Refactored the consumption of the API to use singular font family data

lib/experimental/fonts/font-library/class-wp-font-family.php

@@ -105,11 +105,9 @@
 	 */
 	public function uninstall() {
 		$post = $this->get_data_from_post();
-		if ( null === $post ) {
-			return new WP_Error(
-				'font_family_not_found',
-				__( 'The font family could not be found.', 'gutenberg' )
-			);
+
+		if ( is_wp_error( $post ) ) {
+			return $post;
 		}
 
 		if (
@@ -444,11 +442,11 @@
 
 		$posts_query = new WP_Query( $args );
 
-		if ( $posts_query->have_posts() ) {
-			return $posts_query->posts[0];
+		if ( ! $posts_query->have_posts() ) {
+			return null;
 		}
 
-		return null;
+		return $posts_query->posts[0];
 	}
 
 	/**
@@ -457,17 +455,36 @@
 	 *
 	 * @since 6.5.0
 	 *
-	 * @return WP_Post|null The post for this font family object or
-	 *                      null if the post does not exist.
+	 * @return WP_Post|WP_Error The post for this font family object if it exists and has valid JSON content.
 	 */
-	private function get_data_from_post() {
+	public function get_data_from_post() {
 		$post = $this->get_font_post();
-		if ( $post ) {
-			$this->data = json_decode( $post->post_content, true );
-			return $post;
+
+		if ( ! $post ) {
+			return new WP_Error(
+				'font_family_slug_not_found',
+				__( 'Font Family with that slug was not found.' ),
+				array(
+					'status' => 404,
+				)
+			);
+		}
+
+		$decoded_content = json_decode( $post->post_content, true );
+
+		if ( ! $decoded_content ) {
+			return new WP_Error(
+				'font_family_invalid_json_content',
+				__( 'The JSON content of the font family is invalid.' ),
+				array(
+					'status' => 500,
+				)
+			);
 		}
 
-		return null;
+		$this->data = $decoded_content;
+
+		return $post;
 	}
 
 	/**

lib/experimental/fonts/font-library/class-wp-font-library.php

@@ -89,7 +89,7 @@ public static function get_font_collections() {
 	 * @since 6.5.0
 	 *
 	 * @param string $id Font collection id.
-	 * @return array List of font collections.
+	 * @return WP_Font_Collection|WP_Error Font collection if it exists and a WP_Error otherwise.
 	 */
 	public static function get_font_collection( $id ) {
 		if ( array_key_exists( $id, self::$collections ) ) {

lib/experimental/fonts/font-library/class-wp-rest-font-collections-controller.php

@@ -0,0 +1,284 @@
+<?php
+/**
+ * Rest Font Collection Controller.
+ *
+ * This file contains the class for the REST API Font Collection Controller.
+ *
+ * @package    WordPress
+ * @subpackage Font Collection
+ * @since      6.4.0
+ */
+
+/**
+ * Font Collection Controller class.
+ *
+ * @since 6.4.0
+ */
+class WP_REST_Font_Collections_Controller extends WP_REST_Controller {
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 6.4.0
+	 */
+	public function __construct() {
+		$this->rest_base = 'font-collections';
+		$this->namespace = 'wp/v2';
+	}
+
+	/**
+	 * Registers the routes for the objects of the controller.
+	 *
+	 * @since 6.4.0
+	 */
+	public function register_routes() {
+		register_rest_route(
+			$this->namespace,
+			'/' . $this->rest_base,
+			array(
+				array(
+					'methods'             => WP_REST_Server::READABLE,
+					'callback'            => array( $this, 'get_items' ),
+					'permission_callback' => array( $this, 'update_font_library_permissions_check' ),
+				),
+				'schema' => array( $this, 'get_items_schema' ),
+			)
+		);
+
+		register_rest_route(
+			$this->namespace,
+			'/' . $this->rest_base . '/(?P<id>[\/\w-]+)',
+			array(
+				'args'   => array(
+					'id' => array(
+						'description' => __( 'Unique identifier for the post.' ),
+						'type'        => 'string',
+						'required'    => true,
+					),
+				),
+				array(
+					'methods'             => WP_REST_Server::READABLE,
+					'callback'            => array( $this, 'get_item' ),
+					'permission_callback' => array( $this, 'update_font_library_permissions_check' ),
+				),
+				'schema' => array( $this, 'get_item_schema' ),
+			)
+		);
+	}
+
+	/**
+	 * Gets a font collection.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
+	 */
+	public function get_item( $request ) {
+		$id         = $request['id'];
+		$collection = WP_Font_Library::get_font_collection( $id );
+		// If the collection doesn't exist returns a 404.
+		if ( is_wp_error( $collection ) ) {
+			$collection->add_data( array( 'status' => 404 ) );
+			return $collection;
+		}
+		$collection_with_data = $collection->get_data();
+		// If there was an error getting the collection data, return the error.
+		if ( is_wp_error( $collection_with_data ) ) {
+			$collection_with_data->add_data( array( 'status' => 500 ) );
+			return $collection_with_data;
+		}
+
+		return rest_ensure_response( $collection_with_data );
+	}
+
+	/**
+	 * Gets the font collections available.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @return WP_REST_Response Response object.
+	 */
+	public function get_items( $request ) {
+		$collections = array();
+		foreach ( WP_Font_Library::get_font_collections() as $collection ) {
+			$collections[] = $collection->get_config();
+		}
+
+		return new WP_REST_Response( $collections, 200 );
+	}
+
+	/**
+	 * Checks whether the user has permissions to update the Font Library.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @return true|WP_Error True if the request has write access for the item, WP_Error object otherwise.
+	 */
+	public function update_font_library_permissions_check() {
+		if ( ! current_user_can( 'edit_theme_options' ) ) {
+			return new WP_Error(
+				'rest_cannot_update_font_library',
+				__( 'Sorry, you are not allowed to update the Font Library on this site.' ),
+				array(
+					'status' => rest_authorization_required_code(),
+				)
+			);
+		}
+		return true;
+	}
+
+	/**
+	 * Retrieves the schema for the font collections item, conforming to JSON Schema.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @return array Item schema data.
+	 */
+	public function get_items_schema() {
+		if ( $this->schema ) {
+			return $this->add_additional_fields_schema( $this->schema );
+		}
+
+		$schema = array(
+			'$schema' => 'http://json-schema.org/draft-04/schema#',
+			'title'   => 'font-collections',
+			'type'    => 'array',
+			'items'   => array(
+				'type'       => 'object',
+				'properties' => array(
+					'id'          => array(
+						'description' => __( 'Unique identifier for the font collection.' ),
+						'type'        => 'string',
+						'context'     => array( 'view', 'edit', 'embed' ),
+						'readonly'    => true,
+					),
+					'name'        => array(
+						'description' => __( 'Name of the font collection.' ),
+						'type'        => 'string',
+						'context'     => array( 'view', 'edit', 'embed' ),
+					),
+					'description' => array(
+						'description' => __( 'Description of the font collection.' ),
+						'type'        => 'string',
+						'context'     => array( 'view', 'edit', 'embed' ),
+					),
+					'src'         => array(
+						'description' => __( 'Source to the list of font families.' ),
+						'type'        => 'string',
+						'context'     => array( 'view', 'edit', 'embed' ),
+					),
+				),
+			),
+		);
+
+		$this->schema = $schema;
+		return $this->add_additional_fields_schema( $this->schema );
+	}
+
+	/**
+	 * Retrieves the item's schema, conforming to JSON Schema.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @return array Item schema data.
+	 */
+	public function get_item_schema() {
+		if ( $this->schema ) {
+			return $this->add_additional_fields_schema( $this->schema );
+		}
+
+		$schema = array(
+			'$schema'    => 'http://json-schema.org/draft-04/schema#',
+			'title'      => 'font-collection',
+			'type'       => 'object',
+			'properties' => array(
+				'id'          => array(
+					'description' => __( 'Unique identifier for the font collection.' ),
+					'type'        => 'string',
+					'context'     => array( 'view', 'edit', 'embed' ),
+					'readonly'    => true,
+				),
+				'name'        => array(
+					'description' => __( 'Name of the font collection.' ),
+					'type'        => 'string',
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'description' => array(
+					'description' => __( 'Description of the font collection.' ),
+					'type'        => 'string',
+					'context'     => array( 'view', 'edit', 'embed' ),
+				),
+				'data'        => array(
+					'description' => __( 'Data of the font collection.' ),
+					'type'        => 'object',
+					'context'     => array( 'view', 'edit', 'embed' ),
+					'properties'  => array(
+						'font_families' => array(
+							'description' => __( 'List of font families.' ),
+							'type'        => 'array',
+							'items'       => array(
+								'type'       => 'object',
+								'properties' => array(
+									'name'        => array(
+										'description' => __( 'Name of the font family.' ),
+										'type'        => 'string',
+									),
+									'font_family' => array(
+										'description' => __( 'Font family string.' ),
+										'type'        => 'string',
+									),
+									'slug'        => array(
+										'description' => __( 'Slug of the font family.' ),
+										'type'        => 'string',
+									),
+									'category'    => array(
+										'description' => __( 'Category of the font family.' ),
+										'type'        => 'string',
+									),
+									'font_face'   => array(
+										'description' => __( 'Font face details.' ),
+										'type'        => 'array',
+										'items'       => array(
+											'type'       => 'object',
+											'properties' => array(
+												'download_from_url' => array(
+													'description' => __( 'URL to download the font.' ),
+													'type' => 'string',
+												),
+												'font_weight' => array(
+													'description' => __( 'Font weight.' ),
+													'type' => 'string',
+												),
+												'fonts_style' => array(
+													'description' => __( 'Font style.' ),
+													'type' => 'string',
+												),
+												'font_family' => array(
+													'description' => __( 'Font family string.' ),
+													'type' => 'string',
+												),
+												'preview' => array(
+													'description' => __( 'URL for font preview.' ),
+													'type' => 'string',
+												),
+											),
+										),
+									),
+									'preview'     => array(
+										'description' => __( 'URL for font family preview.' ),
+										'type'        => 'string',
+									),
+								),
+							),
+						),
+					),
+				),
+			),
+		);
+
+		$this->schema = $schema;
+		return $this->add_additional_fields_schema( $this->schema );
+	}
+}