1 | <?php |
---|
2 | /* |
---|
3 | Plugin Name: Custom Metaboxes for Core |
---|
4 | |
---|
5 | */ |
---|
6 | |
---|
7 | class WP_Meta_Box { |
---|
8 | /** |
---|
9 | * The screen where the meta box will be shown. |
---|
10 | */ |
---|
11 | public $screen; |
---|
12 | |
---|
13 | /** |
---|
14 | * A unique slug to allow multiple meta boxes of the same class |
---|
15 | * to exist on the same screen. |
---|
16 | */ |
---|
17 | public $slug; |
---|
18 | |
---|
19 | /** |
---|
20 | * A unique identifier for the meta box. |
---|
21 | * |
---|
22 | * A string composed from the meta box class, screen, and slug. |
---|
23 | */ |
---|
24 | public $unique_id; |
---|
25 | |
---|
26 | /** |
---|
27 | * Arguments passed to the meta box constructor. |
---|
28 | */ |
---|
29 | public $args; |
---|
30 | |
---|
31 | /** |
---|
32 | * A registry that tracks each meta box instance. |
---|
33 | */ |
---|
34 | public static $registry; |
---|
35 | |
---|
36 | /** |
---|
37 | * All registered meta |
---|
38 | */ |
---|
39 | public $registered_meta; |
---|
40 | |
---|
41 | |
---|
42 | /** |
---|
43 | * Constructor. |
---|
44 | * |
---|
45 | * Any subclasses MUST call parent::_construct( $screen, $args ). |
---|
46 | * |
---|
47 | * @param string $screen - The ID (string) for the screen where the meta box will be shown. |
---|
48 | * @param array $args - An array of supplied arguments. Optional. |
---|
49 | * |
---|
50 | * $args recognized by default: |
---|
51 | * title - The title of the meta box. |
---|
52 | * context - The context within the page where the box should show ('normal', 'advanced'). |
---|
53 | * priority - The priority within the context where the boxes should show ('high', 'low'). |
---|
54 | * slug - A unique string to identify the meta box. |
---|
55 | */ |
---|
56 | public function __construct( $screen, $args = array() ) { |
---|
57 | // Set variables |
---|
58 | $this->screen = $screen; |
---|
59 | $this->slug = empty( $args['slug'] ) ? '' : $args['slug']; |
---|
60 | |
---|
61 | // Remove slug from args |
---|
62 | unset( $args['slug'] ); |
---|
63 | |
---|
64 | // Set default args |
---|
65 | $defaults = array( |
---|
66 | 'title' => __( 'Untitled' , 'wordcampbase'), |
---|
67 | 'context' => 'side', |
---|
68 | 'priority' => 'default', |
---|
69 | ); |
---|
70 | $this->args = wp_parse_args( $args, $defaults ); |
---|
71 | |
---|
72 | // Add the meta box to the registry. |
---|
73 | // Generates a slug if one doesn't already exist. |
---|
74 | WP_Meta_Box::registry()->add( $this ); |
---|
75 | |
---|
76 | // Construct the meta box's unique ID. |
---|
77 | $this->unique_id = get_class( $this ) . "_{$this->screen}_{$this->slug}"; |
---|
78 | |
---|
79 | // Bind hooks |
---|
80 | add_action( 'admin_init', array( $this, '_register' ) ); |
---|
81 | add_action( 'admin_enqueue_scripts', array( $this, '_enqueue_scripts' ) ); |
---|
82 | } |
---|
83 | |
---|
84 | /** |
---|
85 | * Fetches the meta box registry. |
---|
86 | */ |
---|
87 | public static function registry() { |
---|
88 | if ( ! isset( WP_Meta_Box::$registry ) ) |
---|
89 | WP_Meta_Box::$registry = new WP_Meta_Box_Registry(); |
---|
90 | return WP_Meta_Box::$registry; |
---|
91 | } |
---|
92 | |
---|
93 | /** |
---|
94 | * Remove the meta box. |
---|
95 | */ |
---|
96 | public function remove() { |
---|
97 | // Make sure we've removed any data from the registry. |
---|
98 | WP_Meta_Box::registry()->remove( get_class( $this ), $this->screen, $this->slug ); |
---|
99 | |
---|
100 | // Unbind actions. |
---|
101 | remove_action( 'admin_init', array( $this, '_register' ) ); |
---|
102 | remove_action( 'admin_enqueue_scripts', array( $this, '_enqueue_scripts' ) ); |
---|
103 | } |
---|
104 | |
---|
105 | /** |
---|
106 | * Render the meta box. Implement in a subclass. |
---|
107 | */ |
---|
108 | protected function render() {} |
---|
109 | |
---|
110 | /** |
---|
111 | * Save the meta box. Implement in a subclass. |
---|
112 | */ |
---|
113 | protected function save() {} |
---|
114 | |
---|
115 | /** |
---|
116 | * Fires when the meta box is registered. Override in a subclass. |
---|
117 | */ |
---|
118 | protected function register() {} |
---|
119 | |
---|
120 | /** |
---|
121 | * Enqueue meta box scripts. Override in a subclass. |
---|
122 | */ |
---|
123 | protected function enqueue_scripts() {} |
---|
124 | |
---|
125 | /** |
---|
126 | * Determine whether the meta box will be saved. Override in a subclass. |
---|
127 | * |
---|
128 | * Return true to save, false to cancel. |
---|
129 | */ |
---|
130 | protected function maybe_save( $post_id, $post ) { |
---|
131 | // Bail if we're autosaving |
---|
132 | if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) |
---|
133 | return; |
---|
134 | |
---|
135 | // @TODO Add revision check |
---|
136 | |
---|
137 | // Cap check |
---|
138 | if ( ! current_user_can( 'edit_post', $post_id ) ) |
---|
139 | return; |
---|
140 | |
---|
141 | return true; |
---|
142 | } |
---|
143 | |
---|
144 | /** |
---|
145 | * Add an action to trigger save. |
---|
146 | * |
---|
147 | * Due to the different types of meta boxes, save will not be triggered by default. |
---|
148 | */ |
---|
149 | public function add_save_action( $name, $priority = 10 ) { |
---|
150 | add_action( $name, array( $this, '_save' ), $priority, 99 ); // Effectively infinite args. |
---|
151 | } |
---|
152 | |
---|
153 | /** |
---|
154 | * Remove a save action. |
---|
155 | */ |
---|
156 | public function remove_save_action( $name, $priority = 10 ) { |
---|
157 | remove_action( $name, array( $this, '_save' ), $priority, 99 ); // Effectively infinite args. |
---|
158 | } |
---|
159 | |
---|
160 | public function register_meta( $meta_key, $args_array = array() ) { |
---|
161 | $defaults = array( 'field_type' => 'text', 'default_display' => true, 'title_label' => $meta_key, 'attrs' => array() ); |
---|
162 | |
---|
163 | $args_array = wp_parse_args($args_array, $defaults); |
---|
164 | |
---|
165 | // export array as variables |
---|
166 | extract($args_array); |
---|
167 | // var_dump($title_label); |
---|
168 | $this->registered_meta[] = array( 'meta_key' => $meta_key, 'default_display' => $default_display, 'title_label' => $title_label, 'field_type' => $field_type, 'attrs' => $attrs ); |
---|
169 | } |
---|
170 | |
---|
171 | /* ===================================================================== |
---|
172 | * INTERNAL FUNCTIONS |
---|
173 | * ===================================================================== */ |
---|
174 | |
---|
175 | /** |
---|
176 | * Internal function. Registers the meta box. |
---|
177 | */ |
---|
178 | public final function _register() { |
---|
179 | $id = "{$this->unique_id}-meta-box"; |
---|
180 | |
---|
181 | add_meta_box( $id, $this->args['title'], array( $this, '_render' ), |
---|
182 | $this->screen, $this->args['context'], $this->args['priority'], |
---|
183 | $this->args ); |
---|
184 | |
---|
185 | $this->register(); |
---|
186 | } |
---|
187 | |
---|
188 | /** |
---|
189 | * Internal function. Ensures scripts are only loaded when necessary. |
---|
190 | */ |
---|
191 | public final function _enqueue_scripts() { |
---|
192 | $current_screen = get_current_screen(); |
---|
193 | |
---|
194 | if ( isset( $current_screen ) && $this->screen == $current_screen->id ) |
---|
195 | $this->enqueue_scripts(); |
---|
196 | } |
---|
197 | |
---|
198 | /** |
---|
199 | * Internal function, initiates the rendering process. |
---|
200 | */ |
---|
201 | public final function _render( $object, $box ) { |
---|
202 | wp_nonce_field( "{$this->unique_id}_nonce", "_wpnonce_{$this->unique_id}", false ); |
---|
203 | |
---|
204 | // Render registered meta boxes with default_display set to true |
---|
205 | foreach ( $this->registered_meta as $meta ) |
---|
206 | if ( $meta['default_display'] ) |
---|
207 | $this->_render_form_field( $meta ); |
---|
208 | |
---|
209 | $this->render(); |
---|
210 | } |
---|
211 | |
---|
212 | /** |
---|
213 | * Internal function, initiates the saving process. |
---|
214 | */ |
---|
215 | public final function _save() { |
---|
216 | global $post; |
---|
217 | // Nonce check (sorry, you don't have a choice about this one). |
---|
218 | check_admin_referer( "{$this->unique_id}_nonce", "_wpnonce_{$this->unique_id}" ); |
---|
219 | |
---|
220 | $args = func_get_args(); |
---|
221 | |
---|
222 | // Only save if maybe_save returns true. |
---|
223 | if ( call_user_func_array( array( $this, 'maybe_save' ), $args ) ) { |
---|
224 | |
---|
225 | // Save registered meta boxes |
---|
226 | foreach ( $this->registered_meta as $meta ) |
---|
227 | if ( $_REQUEST[$meta['meta_key']] ) |
---|
228 | update_post_meta( $post->ID, $meta['meta_key'], $_REQUEST[$meta['meta_key']] ); |
---|
229 | |
---|
230 | call_user_func_array( array( $this, 'save' ), $args ); |
---|
231 | } |
---|
232 | |
---|
233 | } |
---|
234 | |
---|
235 | public function _render_form_field( $args ) { |
---|
236 | global $post; |
---|
237 | extract($args); |
---|
238 | $value = get_post_meta($post->ID, $meta_key, true ); |
---|
239 | |
---|
240 | echo "<h4>$title_label</h4>"; |
---|
241 | switch( $field_type ) { |
---|
242 | case 'text' : |
---|
243 | $value = get_post_meta($post->ID, $meta_key, true); |
---|
244 | echo "<input type='text' name='$meta_key' value='$value'>"; |
---|
245 | break; |
---|
246 | } |
---|
247 | } |
---|
248 | |
---|
249 | } |
---|
250 | |
---|
251 | |
---|
252 | |
---|
253 | /** |
---|
254 | * Meta Box Registry |
---|
255 | * |
---|
256 | * Implemented as singleton |
---|
257 | * |
---|
258 | */ |
---|
259 | class WP_Meta_Box_Registry { |
---|
260 | |
---|
261 | /** |
---|
262 | * WP_Meta_Box_Registry singleton implementation |
---|
263 | * |
---|
264 | * @var WP_Meta_Box_Registry |
---|
265 | */ |
---|
266 | private static $instance; |
---|
267 | |
---|
268 | private $instances = array(); |
---|
269 | |
---|
270 | /** |
---|
271 | * WP_Meta_Box_Registry singleton implementation |
---|
272 | * |
---|
273 | * @return WP_Meta_Box_Registry |
---|
274 | */ |
---|
275 | public static function instance() { |
---|
276 | if (null === self::$instance) |
---|
277 | self::$instance = new self(); |
---|
278 | return self::$instance; |
---|
279 | } |
---|
280 | |
---|
281 | /** |
---|
282 | * Search registry for meta box instances |
---|
283 | * |
---|
284 | * @return array result |
---|
285 | */ |
---|
286 | public function search($class_or_object, $screen = false, $slug = false) { |
---|
287 | $instances = array(); |
---|
288 | |
---|
289 | foreach($this->instances as $instance) { |
---|
290 | |
---|
291 | if ( ! $instance instanceof $class_or_object ) |
---|
292 | continue; |
---|
293 | |
---|
294 | if ( $screen !== false && $instance->screen !== $screen ) |
---|
295 | continue; |
---|
296 | |
---|
297 | if ( $slug !== false && $instance->slug !== $slug ) |
---|
298 | continue; |
---|
299 | |
---|
300 | $instances[] = $instance; |
---|
301 | } |
---|
302 | |
---|
303 | return $instances; |
---|
304 | } |
---|
305 | |
---|
306 | /** |
---|
307 | * Adds a meta box instance. |
---|
308 | * |
---|
309 | * If $instance->slug is defined, will use $slug. |
---|
310 | * If a meta box with the same slug exists, it will be overwritten. |
---|
311 | * |
---|
312 | * @param WP_Meta_Box $instance |
---|
313 | */ |
---|
314 | public function add( WP_Meta_Box $instance ) { |
---|
315 | static $counter = 0; |
---|
316 | |
---|
317 | $hash = spl_object_hash( $instance ); |
---|
318 | |
---|
319 | if ( !empty( $instance->slug ) ) { |
---|
320 | // If slug is specified, remove existing instance |
---|
321 | $instances = $this->find($instance, $instance->screen, $instance->slug); |
---|
322 | |
---|
323 | if ($instances) |
---|
324 | $this->remove($instances[0]); |
---|
325 | |
---|
326 | } else { |
---|
327 | // If no slug is specified, get the numerical index. |
---|
328 | // alternatively get the number of this instances' class by screen and count plus one. |
---|
329 | $instance->slug = ++$counter; |
---|
330 | } |
---|
331 | |
---|
332 | $this->instances[ $hash ] = $instance; |
---|
333 | } |
---|
334 | |
---|
335 | // in case this is still needed. |
---|
336 | public function get( WP_Meta_Box $instance ) { |
---|
337 | $hash = spl_object_hash( $instance ); |
---|
338 | |
---|
339 | if ( isset( $this->instances[ $hash ] ) ) |
---|
340 | return $instance; |
---|
341 | |
---|
342 | return false; |
---|
343 | } |
---|
344 | |
---|
345 | /** |
---|
346 | * Remove instance from registry |
---|
347 | * |
---|
348 | * @param WP_Meta_Box $instance |
---|
349 | */ |
---|
350 | public function remove( WP_Meta_Box $instance ) { |
---|
351 | $hash = spl_object_hash( $instance ); |
---|
352 | |
---|
353 | if ( isset( $this->instances[ $hash ] ) ) |
---|
354 | unset( $this->instances[ $hash ] ); |
---|
355 | } |
---|
356 | } |
---|
357 | |
---|
358 | class WP_Basic_Meta_Box extends WP_Meta_Box { |
---|
359 | function __construct( $screen, $args = array() ) { |
---|
360 | // Call the WP_Meta_Box constructor. |
---|
361 | parent::__construct( $screen, $args ); |
---|
362 | |
---|
363 | // Save the meta box contents when 'save_post' is triggered. |
---|
364 | $this->add_save_action( 'save_post' ); |
---|
365 | $this->register_meta( 'test_form_field' ); |
---|
366 | } |
---|
367 | } |
---|
368 | |
---|
369 | $a = new WP_Basic_Meta_Box( 'post', array( 'title' => 'Basic Meta Box' ) ); |
---|
370 | |
---|
371 | class WP_Basic_Meta_Box_with_Custom_Render extends WP_Meta_Box { |
---|
372 | function __construct( $screen, $args = array() ) { |
---|
373 | // Call the WP_Meta_Box constructor. |
---|
374 | parent::__construct( $screen, $args ); |
---|
375 | |
---|
376 | // Save the meta box contents when 'save_post' is triggered. |
---|
377 | $this->add_save_action( 'save_post' ); |
---|
378 | $this->register_meta( 'test_form_field', array( 'default_display' => false, 'title_label' => 'test' ) ); |
---|
379 | } |
---|
380 | |
---|
381 | function render() { |
---|
382 | echo 'custom meta box form rendering here'; |
---|
383 | } |
---|
384 | } |
---|
385 | |
---|
386 | $b = new WP_Basic_Meta_Box_with_Custom_Render( 'post', array( 'title' => 'Basic Meta Box with Custom Form rendering' ) ); |
---|