Only load front end CSS when it is needed (#1455)

* Only load front end CSS when it is needed

This checks to make sure that a Coblock is being used before requiring the CSS to be loaded on the front end of the site.  This is to address #1454 

In my basic tests this worked fine, however I'd like to see it get broader testing to make sure I haven't missed other conditions.

* Define $post global and don't overwrite it

* Ensure assets load when block editor is used.

* Only check post content if not in the admin

* Resolve failing tests

* Adding tests

* Updating contributors

Co-authored-by: JR Tashjian <jrtashjian@gmail.com>

.dev/tests/phpunit/includes/test-coblocks-block-assets.php

@@ -126,6 +126,44 @@ public function test_editor_assets_localized_data() {
 
 	}
 
+	public function test_block_assets_not_loaded_when_no_coblocks_block() {
+		global $post, $wp_styles;
+		unset( $GLOBALS['current_screen'] );
+
+		$post_id = wp_insert_post( [
+			'post_author'  => 1,
+			'post_content' => 'NoBlocks',
+			'post_title'   => 'NoBlocks',
+			'post_status'  => 'publish',
+		] );
+
+		$post = get_post( $post_id );
+
+		$this->coblocks_block_assets->block_assets();
+		do_action( 'enqueue_block_assets' );
+
+		$this->assertNotContains( 'coblocks-frontend', $wp_styles->queue );
+	}
+
+	public function test_block_assets_loaded_with_coblocks_block() {
+		global $post, $wp_styles;
+		unset( $GLOBALS['current_screen'] );
+
+		$post_id = wp_insert_post( [
+			'post_author'  => 1,
+			'post_content' => '<!-- wp:coblocks/hasblocks --><!-- /wp:coblocks/hasblocks -->',
+			'post_title'   => 'CoBlocks',
+			'post_status'  => 'publish',
+		] );
+
+		$post = get_post( $post_id );
+
+		$this->coblocks_block_assets->block_assets();
+		do_action( 'enqueue_block_assets' );
+
+		$this->assertContains( 'coblocks-frontend', $wp_styles->queue );
+	}
+
 	/**
 	 * Test the frontend scripts masonry are enqueued correctly
 	 */

.dev/tests/phpunit/includes/test-coblocks-generated-styles.php

@@ -7,6 +7,7 @@
 class CoBlocks_Generated_Styles_Tests extends WP_UnitTestCase {
 
 	private $coblocks_generated_styles;
+	private $coblocks_block_assets;
 
 	private $dimensions;
 
@@ -46,6 +47,7 @@ public function setUp() {
 		];
 
 		$this->coblocks_generated_styles = new CoBlocks_Generated_Styles();
+		$this->coblocks_block_assets = new CoBlocks_Block_Assets();
 
 	}
 
@@ -105,10 +107,12 @@ public function test_construct_actions() {
 	 */
 	public function test_enqueue_styles() {
 
+		unset( $GLOBALS['current_screen'] );
+
 		$post_id = wp_insert_post(
 			[
 				'post_author'  => 1,
-				'post_content' => 'Post content',
+				'post_content' => '<!-- wp:coblocks/block_with_custom_styles --><!-- /wp:coblocks/block_with_custom_styles -->',
 				'post_title'   => 'Post title',
 				'post_status'  => 'publish',
 			]
@@ -121,8 +125,10 @@ public function test_enqueue_styles() {
 
 		$post = get_post( $post_id );
 
+		$this->coblocks_block_assets->block_assets();
 		$this->coblocks_generated_styles->enqueue_styles();
 
+		do_action( 'enqueue_block_assets' );
 		do_action( 'wp_enqueue_scripts' );
 
 		global $wp_styles;

CONTRIBUTORS.md

@@ -28,4 +28,5 @@ This list is manually curated to include valuable contributions by volunteers th
 | @p-jackson      |                        |
 | @gmays          |                        |
 | @brandonpayton  |                        |
+| @josephscott    | @josephscott           |
 | @passatgt       | @passatgt              |

includes/class-coblocks-block-assets.php

@@ -74,6 +74,27 @@ public function get_asset_file( $filepath ) {
 	 * @access public
 	 */
 	public function block_assets() {
+		global $post;
+
+		// Only load the front end CSS if a Coblock is in use.
+		$has_coblock = false;
+
+		if ( ! is_admin() ) {
+			// This is similar to has_block() in core, but will match anything
+			// in the coblocks/* namespace.
+			$wp_post = get_post( $post );
+			if ( $wp_post instanceof WP_Post ) {
+				$post_content = $wp_post->post_content;
+			}
+
+			if ( false !== strpos( $post_content, '<!-- wp:coblocks/' ) ) {
+				$has_coblock = true;
+			}
+		}
+
+		if ( ! $has_coblock && ! $this->is_page_gutenberg() ) {
+			return;
+		}
 
 		// Styles.
 		$name       = 'coblocks-style';
@@ -360,6 +381,50 @@ public function editor_scripts() {
 			true
 		);
 	}
+
+	/**
+	 * Return whether a post type should display the Block Editor.
+	 *
+	 * @param string $post_type The post_type slug to check.
+	 */
+	protected function is_post_type_gutenberg( $post_type ) {
+		return use_block_editor_for_post_type( $post_type );
+	}
+
+	/**
+	 * Return whether the page we are on is loading the Block Editor.
+	 */
+	protected function is_page_gutenberg() {
+		if ( ! is_admin() ) {
+			return false;
+		}
+
+		$admin_page = wp_basename( esc_url( $_SERVER['REQUEST_URI'] ) );
+
+		if ( false !== strpos( $admin_page, 'post-new.php' ) && empty( $_GET['post_type'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			return true;
+		}
+
+		if ( false !== strpos( $admin_page, 'post-new.php' ) && isset( $_GET['post_type'] ) && $this->is_post_type_gutenberg( $_GET['post_type'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			return true;
+		}
+
+		if ( false !== strpos( $admin_page, 'post.php' ) ) {
+			$wp_post = get_post( $_GET['post'] ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			if ( isset( $wp_post ) && isset( $wp_post->post_type ) && $this->is_post_type_gutenberg( $wp_post->post_type ) ) {
+				return true;
+			}
+		}
+
+		if ( false !== strpos( $admin_page, 'revision.php' ) ) {
+			$wp_post     = get_post( $_GET['revision'] ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			$post_parent = get_post( $wp_post->post_parent );
+			if ( isset( $post_parent ) && isset( $post_parent->post_type ) && $this->is_post_type_gutenberg( $post_parent->post_type ) ) {
+				return true;
+			}
+		}
+		return false;
+	}
 }
 
 CoBlocks_Block_Assets::register();