acf_get_field_json_schema() │ ACF 6.8.0

Retrieves the JSON schema for a field.

No Hooks.

Returns

Array.

Usage

acf_get_field_json_schema( $field_type ): array;

$field_type(string) (required)

The field to get the JSON schema for.

Changelog

acf_get_field_json_schema() acf get field json schema code ^{ACF 6.8.8}

function acf_get_field_json_schema( string $field_type ): array {
	// Check store cache first.
	$store = acf_get_store( 'field-type-schemas' );
	if ( $store->has( $field_type ) ) {
		return $store->get( $field_type );
	}

	$schema = array();

	// Sanitize field name to prevent directory traversal.
	$safe_name = preg_replace( '/[^a-z0-9_-]/i', '', $field_type );

	// Early return if sanitization removed the name.
	if ( empty( $safe_name ) || $safe_name !== $field_type ) {
		// Cache the empty result to avoid repeated validation attempts.
		$store->set( $field_type, $schema );
		return $schema;
	}

	// Build schema file path.
	$schema_file = ACF_PATH . 'schemas/fields/v1/' . $safe_name . '.json';

	// Get cached schema directory path or compute it once.
	$real_schema_dir = $store->has( '_schema_dir' )
		? $store->get( '_schema_dir' )
		: realpath( ACF_PATH . 'schemas/fields/v1/' );

	// Cache the schema directory for subsequent calls.
	if ( ! $store->has( '_schema_dir' ) && $real_schema_dir ) {
		$store->set( '_schema_dir', $real_schema_dir );
	}

	// Verify the resolved path is within the expected directory (security check).
	$real_schema_path = realpath( $schema_file );

	if ( ! $real_schema_path || ! $real_schema_dir || strpos( $real_schema_path, $real_schema_dir ) !== 0 ) {
		// Cache the empty result to avoid repeated file system checks.
		$store->set( $field_type, array() );
		return array();
	}

	// Read and parse JSON file.
	$json_content = wp_json_file_decode( $real_schema_path, array( 'associative' => true ) );

	if ( is_array( $json_content ) ) {
		$schema = $json_content;

		// Remove JSON Schema meta properties not needed for WordPress REST API validation.
		unset( $schema['$schema'], $schema['$id'] );
	}

	// Cache the parsed schema.
	$store->set( $field_type, $schema );

	return $schema;
}