Embeds: Improve performance when embedding a post from the current site.

When the post being embedded is from the same site, there's no reason to do an HTTP request for it. The data can be fetched directly using `get_oembed_response_data()`.

Fixes #36767 for trunk.

git-svn-id: https://develop.svn.wordpress.org/trunk@37708 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-oembed.php

@@ -315,10 +315,32 @@ class WP_oEmbed {
 	 * @return false|string False on failure, otherwise the UNSANITIZED (and potentially unsafe) HTML that should be used to embed.
 	 */
 	public function get_html( $url, $args = '' ) {
+		/**
+		 * Filters the oEmbed result before any HTTP requests are made.
+		 *
+		 * This allows one to short-circuit the default logic, perhaps by
+		 * replacing it with a routine that is more optimal for your setup.
+		 *
+		 * Passing a non-null value to the filter will effectively short-circuit retrieval,
+		 * returning the passed value instead.
+		 *
+		 * @since 4.5.3
+		 *
+		 * @param null|string $result The UNSANITIZED (and potentially unsafe) HTML that should be used to embed. Default null.
+		 * @param string      $url    The URL to the content that should be attempted to be embedded.
+		 * @param array       $args   Optional. Arguments, usually passed from a shortcode. Default empty.
+		 */
+		$pre = apply_filters( 'pre_oembed_result', null, $url, $args );
+
+		if ( null !== $pre ) {
+			return $pre;
+		}
+
 		$provider = $this->get_provider( $url, $args );
 
-		if ( !$provider || false === $data = $this->fetch( $provider, $url, $args ) )
+		if ( ! $provider || false === $data = $this->fetch( $provider, $url, $args ) ) {
 			return false;
+		}
 
 		/**
 		 * Filters the HTML returned by the oEmbed provider.

src/wp-includes/default-filters.php

@@ -476,5 +476,6 @@ add_filter( 'the_excerpt_embed',      'wp_embed_excerpt_attachment'           );
 
 add_filter( 'oembed_dataparse',       'wp_filter_oembed_result',        10, 3 );
 add_filter( 'oembed_response_data',   'get_oembed_response_data_rich',  10, 4 );
+add_filter( 'pre_oembed_result',      'wp_filter_pre_oembed_result',    10, 3 );
 
 unset( $filter, $action );

src/wp-includes/embed.php

@@ -1079,3 +1079,35 @@ function the_embed_site_title() {
 	 */
 	echo apply_filters( 'embed_site_title_html', $site_title );
 }
+
+/**
+ * Filters the oEmbed result before any HTTP requests are made.
+ *
+ * If the URL belongs to the current site, the result is fetched directly instead of
+ * going through the oEmbed discovery process.
+ *
+ * @since 4.5.3
+ *
+ * @param null|string $result The UNSANITIZED (and potentially unsafe) HTML that should be used to embed. Default null.
+ * @param string      $url    The URL that should be inspected for discovery `<link>` tags.
+ * @param array       $args   oEmbed remote get arguments.
+ * @return null|string The UNSANITIZED (and potentially unsafe) HTML that should be used to embed.
+ *                     Null if the URL does not belong to the current site.
+ */
+function wp_filter_pre_oembed_result( $result, $url, $args ) {
+	$post_id = url_to_postid( $url );
+
+	/** This filter is documented in wp-includes/class-wp-oembed-controller.php */
+	$post_id = apply_filters( 'oembed_request_post_id', $post_id, $url );
+
+	$width = isset( $args['width'] ) ? $args['width'] : 0;
+
+	$data = get_oembed_response_data( $post_id, $width );
+	$data = _wp_oembed_get_object()->data2html( (object) $data, $url );
+
+	if ( ! $data ) {
+		return $result;
+	}
+
+	return $data;
+}

tests/phpunit/tests/oembed/wpOembed.php

@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * @group oembed
+ */
+class Tests_WP_oEmbed extends WP_UnitTestCase {
+	/**
+	 * @var WP_oEmbed
+	 */
+	protected $oembed;
+
+	public $pre_oembed_result_filtered = false;
+
+	public function setUp() {
+		parent::setUp();
+
+		require_once ABSPATH . WPINC . '/class-oembed.php';
+		$this->oembed = _wp_oembed_get_object();
+
+		$this->pre_oembed_result_filtered = false;
+	}
+
+	public function _filter_pre_oembed_result( $result ) {
+		// If this is not null, the oEmbed result has been filtered before any HTTP requests were made.
+		$this->pre_oembed_result_filtered = $result;
+
+		return $result;
+	}
+
+	public function test_wp_filter_pre_oembed_result_prevents_http_request_for_internal_permalinks() {
+		$post_id   = self::factory()->post->create();
+		$permalink = get_permalink( $post_id );
+
+		add_filter( 'pre_oembed_result', array( $this, '_filter_pre_oembed_result' ) );
+		$actual = $this->oembed->get_html( $permalink );
+		remove_filter( 'pre_oembed_result', array( $this, '_filter_pre_oembed_result' ) );
+
+		$this->assertNotFalse( $this->pre_oembed_result_filtered );
+		$this->assertEquals( $this->pre_oembed_result_filtered, $actual );
+	}
+
+	public function test_wp_filter_pre_oembed_result_prevents_http_request_when_viewing_the_post() {
+		$post_id   = self::factory()->post->create();
+		$permalink = get_permalink( $post_id );
+
+		$this->go_to( $permalink );
+		$this->assertQueryTrue( 'is_single', 'is_singular' );
+
+		add_filter( 'pre_oembed_result', array( $this, '_filter_pre_oembed_result' ) );
+		$actual = $this->oembed->get_html( $permalink );
+		remove_filter( 'pre_oembed_result', array( $this, '_filter_pre_oembed_result' ) );
+
+		$this->assertNotFalse( $this->pre_oembed_result_filtered );
+		$this->assertEquals( $this->pre_oembed_result_filtered, $actual );
+	}
+}