5 * Field API documentation.
14 * @defgroup field_types Field Types API
16 * Defines field, widget, display formatter, and storage types.
18 * In the Field API, each field has a type, which determines what kind of data
19 * (integer, string, date, etc.) the field can hold, which settings it provides,
20 * and so on. The data type(s) accepted by a field are defined in
21 * hook_field_schema().
23 * Field types are plugins annotated with class
24 * \Drupal\Core\Field\Annotation\FieldType, and implement plugin interface
25 * \Drupal\Core\Field\FieldItemInterface. Field Type plugins are managed by the
26 * \Drupal\Core\Field\FieldTypePluginManager class. Field type classes usually
27 * extend base class \Drupal\Core\Field\FieldItemBase. Field-type plugins need
28 * to be in the namespace \Drupal\{your_module}\Plugin\Field\FieldType. See the
29 * @link plugin_api Plugin API topic @endlink for more information on how to
32 * The Field Types API also defines two kinds of pluggable handlers: widgets
33 * and formatters. @link field_widget Widgets @endlink specify how the field
34 * appears in edit forms, while @link field_formatter formatters @endlink
35 * specify how the field appears in displayed entities.
37 * See @link field Field API @endlink for information about the other parts of
42 * @see field_formatter
48 * Perform alterations on Field API field types.
51 * Array of information on field types as collected by the "field type" plugin
54 function hook_field_info_alter(&$info) {
55 // Change the default widget for fields of type 'foo'.
56 if (isset($info['foo'])) {
57 $info['foo']['default widget'] = 'mymodule_widget';
62 * Perform alterations on preconfigured field options.
64 * @param array $options
65 * Array of options as returned from
66 * \Drupal\Core\Field\PreconfiguredFieldUiOptionsInterface::getPreconfiguredOptions().
67 * @param string $field_type
68 * The field type plugin ID.
70 * @see \Drupal\Core\Field\PreconfiguredFieldUiOptionsInterface::getPreconfiguredOptions()
72 function hook_field_ui_preconfigured_options_alter(array &$options, $field_type) {
73 // If the field is not an "entity_reference"-based field, bail out.
74 /** @var \Drupal\Core\Field\FieldTypePluginManager $field_type_manager */
75 $field_type_manager = \Drupal::service('plugin.manager.field.field_type');
76 $class = $field_type_manager->getPluginClass($field_type);
77 if (!is_a($class, 'Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem', TRUE)) {
81 // Set the default formatter for media in entity reference fields to be the
82 // "Rendered entity" formatter.
83 if (!empty($options['media'])) {
84 $options['media']['entity_view_display']['type'] = 'entity_reference_entity_view';
89 * Forbid a field storage update from occurring.
91 * Any module may forbid any update for any reason. For example, the
92 * field's storage module might forbid an update if it would change
93 * the storage schema while data for the field exists. A field type
94 * module might forbid an update if it would change existing data's
95 * semantics, or if there are external dependencies on field settings
96 * that cannot be updated.
98 * To forbid the update from occurring, throw a
99 * \Drupal\Core\Entity\Exception\FieldStorageDefinitionUpdateForbiddenException.
101 * @param \Drupal\field\FieldStorageConfigInterface $field_storage
102 * The field storage as it will be post-update.
103 * @param \Drupal\field\FieldStorageConfigInterface $prior_field_storage
104 * The field storage as it is pre-update.
108 function hook_field_storage_config_update_forbid(\Drupal\field\FieldStorageConfigInterface $field_storage, \Drupal\field\FieldStorageConfigInterface $prior_field_storage) {
109 if ($field_storage->module == 'options' && $field_storage->hasData()) {
110 // Forbid any update that removes allowed values with actual data.
111 $allowed_values = $field_storage->getSetting('allowed_values');
112 $prior_allowed_values = $prior_field_storage->getSetting('allowed_values');
113 $lost_keys = array_keys(array_diff_key($prior_allowed_values, $allowed_values));
114 if (_options_values_in_use($field_storage->getTargetEntityTypeId(), $field_storage->getName(), $lost_keys)) {
115 throw new \Drupal\Core\Entity\Exception\FieldStorageDefinitionUpdateForbiddenException(t('A list field (@field_name) with existing data cannot have its keys changed.', ['@field_name' => $field_storage->getName()]));
121 * @} End of "defgroup field_types".
125 * @defgroup field_widget Field Widget API
127 * Define Field API widget types.
129 * Field API widgets specify how fields are displayed in edit forms. Fields of a
130 * given @link field_types field type @endlink may be edited using more than one
131 * widget. In this case, the Field UI module allows the site builder to choose
132 * which widget to use.
134 * Widgets are Plugins managed by the
135 * \Drupal\Core\Field\WidgetPluginManager class. A widget is a plugin annotated
136 * with class \Drupal\Core\Field\Annotation\FieldWidget that implements
137 * \Drupal\Core\Field\WidgetInterface (in most cases, by
138 * subclassing \Drupal\Core\Field\WidgetBase). Widget plugins need to be in the
139 * namespace \Drupal\{your_module}\Plugin\Field\FieldWidget.
141 * Widgets are @link form_api Form API @endlink elements with additional
142 * processing capabilities. The methods of the WidgetInterface object are
143 * typically called by respective methods in the
144 * \Drupal\Core\Entity\Entity\EntityFormDisplay class.
148 * @see field_formatter
153 * Perform alterations on Field API widget types.
156 * An array of information on existing widget types, as collected by the
157 * annotation discovery mechanism.
159 function hook_field_widget_info_alter(array &$info) {
160 // Let a new field type re-use an existing widget.
161 $info['options_select']['field_types'][] = 'my_field_type';
165 * Alter forms for field widgets provided by other modules.
167 * This hook can only modify individual elements within a field widget and
168 * cannot alter the top level (parent element) for multi-value fields. In most
169 * cases, you should use hook_field_widget_multivalue_form_alter() instead and
170 * loop over the elements.
173 * The field widget form element as constructed by
174 * \Drupal\Core\Field\WidgetBaseInterface::form().
176 * The current state of the form.
178 * An associative array containing the following key-value pairs:
179 * - form: The form structure to which widgets are being attached. This may be
180 * a full form structure, or a sub-element of a larger form.
181 * - widget: The widget plugin instance.
182 * - items: The field values, as a
183 * \Drupal\Core\Field\FieldItemListInterface object.
184 * - delta: The order of this item in the array of subelements (0, 1, 2, etc).
185 * - default: A boolean indicating whether the form is being shown as a dummy
186 * form to set default values.
188 * @see \Drupal\Core\Field\WidgetBaseInterface::form()
189 * @see \Drupal\Core\Field\WidgetBase::formSingleElement()
190 * @see hook_field_widget_WIDGET_TYPE_form_alter()
191 * @see hook_field_widget_multivalue_form_alter()
193 function hook_field_widget_form_alter(&$element, \Drupal\Core\Form\FormStateInterface $form_state, $context) {
194 // Add a css class to widget form elements for all fields of type mytype.
195 $field_definition = $context['items']->getFieldDefinition();
196 if ($field_definition->getType() == 'mytype') {
197 // Be sure not to overwrite existing attributes.
198 $element['#attributes']['class'][] = 'myclass';
203 * Alter widget forms for a specific widget provided by another module.
205 * Modules can implement hook_field_widget_WIDGET_TYPE_form_alter() to modify a
206 * specific widget form, rather than using hook_field_widget_form_alter() and
207 * checking the widget type.
209 * This hook can only modify individual elements within a field widget and
210 * cannot alter the top level (parent element) for multi-value fields. In most
211 * cases, you should use hook_field_widget_multivalue_WIDGET_TYPE_form_alter()
212 * instead and loop over the elements.
215 * The field widget form element as constructed by
216 * \Drupal\Core\Field\WidgetBaseInterface::form().
218 * The current state of the form.
220 * An associative array. See hook_field_widget_form_alter() for the structure
221 * and content of the array.
223 * @see \Drupal\Core\Field\WidgetBaseInterface::form()
224 * @see \Drupal\Core\Field\WidgetBase::formSingleElement()
225 * @see hook_field_widget_form_alter()
226 * @see hook_field_widget_multivalue_WIDGET_TYPE_form_alter()
228 function hook_field_widget_WIDGET_TYPE_form_alter(&$element, \Drupal\Core\Form\FormStateInterface $form_state, $context) {
229 // Code here will only act on widgets of type WIDGET_TYPE. For example,
230 // hook_field_widget_mymodule_autocomplete_form_alter() will only act on
231 // widgets of type 'mymodule_autocomplete'.
232 $element['#autocomplete_route_name'] = 'mymodule.autocomplete_route';
236 * Alter forms for multi-value field widgets provided by other modules.
238 * To alter the individual elements within the widget, loop over
239 * \Drupal\Core\Render\Element::children($elements).
241 * @param array $elements
242 * The field widget form elements as constructed by
243 * \Drupal\Core\Field\WidgetBase::formMultipleElements().
244 * @param \Drupal\Core\Form\FormStateInterface $form_state
245 * The current state of the form.
246 * @param array $context
247 * An associative array containing the following key-value pairs:
248 * - form: The form structure to which widgets are being attached. This may be
249 * a full form structure, or a sub-element of a larger form.
250 * - widget: The widget plugin instance.
251 * - items: The field values, as a
252 * \Drupal\Core\Field\FieldItemListInterface object.
253 * - default: A boolean indicating whether the form is being shown as a dummy
254 * form to set default values.
256 * @see \Drupal\Core\Field\WidgetBaseInterface::form()
257 * @see \Drupal\Core\Field\WidgetBase::formMultipleElements()
258 * @see hook_field_widget_multivalue_WIDGET_TYPE_form_alter()
260 function hook_field_widget_multivalue_form_alter(array &$elements, \Drupal\Core\Form\FormStateInterface $form_state, array $context) {
261 // Add a css class to widget form elements for all fields of type mytype.
262 $field_definition = $context['items']->getFieldDefinition();
263 if ($field_definition->getType() == 'mytype') {
264 // Be sure not to overwrite existing attributes.
265 $elements['#attributes']['class'][] = 'myclass';
270 * Alter multi-value widget forms for a widget provided by another module.
272 * Modules can implement hook_field_widget_multivalue_WIDGET_TYPE_form_alter() to
273 * modify a specific widget form, rather than using
274 * hook_field_widget_form_alter() and checking the widget type.
276 * To alter the individual elements within the widget, loop over
277 * \Drupal\Core\Render\Element::children($elements).
279 * @param array $elements
280 * The field widget form elements as constructed by
281 * \Drupal\Core\Field\WidgetBase::formMultipleElements().
282 * @param \Drupal\Core\Form\FormStateInterface $form_state
283 * The current state of the form.
284 * @param array $context
285 * An associative array. See hook_field_widget_multivalue_form_alter() for
286 * the structure and content of the array.
288 * @see \Drupal\Core\Field\WidgetBaseInterface::form()
289 * @see \Drupal\Core\Field\WidgetBase::formMultipleElements()
290 * @see hook_field_widget_multivalue_form_alter()
292 function hook_field_widget_multivalue_WIDGET_TYPE_form_alter(array &$elements, \Drupal\Core\Form\FormStateInterface $form_state, array $context) {
293 // Code here will only act on widgets of type WIDGET_TYPE. For example,
294 // hook_field_widget_multivalue_mymodule_autocomplete_form_alter() will only
295 // act on widgets of type 'mymodule_autocomplete'.
296 // Change the autcomplete route for each autocomplete element within the
297 // multivalue widget.
298 foreach (Element::children($elements) as $delta => $element) {
299 $elements[$delta]['#autocomplete_route_name'] = 'mymodule.autocomplete_route';
304 * @} End of "defgroup field_widget".
309 * @defgroup field_formatter Field Formatter API
311 * Define Field API formatter types.
313 * Field API formatters specify how fields are displayed when the entity to
314 * which the field is attached is displayed. Fields of a given
315 * @link field_types field type @endlink may be displayed using more than one
316 * formatter. In this case, the Field UI module allows the site builder to
317 * choose which formatter to use.
319 * Formatters are Plugins managed by the
320 * \Drupal\Core\Field\FormatterPluginManager class. A formatter is a plugin
321 * annotated with class \Drupal\Core\Field\Annotation\FieldFormatter that
322 * implements \Drupal\Core\Field\FormatterInterface (in most cases, by
323 * subclassing \Drupal\Core\Field\FormatterBase). Formatter plugins need to be
324 * in the namespace \Drupal\{your_module}\Plugin\Field\FieldFormatter.
333 * Perform alterations on Field API formatter types.
336 * An array of information on existing formatter types, as collected by the
337 * annotation discovery mechanism.
339 function hook_field_formatter_info_alter(array &$info) {
340 // Let a new field type re-use an existing formatter.
341 $info['text_default']['field_types'][] = 'my_field_type';
345 * @} End of "defgroup field_formatter".
349 * Returns the maximum weight for the entity components handled by the module.
351 * Field API takes care of fields and 'extra_fields'. This hook is intended for
352 * third-party modules adding other entity components (e.g. field_group).
354 * @param string $entity_type
355 * The type of entity; e.g. 'node' or 'user'.
356 * @param string $bundle
358 * @param string $context
359 * The context for which the maximum weight is requested. Either 'form' or
361 * @param string $context_mode
362 * The view or form mode name.
365 * The maximum weight of the entity's components, or NULL if no components
368 * @ingroup field_info
370 function hook_field_info_max_weight($entity_type, $bundle, $context, $context_mode) {
373 foreach (my_module_entity_additions($entity_type, $bundle, $context, $context_mode) as $addition) {
374 $weights[] = $addition['weight'];
377 return $weights ? max($weights) : NULL;
381 * @addtogroup field_purge
386 * Acts when a field storage definition is being purged.
388 * In field_purge_field_storage(), after the storage definition has been removed
389 * from the system, the entity storage has purged stored field data, and the
390 * field definitions cache has been cleared, this hook is invoked on all modules
391 * to allow them to respond to the field storage being purged.
393 * @param $field_storage \Drupal\field\Entity\FieldStorageConfig
394 * The field storage being purged.
396 function hook_field_purge_field_storage(\Drupal\field\Entity\FieldStorageConfig $field_storage) {
397 db_delete('my_module_field_storage_info')
398 ->condition('uuid', $field_storage->uuid())
403 * Acts when a field is being purged.
405 * In field_purge_field(), after the field definition has been removed
406 * from the system, the entity storage has purged stored field data, and the
407 * field info cache has been cleared, this hook is invoked on all modules to
408 * allow them to respond to the field being purged.
411 * The field being purged.
413 function hook_field_purge_field(\Drupal\field\Entity\FieldConfig $field) {
414 db_delete('my_module_field_info')
415 ->condition('id', $field->id())
420 * @} End of "addtogroup field_purge".
424 * @} End of "addtogroup hooks".