<?php
/**
* Abilities API
*
* Defines WP_Ability class.
*
* @package WordPress
* @subpackage Abilities API
* @since 6.9.0
*/
declare( strict_types = 1 );
/**
* Encapsulates the properties and methods related to a specific ability in the registry.
*
* @since 6.9.0
*
* @see WP_Abilities_Registry
*/
class WP_Ability {
/**
* The default value for the `show_in_rest` meta.
*
* @since 6.9.0
* @var bool
*/
protected const DEFAULT_SHOW_IN_REST = false;
/**
* The default ability annotations.
* They are not guaranteed to provide a faithful description of ability behavior.
*
* @since 6.9.0
* @var array<string, bool|null>
*/
protected static $default_annotations = array(
// If true, the ability does not modify its environment.
'readonly' => null,
/*
* If true, the ability may perform destructive updates to its environment.
* If false, the ability performs only additive updates.
*/
'destructive' => null,
/*
* If true, calling the ability repeatedly with the same arguments will have no additional effect
* on its environment.
*/
'idempotent' => null,
);
/**
* The name of the ability, with its namespace.
* Example: `my-plugin/my-ability`.
*
* @since 6.9.0
* @var string
*/
protected $name;
/**
* The human-readable ability label.
*
* @since 6.9.0
* @var string
*/
protected $label;
/**
* The detailed ability description.
*
* @since 6.9.0
* @var string
*/
protected $description;
/**
* The ability category.
*
* @since 6.9.0
* @var string
*/
protected $category;
/**
* The optional ability input schema.
*
* @since 6.9.0
* @var array<string, mixed>
*/
protected $input_schema = array();
/**
* The optional ability output schema.
*
* @since 6.9.0
* @var array<string, mixed>
*/
protected $output_schema = array();
/**
* The ability execute callback.
*
* @since 6.9.0
* @var callable( mixed $input= ): (mixed|WP_Error)
*/
protected $execute_callback;
/**
* The optional ability permission callback.
*
* @since 6.9.0
* @var callable( mixed $input= ): (bool|WP_Error)
*/
protected $permission_callback;
/**
* The optional ability metadata.
*
* @since 6.9.0
* @var array<string, mixed>
*/
protected $meta;
/**
* Constructor.
*
* Do not use this constructor directly. Instead, use the `wp_register_ability()` function.
*
* @access private
*
* @since 6.9.0
*
* @see wp_register_ability()
*
* @param string $name The name of the ability, with its namespace.
* @param array<string, mixed> $args {
* An associative array of arguments for the ability.
*
* @type string $label The human-readable label for the ability.
* @type string $description A detailed description of what the ability does.
* @type string $category The ability category slug this ability belongs to.
* @type callable $execute_callback A callback function to execute when the ability is invoked.
* Receives optional mixed input and returns mixed result or WP_Error.
* @type callable $permission_callback A callback function to check permissions before execution.
* Receives optional mixed input and returns bool or WP_Error.
* @type array<string, mixed> $input_schema Optional. JSON Schema definition for the ability's input.
* @type array<string, mixed> $output_schema Optional. JSON Schema definition for the ability's output.
* @type array<string, mixed> $meta {
* Optional. Additional metadata for the ability.
*
* @type array<string, bool|null> $annotations {
* Optional. Semantic annotations describing the ability's behavioral characteristics.
* These annotations are hints for tooling and documentation.
*
* @type bool|null $readonly Optional. If true, the ability does not modify its environment.
* @type bool|null $destructive Optional. If true, the ability may perform destructive updates to its environment.
* If false, the ability performs only additive updates.
* @type bool|null $idempotent Optional. If true, calling the ability repeatedly with the same arguments
* will have no additional effect on its environment.
* }
* @type bool $show_in_rest Optional. Whether to expose this ability in the REST API. Default false.
* }
* }
*/
public function __construct( string $name, array $args ) {
$this->name = $name;
$properties = $this->prepare_properties( $args );
foreach ( $properties as $property_name => $property_value ) {
if ( ! property_exists( $this, $property_name ) ) {
_doing_it_wrong(
__METHOD__,
sprintf(
/* translators: %s: Property name. */
__( 'Property "%1$s" is not a valid property for ability "%2$s". Please check the %3$s class for allowed properties.' ),
'<code>' . esc_html( $property_name ) . '</code>',
'<code>' . esc_html( $this->name ) . '</code>',
'<code>' . __CLASS__ . '</code>'
),
'6.9.0'
);
continue;
}
$this->$property_name = $property_value;
}
}
/**
* Prepares and validates the properties used to instantiate the ability.
*
* Errors are thrown as exceptions instead of WP_Errors to allow for simpler handling and overloading. They are then
* caught and converted to a WP_Error when by WP_Abilities_Registry::register().
*
* @since 6.9.0
*
* @see WP_Abilities_Registry::register()
*
* @param array<string, mixed> $args {
* An associative array of arguments used to instantiate the ability class.
*
* @type string $label The human-readable label for the ability.
* @type string $description A detailed description of what the ability does.
* @type string $category The ability category slug this ability belongs to.
* @type callable $execute_callback A callback function to execute when the ability is invoked.
* Receives optional mixed input and returns mixed result or WP_Error.
* @type callable $permission_callback A callback function to check permissions before execution.
* Receives optional mixed input and returns bool or WP_Error.
* @type array<string, mixed> $input_schema Optional. JSON Schema definition for the ability's input. Required if ability accepts an input.
* @type array<string, mixed> $output_schema Optional. JSON Schema definition for the ability's output.
* @type array<string, mixed> $meta {
* Optional. Additional metadata for the ability.
*
* @type array<string, bool|null> $annotations {
* Optional. Semantic annotations describing the ability's behavioral characteristics.
* These annotations are hints for tooling and documentation.
*
* @type bool|null $readonly Optional. If true, the ability does not modify its environment.
* @type bool|null $destructive Optional. If true, the ability may perform destructive updates to its environment.
* If false, the ability performs only additive updates.
* @type bool|null $idempotent Optional. If true, calling the ability repeatedly with the same arguments
* will have no additional effect on its environment.
* }
* @type bool $show_in_rest Optional. Whether to expose this ability in the REST API. Default false.
* }
* }
* @return array<string, mixed> {
* An associative array of arguments with validated and prepared properties for the ability class.
*
* @type string $label The human-readable label for the ability.
* @type string $description A detailed description of what the ability does.
* @type string $category The ability category slug this ability belongs to.
* @type callable $execute_callback A callback function to execute when the ability is invoked.
* Receives optional mixed input and returns mixed result or WP_Error.
* @type callable $permission_callback A callback function to check permissions before execution.
* Receives optional mixed input and returns bool or WP_Error.
* @type array<string, mixed> $input_schema Optional. JSON Schema definition for the ability's input.
* @type array<string, mixed> $output_schema Optional. JSON Schema definition for the ability's output.
* @type array<string, mixed> $meta {
* Additional metadata for the ability.
*
* @type array<string, bool|null> $annotations {
* Semantic annotations describing the ability's behavioral characteristics.
* These annotations are hints for tooling and documentation.
*
* @type bool|null $readonly If true, the ability does not modify its environment.
* @type bool|null $destructive If true, the ability may perform destructive updates to its environment.
* If false, the ability performs only additive updates.
* @type bool|null $idempotent If true, calling the ability repeatedly with the same arguments
* will have no additional effect on its environment.
* }
* @type bool $show_in_rest Whether to expose this ability in the REST API. Default false.
* }
* }
* @throws InvalidArgumentException if an argument is invalid.
*/
protected function prepare_properties( array $args ): array {
// Required args must be present and of the correct type.
if ( empty( $args['label'] ) || ! is_string( $args['label'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties must contain a `label` string.' )
);
}
if ( empty( $args['description'] ) || ! is_string( $args['description'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties must contain a `description` string.' )
);
}
if ( empty( $args['category'] ) || ! is_string( $args['category'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties must contain a `category` string.' )
);
}
if ( empty( $args['execute_callback'] ) || ! is_callable( $args['execute_callback'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties must contain a valid `execute_callback` function.' )
);
}
if ( empty( $args['permission_callback'] ) || ! is_callable( $args['permission_callback'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties must provide a valid `permission_callback` function.' )
);
}
// Optional args only need to be of the correct type if they are present.
if ( isset( $args['input_schema'] ) && ! is_array( $args['input_schema'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties should provide a valid `input_schema` definition.' )
);
}
if ( isset( $args['output_schema'] ) && ! is_array( $args['output_schema'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties should provide a valid `output_schema` definition.' )
);
}
if ( isset( $args['meta'] ) && ! is_array( $args['meta'] ) ) {
throw new InvalidArgumentException(
__( 'The ability properties should provide a valid `meta` array.' )
);
}
if ( isset( $args['meta']['annotations'] ) && ! is_array( $args['meta']['annotations'] ) ) {
throw new InvalidArgumentException(
__( 'The ability meta should provide a valid `annotations` array.' )
);
}
if ( isset( $args['meta']['show_in_rest'] ) && ! is_bool( $args['meta']['show_in_rest'] ) ) {
throw new InvalidArgumentException(
__( 'The ability meta should provide a valid `show_in_rest` boolean.' )
);
}
// Set defaults for optional meta.
$args['meta'] = wp_parse_args(
$args['meta'] ?? array(),
array(
'annotations' => static::$default_annotations,
'show_in_rest' => self::DEFAULT_SHOW_IN_REST,
)
);
$args['meta']['annotations'] = wp_parse_args(
$args['meta']['annotations'],
static::$default_annotations
);
return $args;
}
/**
* Retrieves the name of the ability, with its namespace.
* Example: `my-plugin/my-ability`.
*
* @since 6.9.0
*
* @return string The ability name, with its namespace.
*/
public function get_name(): string {
return $this->name;
}
/**
* Retrieves the human-readable label for the ability.
*
* @since 6.9.0
*
* @return string The human-readable ability label.
*/
public function get_label(): string {
return $this->label;
}
/**
* Retrieves the detailed description for the ability.
*
* @since 6.9.0
*
* @return string The detailed description for the ability.
*/
public function get_description(): string {
return $this->description;
}
/**
* Retrieves the ability category for the ability.
*
* @since 6.9.0
*
* @return string The ability category for the ability.
*/
public function get_category(): string {
return $this->category;
}
/**
* Retrieves the input schema for the ability.
*
* @since 6.9.0
*
* @return array<string, mixed> The input schema for the ability.
*/
public function get_input_schema(): array {
return $this->input_schema;
}
/**
* Retrieves the output schema for the ability.
*
* @since 6.9.0
*
* @return array<string, mixed> The output schema for the ability.
*/
public function get_output_schema(): array {
return $this->output_schema;
}
/**
* Retrieves the metadata for the ability.
*
* @since 6.9.0
*
* @return array<string, mixed> The metadata for the ability.
*/
public function get_meta(): array {
return $this->meta;
}
/**
* Retrieves a specific metadata item for the ability.
*
* @since 6.9.0
*
* @param string $key The metadata key to retrieve.
* @param mixed $default_value Optional. The default value to return if the metadata item is not found. Default `null`.
* @return mixed The value of the metadata item, or the default value if not found.
*/
public function get_meta_item( string $key, $default_value = null ) {
return array_key_exists( $key, $this->meta ) ? $this->meta[ $key ] : $default_value;
}
/**
* Normalizes the input for the ability, applying the default value from the input schema when needed.
*
* When no input is provided and the input schema is defined with a top-level `default` key, this method returns
* the value of that key. If the input schema does not define a `default`, or if the input schema is empty,
* this method returns null. If input is provided, it is returned as-is.
*
* @since 6.9.0
*
* @param mixed $input Optional. The raw input provided for the ability. Default `null`.
* @return mixed The same input, or the default from schema, or `null` if default not set.
*/
public function normalize_input( $input = null ) {
if ( null !== $input ) {
return $input;
}
$input_schema = $this->get_input_schema();
if ( ! empty( $input_schema ) && array_key_exists( 'default', $input_schema ) ) {
return $input_schema['default'];
}
return null;
}
/**
* Validates input data against the input schema.
*
* @since 6.9.0
*
* @param mixed $input Optional. The input data to validate. Default `null`.
* @return true|WP_Error Returns true if valid or the WP_Error object if validation fails.
*/
public function validate_input( $input = null ) {
$input_schema = $this->get_input_schema();
if ( empty( $input_schema ) ) {
if ( null === $input ) {
return true;
}
return new WP_Error(
'ability_missing_input_schema',
sprintf(
/* translators: %s ability name. */
__( 'Ability "%s" does not define an input schema required to validate the provided input.' ),
esc_html( $this->name )
)
);
}
$valid_input = rest_validate_value_from_schema( $input, $input_schema, 'input' );
if ( is_wp_error( $valid_input ) ) {
return new WP_Error(
'ability_invalid_input',
sprintf(
/* translators: %1$s ability name, %2$s error message. */
__( 'Ability "%1$s" has invalid input. Reason: %2$s' ),
esc_html( $this->name ),
$valid_input->get_error_message()
)
);
}
return true;
}
/**
* Invokes a callable, ensuring the input is passed through only if the input schema is defined.
*
* @since 6.9.0
*
* @param callable $callback The callable to invoke.
* @param mixed $input Optional. The input data for the ability. Default `null`.
* @return mixed The result of the callable execution.
*/
protected function invoke_callback( callable $callback, $input = null ) {
$args = array();
if ( ! empty( $this->get_input_schema() ) ) {
$args[] = $input;
}
return $callback( ...$args );
}
/**
* Checks whether the ability has the necessary permissions.
*
* Please note that input is not automatically validated against the input schema.
* Use `validate_input()` method to validate input before calling this method if needed.
*
* @since 6.9.0
*
* @see validate_input()
*
* @param mixed $input Optional. The valid input data for permission checking. Default `null`.
* @return bool|WP_Error Whether the ability has the necessary permission.
*/
public function check_permissions( $input = null ) {
if ( ! is_callable( $this->permission_callback ) ) {
return new WP_Error(
'ability_invalid_permission_callback',
/* translators: %s ability name. */
sprintf( __( 'Ability "%s" does not have a valid permission callback.' ), esc_html( $this->name ) )
);
}
return $this->invoke_callback( $this->permission_callback, $input );
}
/**
* Executes the ability callback.
*
* @since 6.9.0
*
* @param mixed $input Optional. The input data for the ability. Default `null`.
* @return mixed|WP_Error The result of the ability execution, or WP_Error on failure.
*/
protected function do_execute( $input = null ) {
if ( ! is_callable( $this->execute_callback ) ) {
return new WP_Error(
'ability_invalid_execute_callback',
/* translators: %s ability name. */
sprintf( __( 'Ability "%s" does not have a valid execute callback.' ), esc_html( $this->name ) )
);
}
return $this->invoke_callback( $this->execute_callback, $input );
}
/**
* Validates output data against the output schema.
*
* @since 6.9.0
*
* @param mixed $output The output data to validate.
* @return true|WP_Error Returns true if valid, or a WP_Error object if validation fails.
*/
protected function validate_output( $output ) {
$output_schema = $this->get_output_schema();
if ( empty( $output_schema ) ) {
return true;
}
$valid_output = rest_validate_value_from_schema( $output, $output_schema, 'output' );
if ( is_wp_error( $valid_output ) ) {
return new WP_Error(
'ability_invalid_output',
sprintf(
/* translators: %1$s ability name, %2$s error message. */
__( 'Ability "%1$s" has invalid output. Reason: %2$s' ),
esc_html( $this->name ),
$valid_output->get_error_message()
)
);
}
return true;
}
/**
* Executes the ability after input validation and running a permission check.
* Before returning the return value, it also validates the output.
*
* @since 6.9.0
*
* @param mixed $input Optional. The input data for the ability. Default `null`.
* @return mixed|WP_Error The result of the ability execution, or WP_Error on failure.
*/
public function execute( $input = null ) {
$input = $this->normalize_input( $input );
$is_valid = $this->validate_input( $input );
if ( is_wp_error( $is_valid ) ) {
return $is_valid;
}
$has_permissions = $this->check_permissions( $input );
if ( true !== $has_permissions ) {
if ( is_wp_error( $has_permissions ) ) {
// Don't leak the permission check error to someone without the correct perms.
_doing_it_wrong(
__METHOD__,
esc_html( $has_permissions->get_error_message() ),
'6.9.0'
);
}
return new WP_Error(
'ability_invalid_permissions',
/* translators: %s ability name. */
sprintf( __( 'Ability "%s" does not have necessary permission.' ), esc_html( $this->name ) )
);
}
/**
* Fires before an ability gets executed, after input validation and permissions check.
*
* @since 6.9.0
*
* @param string $ability_name The name of the ability.
* @param mixed $input The input data for the ability.
*/
do_action( 'wp_before_execute_ability', $this->name, $input );
$result = $this->do_execute( $input );
if ( is_wp_error( $result ) ) {
return $result;
}
$is_valid = $this->validate_output( $result );
if ( is_wp_error( $is_valid ) ) {
return $is_valid;
}
/**
* Fires immediately after an ability finished executing.
*
* @since 6.9.0
*
* @param string $ability_name The name of the ability.
* @param mixed $input The input data for the ability.
* @param mixed $result The result of the ability execution.
*/
do_action( 'wp_after_execute_ability', $this->name, $input, $result );
return $result;
}
/**
* Wakeup magic method.
*
* @since 6.9.0
* @throws LogicException If the ability object is unserialized.
* This is a security hardening measure to prevent unserialization of the ability.
*/
public function __wakeup(): void {
throw new LogicException( __CLASS__ . ' should never be unserialized.' );
}
/**
* Sleep magic method.
*
* @since 6.9.0
* @throws LogicException If the ability object is serialized.
* This is a security hardening measure to prevent serialization of the ability.
*/
public function __sleep(): array {
throw new LogicException( __CLASS__ . ' should never be serialized.' );
}
}
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