Gutenberg WPGraphQL - Page Template GraphQL Fields

gutenberg-wpgraphql-page-template-graphql-fields.php

/**
 * Adds a field to the Page type in the GraphQL Schema to allow for the page's "blockTemplate" to be fetched and
 * returned.
 */
add_filter( 'graphql_page_fields', function( $fields ) {

	$fields['blockTemplate'] = [
		'type' => \WPGraphQL\Types::string(),
		'description' => __( 'The Block template defined for the page', 'oshpd-guten-blocks' ),
		'args' => [
			'pageTemplate' => [
				'type' => \WPGraphQL\Types::string(),
				'description' => __( 'The page template associated with the block template', 'oshpd-guten-blocks' ),
			],
		],
		'resolve' => function( \WP_Post $post, array $args, $info, $context ) {

			$page_template = ! empty( $args['pageTemplate'] ) ? $args['pageTemplate'] : get_page_template_slug( $post->ID );
			$saved_block_template = ! empty( $page_template ) ? get_post_meta( $post->ID, '_saved_block_template_' . $page_template, true ) : null;

			if ( ! empty ( $saved_block_template ) ) {
				$template = $saved_block_template;
			} else {
				$template = oshpd_get_default_page_block_template( $page_template );
			}

			return $template;
		}
	];

	return $fields;

} );

add_action( 'do_graphql_request', function() {

	/**
	 * Define the PageTemplateBlockTemplate input field to allow for block template content to be persisted when
	 * switching templates.
	 */
	$block_template_input = new \WPGraphQL\Type\WPInputObjectType([
		'name' => 'PageTemplateBlockTemplate',
		'description' => __( 'Allows for content to be persisted when page templates are switched', 'oshpd-guten-blocks' ),
		'fields' => [
			'pageTemplateSlug' => [
				'type' => \WPGraphQL\Types::non_null( \WPGraphQL\Types::string() ),
				'description' => __( 'The Page Template the content is connected to', 'oshpd-guten-blocks' ),
			],
			'content' => [
				'type' => \WPGraphQL\Types::non_null( \WPGraphQL\Types::string() ),
				'description' => __( 'The content that should be stored in connection with the page template', 'oshpd-guten-blocks' ),
			],
		],
	]);

	/**
	 * Filter in the blockTemplate field into the upda
	 */
	add_filter( 'graphql_post_object_mutation_input_fields', function( $fields, $post_type_object ) use ( $block_template_input ) {

		/**
		 * Only add this to post types that support page attributes.
		 */
		if ( post_type_supports( $post_type_object->name, 'page-attributes' ) ) {
			$fields['blockTemplate'] = [
				'type'        => $block_template_input,
				'description' => __( 'Persist content entered for a particular page template', 'oshpd-guten-blocks' )
			];
		}

		return $fields;

	}, 10, 2 );

});

/**
 * Hook into the PostObject update mutation and save the page_template content to meta.
 */
add_action( 'graphql_post_object_mutation_update_additional_data', function( $post_id, $input, $post_type_object, $mutation_name, $context, $info ) {

	if ( ! empty( $input['blockTemplate']['pageTemplateSlug'] ) && ! empty( $input['blockTemplate']['content'] ) ) {
		$content = preg_replace( "/\r|\n|\t/", "", $input['blockTemplate']['content'] );
		update_post_meta( $post_id, '_saved_block_template_' . $input['blockTemplate']['pageTemplateSlug'], $content );
	}

}, 10, 6 );

/**
 * Returns the block template associated with a particular page template
 *
 * @param string $page_template The slug of the page template (ex: templates/page-template.php)
 * @return string The block template
 */
function oshpd_get_default_page_block_template( $page_template ) {

	$block_template = '';

	switch ( $page_template ) {
		case 'templates/home.php':
			$block_template = '
			<!-- wp:oshpd/homepage-hero /-->
			<!-- wp:oshpd/latest-news /-->
			<!-- wp:oshpd/leadership-cards /-->
			';
			break;
		case 'templates/landing-page.php':
			$block_template = '
			<!-- wp:oshpd/leadership-cards /-->
			<!-- wp:oshpd/homepage-hero /-->
			';
			break;
	}

	$filtered_template = apply_filters( 'oshpd_get_default_page_block_template', $block_template, $page_template );
	return preg_replace( "/\r|\n|\t/", "", $filtered_template );

}