register_setting( string $option_group, string $option_name, array $args = array() )

Registers a setting and its data.

Parameters

$option_groupstringrequired
A settings group name. Should correspond to an allowed option key name.
Default allowed option key names include 'general', 'discussion', 'media', 'reading', 'writing', and 'options'.
$option_namestringrequired
The name of an option to sanitize and save.
$argsarrayoptional
Data used to describe the setting when registered.
  • type string
    The type of data associated with this setting.
    Valid values are 'string', 'boolean', 'integer', 'number', 'array', and 'object'.
  • description string
    A description of the data attached to this setting.
  • sanitize_callback callable
    A callback function that sanitizes the option’s value.
  • show_in_rest bool|array
    Whether data associated with this setting should be included in the REST API.
    When registering complex settings, this argument may optionally be an array with a 'schema' key.
  • default mixed
    Default value when calling get_option().

Default:array()

Source

function register_setting( $option_group, $option_name, $args = array() ) {
	global $new_allowed_options, $wp_registered_settings;

	/*
	 * In 5.5.0, the `$new_whitelist_options` global variable was renamed to `$new_allowed_options`.
	 * Please consider writing more inclusive code.
	 */
	$GLOBALS['new_whitelist_options'] = &$new_allowed_options;

	$defaults = array(
		'type'              => 'string',
		'group'             => $option_group,
		'description'       => '',
		'sanitize_callback' => null,
		'show_in_rest'      => false,
	);

	// Back-compat: old sanitize callback is added.
	if ( is_callable( $args ) ) {
		$args = array(
			'sanitize_callback' => $args,
		);
	}

	/**
	 * Filters the registration arguments when registering a setting.
	 *
	 * @since 4.7.0
	 *
	 * @param array  $args         Array of setting registration arguments.
	 * @param array  $defaults     Array of default arguments.
	 * @param string $option_group Setting group.
	 * @param string $option_name  Setting name.
	 */
	$args = apply_filters( 'register_setting_args', $args, $defaults, $option_group, $option_name );

	$args = wp_parse_args( $args, $defaults );

	// Require an item schema when registering settings with an array type.
	if ( false !== $args['show_in_rest'] && 'array' === $args['type'] && ( ! is_array( $args['show_in_rest'] ) || ! isset( $args['show_in_rest']['schema']['items'] ) ) ) {
		_doing_it_wrong( __FUNCTION__, __( 'When registering an "array" setting to show in the REST API, you must specify the schema for each array item in "show_in_rest.schema.items".' ), '5.4.0' );
	}

	if ( ! is_array( $wp_registered_settings ) ) {
		$wp_registered_settings = array();
	}

	if ( 'misc' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.0.0',
			sprintf(
				/* translators: %s: misc */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'misc'
			)
		);
		$option_group = 'general';
	}

	if ( 'privacy' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.5.0',
			sprintf(
				/* translators: %s: privacy */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'privacy'
			)
		);
		$option_group = 'reading';
	}

	$new_allowed_options[ $option_group ][] = $option_name;

	if ( ! empty( $args['sanitize_callback'] ) ) {
		add_filter( "sanitize_option_{$option_name}", $args['sanitize_callback'] );
	}
	if ( array_key_exists( 'default', $args ) ) {
		add_filter( "default_option_{$option_name}", 'filter_default_option', 10, 3 );
	}

	/**
	 * Fires immediately before the setting is registered but after its filters are in place.
	 *
	 * @since 5.5.0
	 *
	 * @param string $option_group Setting group.
	 * @param string $option_name  Setting name.
	 * @param array  $args         Array of setting registration arguments.
	 */
	do_action( 'register_setting', $option_group, $option_name, $args );

	$wp_registered_settings[ $option_name ] = $args;
}

Hooks

do_action( ‘register_setting’, string $option_group, string $option_name, array $args )

Fires immediately before the setting is registered but after its filters are in place.

apply_filters( ‘register_setting_args’, array $args, array $defaults, string $option_group, string $option_name )

Filters the registration arguments when registering a setting.

Changelog

VersionDescription
5.5.0$new_whitelist_options was renamed to $new_allowed_options.
Please consider writing more inclusive code.
4.7.0$args can be passed to set flags on the setting, similar to register_meta().
3.5.0The privacy option group was deprecated.
3.0.0The misc option group was deprecated.
2.7.0Introduced.

User Contributed Notes

  1. Skip to note 11 content

    Some notes about the elements in the $args parameter:

    'type':

    • Only has an effect if 'show_in_rest' is set. So if 'show_in_rest' is false or not part of $args, do not bother with setting a 'type'.
    • Only used by the REST API to define the schema associated with the setting and to implement sanitization over the REST API.
    • Has no effect for the workings of the Admin pages or the way the Setting is handled by the Options API. (I.e.: although probably you shouldn’t, it is possible to submit for example a string value for a setting from the Admin forms that has the 'type' set to "boolean". WP will not complain and will store the value in the options table. It would however cause issues with the REST API, so be careful!)
    • On top of those listed in this page, it also accepts values such as: 'array' and 'object'.

    'description':

    • Only has an effect if 'show_in_rest' is set. So if 'show_in_rest' is false or not part of $args, do not bother with setting a 'description'.
    • Only used by the REST API.

    'default':

    • Affects both the Options API (e.g. get_option()) and the REST API.

    In conclusion: if you do not plan to include your setting in the REST API, it is perfectly enough to only set the 'default' and the 'sanitize_callback' elements in the $args array. Anything else would be ignored anyway.

  2. Skip to note 12 content
    /**
    * Registers a text field setting for WordPress 4.7 and higher.
    **/
    function register_my_setting() {
    	$args = array(
    			'type' => 'string', 
    			'sanitize_callback' => 'sanitize_text_field',
    			'default' => NULL,
    			);
        register_setting( 'my_options_group', 'my_option_name', $args ); 
    } 
    add_action( 'admin_init', 'register_my_setting' );
  3. Skip to note 15 content

    The sanitize callback will be launched twice! Therefore, if sanitizing involves any performance critical or singular tasks, then measures must be taken in the callback to avoid duplicate execution of those portions.

    const	PLUGIN_SLUG =	'MyPlugin';
    
    /*
     *	Setup Plug-In Hooks (Namespaced Example)
     */
    \add_action( 'wp_loaded', __NAMESPACE__.'\on_wp_loaded' );
    
    if ( is_blog_admin() ) {
    	\register_activation_hook( __FILE__,  __NAMESPACE__.'\on_activate' );
    	\register_deactivation_hook( __FILE__,  __NAMESPACE__.'\on_deactivate' );
    	
    	\add_action( 'admin_menu', __NAMESPACE__.'\on_admin_menu' );
    	\add_action( 'admin_init', __NAMESPACE__.'\on_admin_init' );
    	\add_filter( 'plugin_action_links_' . plugin_basename( __FILE__ ), __NAMESPACE__.'\action_links' );
    }
    return;
    
    /*
     *	Add custom options to whitelist, allowing valiated settings to be saved by form.
     */
    function on_admin_init(): void 
    {
    	\register_setting( PLUGIN_SLUG, PLUGIN_SLUG, [ 'sanitize_callback' => __NAMESPACE__.'\sanitize_settings' ] ); 
    }
    
    /*
     *	Sanitize the form input.
     */
    function sanitize_settings( $input = NULL ):  
    {
    	// Detect multiple sanitizing passes.
    	// Accomodates bug: https://core.trac.wordpress.org/ticket/21989
    	static $pass_count = 0; $pass_count++;
    
    	if ( $pass_count <= 1 ) {
    		// Handle any single-time / performane sensitive actions.
    
    	}
    
    	// Insert regular santizing code here.
    }
  4. Skip to note 16 content

    If you want the setting to appear in the wp-json/wp/v2/settings endpoint, you’ll need to call register_setting() on the rest_api_init action, in addition to the normal admin_init action.

    add_action( 'admin_init',    'foo_register_settings' );
    add_action( 'rest_api_init', 'foo_register_settings' );
    
    function foo_register_settings() {
    	register_setting(
    		'foo',
    		'foo_my_setting',
    		array(
    			'type'              => 'string',
    			'show_in_rest'      => true,
    			'sanitize_callback' => 'sanitize_text_field',
    		)
    	);
    }
  5. Skip to note 17 content

    An example of array settings. if you want to save an array in settings and also show the array setting to appear in the wp-json/wp/v2/settings endpoint, then you have to register show_in_rest schema.

    add_action( 'admin_init',    'wpdocs_foo_register_settings' );
    add_action( 'rest_api_init', 'wpdocs_foo_register_settings' );
    function wpdocs_foo_register_settings() {
    	register_setting( 'general_setting', 'id' );
    	register_setting( 'general_setting', 'order' );
    	register_setting(
    		'general_setting',
    		'slider-data',
    		array(
    			'show_in_rest' => array(
    				'name' => 'images_slide',
    				'schema' => array(
    					'type'  => 'array',
    					'items' => array(
    						'id'    => 'string',
    						'order' => 'string',
    					),
    				),
    			),
    			'type' => 'array',
    			'sanitize_callback' => array( $this, 'wpdocs_admin_post_save_data' ),
    		)
    	);
    }
  6. Skip to note 18 content

    Example for object and array types:

    register_setting(
    	'dp_example_settings_group',
    	'dp_example_array_settings',
    	array(
    		'type'         => 'object',
    		'default'      => array(
    			'A',
    			'B',
    			'C',
    		),
    		'show_in_rest' => array(
    			'schema' => array(
    				'type'  => 'object',
    				'items' => array(
    					'type' => 'string',
    				),
    			),
    		),
    	)
    );
    
    register_setting(
    	'dp_example_settings_group',
    	'dp_example_object_settings',
    	array(
    		'type'         => 'object',
    		'default'      => array(
    			'some_str' => 'A',
    			'some_int' => 3,
    		),
    		'show_in_rest' => array(
    			'schema' => array(
    				'type'       => 'object',
    				'properties' => array(
    					'some_str' => array(
    						'type' => 'string',
    					),
    					'some_int' => array(
    						'type' => 'integer',
    					),
    				),
    			),
    		),
    	)
    );
  7. Skip to note 19 content
    // Registering the field
    function wpdocs_add_option_field_to_general_admin_page() {
    
    	register_setting( 'general', 'Field_Name_To_Add' );
    
    	add_settings_field( 
    		'field_id-to-add', 
    		'Field Name To Display', 
    		'wpdocs_setting_callback_function', //Function to Call
    		'general', 
    		'default', 
    		array( 
    			'id' => 'field_id-to-add', 
    			'option_name' => 'Field_Name_To_Add' 
    		)
    	);
    }
    
    // Adding options to registered field
    add_action( 'admin_menu', 'wpdocs_add_option_field_to_general_admin_page' ); // CallBack Function
    
    function wpdocs_setting_callback_function( $val ) {
    	$id = $val['id'];
    	$option_name = $val['option_name'];
    	?>
    	<input 
    		type="tel" //this can be any HTML input type: date, number, text etc.
    		name="<?php echo esc_attr( $option_name ) ?>"
    		id="<?php echo esc_attr( $id ) ?>" 
    		value="<?php echo esc_attr( get_option( $option_name ) ) ?>" // Displays the value stored in DB
    	/> 
    	<?php
    }
  8. Skip to note 20 content

    Notice that the sanitization_callback of all the registered settings that share the same $option_group will be executed when saving that option group.

    This sounds obvious, but notice that it will also happen even when the settings that belong to this group are not present in the current page but in a different one.

    For example if we have the following option pages and settings:

    admin.php?page=settings_page_1 containing the optionA form
    admin.php?page=settings_page_2 containing the optionB form

    Where each setting has been registered with their own register_setting() in different files and being output in different pages but the same $option_group string has been used for both of them.

    Saving the page admin.php?page=settings_page_1 will not only trigger the sanitization_callback from optionA, but also the sanitization_callback from optionB.

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