $menu_item Menu item data object.
317 * @param int $depth Depth of menu item. Used for padding.
318 * @param stdClass $args An object of wp_nav_menu() arguments.
319 */
320 $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $menu_item, $depth, $args );
321 }
322
323 /**
324 * Ends the element output, if needed.
325 *
326 * @since 3.0.0
327 * @since 5.9.0 Renamed `$item` to `$data_object` to match parent class for PHP 8 named parameter support.
328 *
329 * @see Walker::end_el()
330 *
331 * @param string $output Used to append additional content (passed by reference).
332 * @param WP_Post $data_object Menu item data object. Not used.
333 * @param int $depth Depth of page. Not Used.
334 * @param stdClass $args An object of wp_nav_menu() arguments.
335 */
336 public function end_el( &$output, $data_object, $depth = 0, $args = null ) {
337 if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
338 $t = '';
339 $n = '';
340 } else {
341 $t = "\t";
342 $n = "\n";
343 }
344 $output .= "</li>{$n}";
345 }
346
347 /**
348 * Builds a string of HTML attributes from an array of key/value pairs.
349 * Empty values are ignored.
350 *
351 * @since 6.3.0
352 *
353 * @param array $atts Optional. An array of HTML attribute key/value pairs. Default empty array.
354 * @return string A string of HTML attributes.
355 */
356 protected function build_atts( $atts = array() ) {
357 $attribute_string = '';
358 foreach ( $atts as $attr => $value ) {
359 if ( false !== $value && '' !== $value && is_scalar( $value ) ) {
360 $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
361 $attribute_string .= ' ' . $attr . '="' . $value . '"';
362 }
363 }
364 return $attribute_string;
365 }
366}
367