]> scripts.mit.edu Git - autoinstalls/wordpress.git/blobdiff - wp-includes/class-oembed.php
WordPress 4.6.3-scripts
[autoinstalls/wordpress.git] / wp-includes / class-oembed.php
index a880448db3f0e674a5c9c7079940a6f9dff48dbf..9790d266f67b6532410ac24adcb16df80f3331a2 100644 (file)
@@ -1,9 +1,10 @@
 <?php
 /**
- * API for fetching the HTML to embed remote content based on a provided URL.
- * Used internally by the {@link WP_Embed} class, but is designed to be generic.
+ * API for fetching the HTML to embed remote content based on a provided URL
  *
- * @link http://codex.wordpress.org/oEmbed oEmbed Codex Article
+ * Used internally by the WP_Embed class, but is designed to be generic.
+ *
+ * @link https://codex.wordpress.org/oEmbed oEmbed Codex Article
  * @link http://oembed.com/ oEmbed Homepage
  *
  * @package WordPress
  */
 
 /**
- * oEmbed class.
+ * Core class used to implement oEmbed functionality.
  *
- * @package WordPress
- * @subpackage oEmbed
  * @since 2.9.0
  */
 class WP_oEmbed {
-       var $providers = array();
 
        /**
-        * Constructor
+        * A list of oEmbed providers.
+        *
+        * @since 2.9.0
+        * @access public
+        * @var array
+        */
+       public $providers = array();
+
+       /**
+        * A list of an early oEmbed providers.
+        *
+        * @since 4.0.0
+        * @access public
+        * @static
+        * @var array
+        */
+       public static $early_providers = array();
+
+       /**
+        * A list of private/protected methods, used for backward compatibility.
+        *
+        * @since 4.2.0
+        * @access private
+        * @var array
+        */
+       private $compat_methods = array( '_fetch_with_format', '_parse_json', '_parse_xml', '_parse_body' );
+
+       /**
+        * Constructor.
         *
-        * @uses apply_filters() Filters a list of pre-defined oEmbed providers.
+        * @since 2.9.0
+        * @access public
         */
-       function __construct() {
-               // List out some popular sites that support oEmbed.
-               // The WP_Embed class disables discovery for non-unfiltered_html users, so only providers in this array will be used for them.
-               // Add to this list using the wp_oembed_add_provider() function (see its PHPDoc for details).
-               $this->providers = apply_filters( 'oembed_providers', array(
-                       '#https?://(www\.)?youtube\.com/watch.*#i'           => array( 'http://www.youtube.com/oembed',                     true  ),
-                       'http://youtu.be/*'                                  => array( 'http://www.youtube.com/oembed',                     false ),
-                       'http://blip.tv/*'                                   => array( 'http://blip.tv/oembed/',                            false ),
-                       '#https?://(www\.)?vimeo\.com/.*#i'                  => array( 'http://vimeo.com/api/oembed.{format}',              true  ),
-                       '#https?://(www\.)?dailymotion\.com/.*#i'            => array( 'http://www.dailymotion.com/services/oembed',        true  ),
-                       'http://dai.ly/*'                                    => array( 'http://www.dailymotion.com/services/oembed',        false ),
-                       '#https?://(www\.)?flickr\.com/.*#i'                 => array( 'http://www.flickr.com/services/oembed/',            true  ),
-                       'http://flic.kr/*'                                   => array( 'http://www.flickr.com/services/oembed/',            false ),
-                       '#https?://(.+\.)?smugmug\.com/.*#i'                 => array( 'http://api.smugmug.com/services/oembed/',           true  ),
-                       '#https?://(www\.)?hulu\.com/watch/.*#i'             => array( 'http://www.hulu.com/api/oembed.{format}',           true  ),
-                       '#https?://(www\.)?viddler\.com/.*#i'                => array( 'http://lab.viddler.com/services/oembed/',           true  ),
-                       'http://qik.com/*'                                   => array( 'http://qik.com/api/oembed.{format}',                false ),
-                       'http://revision3.com/*'                             => array( 'http://revision3.com/api/oembed/',                  false ),
-                       'http://i*.photobucket.com/albums/*'                 => array( 'http://photobucket.com/oembed',                     false ),
-                       'http://gi*.photobucket.com/groups/*'                => array( 'http://photobucket.com/oembed',                     false ),
-                       '#https?://(www\.)?scribd\.com/.*#i'                 => array( 'http://www.scribd.com/services/oembed',             true  ),
-                       'http://wordpress.tv/*'                              => array( 'http://wordpress.tv/oembed/',                       false ),
-                       '#https?://(.+\.)?polldaddy\.com/.*#i'               => array( 'http://polldaddy.com/oembed/',                      true  ),
-                       '#https?://(www\.)?funnyordie\.com/videos/.*#i'      => array( 'http://www.funnyordie.com/oembed',                  true  ),
-                       '#https?://(www\.)?twitter\.com/.+?/status(es)?/.*#i'=> array( 'http://api.twitter.com/1/statuses/oembed.{format}', true  ),
-                       '#https?://(www\.)?soundcloud\.com/.*#i'             => array( 'http://soundcloud.com/oembed',                      true  ),
-                       '#https?://(www\.)?slideshare\.net/*#'               => array( 'http://www.slideshare.net/api/oembed/2',            true  ),
-                       '#http://instagr(\.am|am\.com)/p/.*#i'               => array( 'http://api.instagram.com/oembed',                   true  ),
-                       '#https?://(www\.)?rdio\.com/.*#i'                   => array( 'http://www.rdio.com/api/oembed/',                   true  ),
-                       '#https?://rd\.io/x/.*#i'                            => array( 'http://www.rdio.com/api/oembed/',                   true  ),
-                       '#https?://(open|play)\.spotify\.com/.*#i'           => array( 'https://embed.spotify.com/oembed/',                 true  ),
-               ) );
+       public function __construct() {
+               $host = urlencode( home_url() );
+               $providers = array(
+                       '#http://((m|www)\.)?youtube\.com/watch.*#i'          => array( 'http://www.youtube.com/oembed',                             true  ),
+                       '#https://((m|www)\.)?youtube\.com/watch.*#i'         => array( 'http://www.youtube.com/oembed?scheme=https',                true  ),
+                       '#http://((m|www)\.)?youtube\.com/playlist.*#i'       => array( 'http://www.youtube.com/oembed',                             true  ),
+                       '#https://((m|www)\.)?youtube\.com/playlist.*#i'      => array( 'http://www.youtube.com/oembed?scheme=https',                true  ),
+                       '#http://youtu\.be/.*#i'                              => array( 'http://www.youtube.com/oembed',                             true  ),
+                       '#https://youtu\.be/.*#i'                             => array( 'http://www.youtube.com/oembed?scheme=https',                true  ),
+                       '#https?://(.+\.)?vimeo\.com/.*#i'                    => array( 'http://vimeo.com/api/oembed.{format}',                      true  ),
+                       '#https?://(www\.)?dailymotion\.com/.*#i'             => array( 'https://www.dailymotion.com/services/oembed',               true  ),
+                       '#https?://dai.ly/.*#i'                               => array( 'https://www.dailymotion.com/services/oembed',               true  ),
+                       '#https?://(www\.)?flickr\.com/.*#i'                  => array( 'https://www.flickr.com/services/oembed/',                   true  ),
+                       '#https?://flic\.kr/.*#i'                             => array( 'https://www.flickr.com/services/oembed/',                   true  ),
+                       '#https?://(.+\.)?smugmug\.com/.*#i'                  => array( 'http://api.smugmug.com/services/oembed/',                   true  ),
+                       '#https?://(www\.)?hulu\.com/watch/.*#i'              => array( 'http://www.hulu.com/api/oembed.{format}',                   true  ),
+                       'http://i*.photobucket.com/albums/*'                  => array( 'http://api.photobucket.com/oembed',                         false ),
+                       'http://gi*.photobucket.com/groups/*'                 => array( 'http://api.photobucket.com/oembed',                         false ),
+                       '#https?://(www\.)?scribd\.com/doc/.*#i'              => array( 'http://www.scribd.com/services/oembed',                     true  ),
+                       '#https?://wordpress.tv/.*#i'                         => array( 'http://wordpress.tv/oembed/',                               true  ),
+                       '#https?://(.+\.)?polldaddy\.com/.*#i'                => array( 'https://polldaddy.com/oembed/',                             true  ),
+                       '#https?://poll\.fm/.*#i'                             => array( 'https://polldaddy.com/oembed/',                             true  ),
+                       '#https?://(www\.)?funnyordie\.com/videos/.*#i'       => array( 'http://www.funnyordie.com/oembed',                          true  ),
+                       '#https?://(www\.)?twitter\.com/.+?/status(es)?/.*#i' => array( 'https://publish.twitter.com/oembed',                        true  ),
+                       '#https?://(www\.)?twitter\.com/.+?/timelines/.*#i'   => array( 'https://publish.twitter.com/oembed',                        true  ),
+                       '#https?://(www\.)?twitter\.com/i/moments/.*#i'       => array( 'https://publish.twitter.com/oembed',                        true  ),
+                       '#https?://vine.co/v/.*#i'                            => array( 'https://vine.co/oembed.{format}',                           true  ),
+                       '#https?://(www\.)?soundcloud\.com/.*#i'              => array( 'http://soundcloud.com/oembed',                              true  ),
+                       '#https?://(.+?\.)?slideshare\.net/.*#i'              => array( 'https://www.slideshare.net/api/oembed/2',                   true  ),
+                       '#https?://(www\.)?instagr(\.am|am\.com)/p/.*#i'      => array( 'https://api.instagram.com/oembed',                          true  ),
+                       '#https?://(open|play)\.spotify\.com/.*#i'            => array( 'https://embed.spotify.com/oembed/',                         true  ),
+                       '#https?://(.+\.)?imgur\.com/.*#i'                    => array( 'http://api.imgur.com/oembed',                               true  ),
+                       '#https?://(www\.)?meetu(\.ps|p\.com)/.*#i'           => array( 'http://api.meetup.com/oembed',                              true  ),
+                       '#https?://(www\.)?issuu\.com/.+/docs/.+#i'           => array( 'http://issuu.com/oembed_wp',                                true  ),
+                       '#https?://(www\.)?collegehumor\.com/video/.*#i'      => array( 'http://www.collegehumor.com/oembed.{format}',               true  ),
+                       '#https?://(www\.)?mixcloud\.com/.*#i'                => array( 'http://www.mixcloud.com/oembed',                            true  ),
+                       '#https?://(www\.|embed\.)?ted\.com/talks/.*#i'       => array( 'http://www.ted.com/talks/oembed.{format}',                  true  ),
+                       '#https?://(www\.)?(animoto|video214)\.com/play/.*#i' => array( 'https://animoto.com/oembeds/create',                        true  ),
+                       '#https?://(.+)\.tumblr\.com/post/.*#i'               => array( 'https://www.tumblr.com/oembed/1.0',                         true  ),
+                       '#https?://(www\.)?kickstarter\.com/projects/.*#i'    => array( 'https://www.kickstarter.com/services/oembed',               true  ),
+                       '#https?://kck\.st/.*#i'                              => array( 'https://www.kickstarter.com/services/oembed',               true  ),
+                       '#https?://cloudup\.com/.*#i'                         => array( 'https://cloudup.com/oembed',                                true  ),
+                       '#https?://(www\.)?reverbnation\.com/.*#i'            => array( 'https://www.reverbnation.com/oembed',                       true  ),
+                       '#https?://videopress.com/v/.*#'                      => array( 'https://public-api.wordpress.com/oembed/1.0/?for=' . $host, true  ),
+                       '#https?://(www\.)?reddit\.com/r/[^/]+/comments/.*#i' => array( 'https://www.reddit.com/oembed',                             true  ),
+                       '#https?://(www\.)?speakerdeck\.com/.*#i'             => array( 'https://speakerdeck.com/oembed.{format}',                   true  ),
+               );
+
+               if ( ! empty( self::$early_providers['add'] ) ) {
+                       foreach ( self::$early_providers['add'] as $format => $data ) {
+                               $providers[ $format ] = $data;
+                       }
+               }
+
+               if ( ! empty( self::$early_providers['remove'] ) ) {
+                       foreach ( self::$early_providers['remove'] as $format ) {
+                               unset( $providers[ $format ] );
+                       }
+               }
+
+               self::$early_providers = array();
+
+               /**
+                * Filters the list of whitelisted oEmbed providers.
+                *
+                * Since WordPress 4.4, oEmbed discovery is enabled for all users and allows embedding of sanitized
+                * iframes. The providers in this list are whitelisted, meaning they are trusted and allowed to
+                * embed any content, such as iframes, videos, JavaScript, and arbitrary HTML.
+                *
+                * Supported providers:
+                *
+                * |   Provider   |        Flavor         | Supports HTTPS |   Since   |
+                * | ------------ | --------------------- | :------------: | --------- |
+                * | Dailymotion  | dailymotion.com       |      Yes       | 2.9.0     |
+                * | Flickr       | flickr.com            |      Yes       | 2.9.0     |
+                * | Hulu         | hulu.com              |      Yes       | 2.9.0     |
+                * | Photobucket  | photobucket.com       |      No        | 2.9.0     |
+                * | Scribd       | scribd.com            |      Yes       | 2.9.0     |
+                * | Vimeo        | vimeo.com             |      Yes       | 2.9.0     |
+                * | WordPress.tv | wordpress.tv          |      Yes       | 2.9.0     |
+                * | YouTube      | youtube.com/watch     |      Yes       | 2.9.0     |
+                * | Funny or Die | funnyordie.com        |      Yes       | 3.0.0     |
+                * | Polldaddy    | polldaddy.com         |      Yes       | 3.0.0     |
+                * | SmugMug      | smugmug.com           |      Yes       | 3.0.0     |
+                * | YouTube      | youtu.be              |      Yes       | 3.0.0     |
+                * | Twitter      | twitter.com           |      Yes       | 3.4.0     |
+                * | Instagram    | instagram.com         |      Yes       | 3.5.0     |
+                * | Instagram    | instagr.am            |      Yes       | 3.5.0     |
+                * | Slideshare   | slideshare.net        |      Yes       | 3.5.0     |
+                * | SoundCloud   | soundcloud.com        |      Yes       | 3.5.0     |
+                * | Dailymotion  | dai.ly                |      Yes       | 3.6.0     |
+                * | Flickr       | flic.kr               |      Yes       | 3.6.0     |
+                * | Spotify      | spotify.com           |      Yes       | 3.6.0     |
+                * | Imgur        | imgur.com             |      Yes       | 3.9.0     |
+                * | Meetup.com   | meetup.com            |      Yes       | 3.9.0     |
+                * | Meetup.com   | meetu.ps              |      Yes       | 3.9.0     |
+                * | Animoto      | animoto.com           |      Yes       | 4.0.0     |
+                * | Animoto      | video214.com          |      Yes       | 4.0.0     |
+                * | CollegeHumor | collegehumor.com      |      Yes       | 4.0.0     |
+                * | Issuu        | issuu.com             |      Yes       | 4.0.0     |
+                * | Mixcloud     | mixcloud.com          |      Yes       | 4.0.0     |
+                * | Polldaddy    | poll.fm               |      Yes       | 4.0.0     |
+                * | TED          | ted.com               |      Yes       | 4.0.0     |
+                * | YouTube      | youtube.com/playlist  |      Yes       | 4.0.0     |
+                * | Vine         | vine.co               |      Yes       | 4.1.0     |
+                * | Tumblr       | tumblr.com            |      Yes       | 4.2.0     |
+                * | Kickstarter  | kickstarter.com       |      Yes       | 4.2.0     |
+                * | Kickstarter  | kck.st                |      Yes       | 4.2.0     |
+                * | Cloudup      | cloudup.com           |      Yes       | 4.4.0     |
+                * | ReverbNation | reverbnation.com      |      Yes       | 4.4.0     |
+                * | VideoPress   | videopress.com        |      Yes       | 4.4.0     |
+                * | Reddit       | reddit.com            |      Yes       | 4.4.0     |
+                * | Speaker Deck | speakerdeck.com       |      Yes       | 4.4.0     |
+                * | Twitter      | twitter.com/timelines |      Yes       | 4.5.0     |
+                * | Twitter      | twitter.com/moments   |      Yes       | 4.5.0     |
+                *
+                * No longer supported providers:
+                *
+                * |   Provider   |        Flavor        | Supports HTTPS |   Since   |  Removed  |
+                * | ------------ | -------------------- | :------------: | --------- | --------- |
+                * | Qik          | qik.com              |      Yes       | 2.9.0     | 3.9.0     |
+                * | Viddler      | viddler.com          |      Yes       | 2.9.0     | 4.0.0     |
+                * | Revision3    | revision3.com        |      No        | 2.9.0     | 4.2.0     |
+                * | Blip         | blip.tv              |      No        | 2.9.0     | 4.4.0     |
+                * | Rdio         | rdio.com             |      Yes       | 3.6.0     | 4.4.1     |
+                * | Rdio         | rd.io                |      Yes       | 3.6.0     | 4.4.1     |
+                *
+                * @see wp_oembed_add_provider()
+                *
+                * @since 2.9.0
+                *
+                * @param array $providers An array of popular oEmbed providers.
+                */
+               $this->providers = apply_filters( 'oembed_providers', $providers );
 
                // Fix any embeds that contain new lines in the middle of the HTML which breaks wpautop().
                add_filter( 'oembed_dataparse', array($this, '_strip_newlines'), 10, 3 );
        }
 
        /**
-        * The do-it-all function that takes a URL and attempts to return the HTML.
+        * Exposes private/protected methods for backward compatibility.
+        *
+        * @since 4.0.0
+        * @access public
+        *
+        * @param callable $name      Method to call.
+        * @param array    $arguments Arguments to pass when calling.
+        * @return mixed|bool Return value of the callback, false otherwise.
+        */
+       public function __call( $name, $arguments ) {
+               if ( in_array( $name, $this->compat_methods ) ) {
+                       return call_user_func_array( array( $this, $name ), $arguments );
+               }
+               return false;
+       }
+
+       /**
+        * Takes a URL and returns the corresponding oEmbed provider's URL, if there is one.
+        *
+        * @since 4.0.0
+        * @access public
         *
         * @see WP_oEmbed::discover()
-        * @see WP_oEmbed::fetch()
-        * @see WP_oEmbed::data2html()
         *
-        * @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.
-        * @return bool|string False on failure, otherwise the UNSANITIZED (and potentially unsafe) HTML that should be used to embed.
+        * @param string        $url  The URL to the content.
+        * @param string|array  $args Optional provider arguments.
+        * @return false|string False on failure, otherwise the oEmbed provider URL.
         */
-       function get_html( $url, $args = '' ) {
+       public function get_provider( $url, $args = '' ) {
+               $args = wp_parse_args( $args );
+
                $provider = false;
 
                if ( !isset($args['discover']) )
@@ -97,33 +246,167 @@ class WP_oEmbed {
                if ( !$provider && $args['discover'] )
                        $provider = $this->discover( $url );
 
-               if ( !$provider || false === $data = $this->fetch( $provider, $url, $args ) )
+               return $provider;
+       }
+
+       /**
+        * Adds an oEmbed provider.
+        *
+        * The provider is removed just-in-time when wp_oembed_add_provider() is called before
+        * the {@see 'plugins_loaded'} hook.
+        *
+        * The just-in-time addition is for the benefit of the {@see 'oembed_providers'} filter.
+        *
+        * @static
+        * @since 4.0.0
+        * @access public
+        *
+        * @see wp_oembed_add_provider()
+        *
+        * @param string $format   Format of URL that this provider can handle. You can use
+        *                         asterisks as wildcards.
+        * @param string $provider The URL to the oEmbed provider..
+        * @param bool   $regex    Optional. Whether the $format parameter is in a regex format.
+        *                         Default false.
+        */
+       public static function _add_provider_early( $format, $provider, $regex = false ) {
+               if ( empty( self::$early_providers['add'] ) ) {
+                       self::$early_providers['add'] = array();
+               }
+
+               self::$early_providers['add'][ $format ] = array( $provider, $regex );
+       }
+
+       /**
+        * Removes an oEmbed provider.
+        *
+        * The provider is removed just-in-time when wp_oembed_remove_provider() is called before
+        * the {@see 'plugins_loaded'} hook.
+        *
+        * The just-in-time removal is for the benefit of the {@see 'oembed_providers'} filter.
+        *
+        * @since 4.0.0
+        * @access public
+        * @static
+        *
+        * @see wp_oembed_remove_provider()
+        *
+        * @param string $format The format of URL that this provider can handle. You can use
+        *                       asterisks as wildcards.
+        */
+       public static function _remove_provider_early( $format ) {
+               if ( empty( self::$early_providers['remove'] ) ) {
+                       self::$early_providers['remove'] = array();
+               }
+
+               self::$early_providers['remove'][] = $format;
+       }
+
+       /**
+        * The do-it-all function that takes a URL and attempts to return the HTML.
+        *
+        * @see WP_oEmbed::fetch()
+        * @see WP_oEmbed::data2html()
+        *
+        * @since 2.9.0
+        * @access public
+        *
+        * @param string       $url  The URL to the content that should be attempted to be embedded.
+        * @param array|string $args Optional. Arguments, usually passed from a shortcode. Default empty.
+        * @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 = '' ) {
+               $args = wp_parse_args( $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 ) ) {
                        return false;
+               }
 
+               /**
+                * Filters the HTML returned by the oEmbed provider.
+                *
+                * @since 2.9.0
+                *
+                * @param string $data The returned oEmbed HTML.
+                * @param string $url  URL of the content to be embedded.
+                * @param array  $args Optional arguments, usually passed from a shortcode.
+                */
                return apply_filters( 'oembed_result', $this->data2html( $data, $url ), $url, $args );
        }
 
        /**
-        * Attempts to find oEmbed provider discovery <link> tags at the given URL.
+        * Attempts to discover link tags at the given URL for an oEmbed provider.
         *
-        * @param string $url The URL that should be inspected for discovery <link> tags.
-        * @return bool|string False on failure, otherwise the oEmbed provider URL.
+        * @since 2.9.0
+        * @access public
+        *
+        * @param string $url The URL that should be inspected for discovery `<link>` tags.
+        * @return false|string False on failure, otherwise the oEmbed provider URL.
         */
-       function discover( $url ) {
+       public function discover( $url ) {
                $providers = array();
+               $args = array(
+                       'limit_response_size' => 153600, // 150 KB
+               );
+
+               /**
+                * Filters oEmbed remote get arguments.
+                *
+                * @since 4.0.0
+                *
+                * @see WP_Http::request()
+                *
+                * @param array  $args oEmbed remote get arguments.
+                * @param string $url  URL to be inspected.
+                */
+               $args = apply_filters( 'oembed_remote_get_args', $args, $url );
 
                // Fetch URL content
-               if ( $html = wp_remote_retrieve_body( wp_safe_remote_get( $url ) ) ) {
-
-                       // <link> types that contain oEmbed provider URLs
+               $request = wp_safe_remote_get( $url, $args );
+               if ( $html = wp_remote_retrieve_body( $request ) ) {
+
+                       /**
+                        * Filters the link types that contain oEmbed provider URLs.
+                        *
+                        * @since 2.9.0
+                        *
+                        * @param array $format Array of oEmbed link types. Accepts 'application/json+oembed',
+                        *                      'text/xml+oembed', and 'application/xml+oembed' (incorrect,
+                        *                      used by at least Vimeo).
+                        */
                        $linktypes = apply_filters( 'oembed_linktypes', array(
                                'application/json+oembed' => 'json',
                                'text/xml+oembed' => 'xml',
-                               'application/xml+oembed' => 'xml', // Incorrect, but used by at least Vimeo
+                               'application/xml+oembed' => 'xml',
                        ) );
 
                        // Strip <body>
-                       $html = substr( $html, 0, stripos( $html, '</head>' ) );
+                       if ( $html_head_end = stripos( $html, '</head>' ) ) {
+                               $html = substr( $html, 0, $html_head_end );
+                       }
 
                        // Do a quick check
                        $tagfound = false;
@@ -134,12 +417,12 @@ class WP_oEmbed {
                                }
                        }
 
-                       if ( $tagfound && preg_match_all( '/<link([^<>]+)>/i', $html, $links ) ) {
+                       if ( $tagfound && preg_match_all( '#<link([^<>]+)/?>#iU', $html, $links ) ) {
                                foreach ( $links[1] as $link ) {
                                        $atts = shortcode_parse_atts( $link );
 
                                        if ( !empty($atts['type']) && !empty($linktypes[$atts['type']]) && !empty($atts['href']) ) {
-                                               $providers[$linktypes[$atts['type']]] = $atts['href'];
+                                               $providers[$linktypes[$atts['type']]] = htmlspecialchars_decode( $atts['href'] );
 
                                                // Stop here if it's JSON (that's all we need)
                                                if ( 'json' == $linktypes[$atts['type']] )
@@ -161,21 +444,33 @@ class WP_oEmbed {
        /**
         * Connects to a oEmbed provider and returns the result.
         *
-        * @param string $provider The URL to the oEmbed provider.
-        * @param string $url The URL to the content that is desired to be embedded.
-        * @param array $args Optional arguments. Usually passed from a shortcode.
-        * @return bool|object False on failure, otherwise the result in the form of an object.
+        * @since 2.9.0
+        * @access public
+        *
+        * @param string       $provider The URL to the oEmbed provider.
+        * @param string       $url      The URL to the content that is desired to be embedded.
+        * @param array|string $args     Optional. Arguments, usually passed from a shortcode. Default empty.
+        * @return false|object False on failure, otherwise the result in the form of an object.
         */
-       function fetch( $provider, $url, $args = '' ) {
-               $args = wp_parse_args( $args, wp_embed_defaults() );
+       public function fetch( $provider, $url, $args = '' ) {
+               $args = wp_parse_args( $args, wp_embed_defaults( $url ) );
 
                $provider = add_query_arg( 'maxwidth', (int) $args['width'], $provider );
                $provider = add_query_arg( 'maxheight', (int) $args['height'], $provider );
                $provider = add_query_arg( 'url', urlencode($url), $provider );
 
+               /**
+                * Filters the oEmbed URL to be fetched.
+                *
+                * @since 2.9.0
+                *
+                * @param string $provider URL of the oEmbed provider.
+                * @param string $url      URL of the content to be embedded.
+                * @param array  $args     Optional arguments, usually passed from a shortcode.
+                */
                $provider = apply_filters( 'oembed_fetch_url', $provider, $url, $args );
 
-               foreach( array( 'json', 'xml' ) as $format ) {
+               foreach ( array( 'json', 'xml' ) as $format ) {
                        $result = $this->_fetch_with_format( $provider, $format );
                        if ( is_wp_error( $result ) && 'not-implemented' == $result->get_error_code() )
                                continue;
@@ -189,13 +484,18 @@ class WP_oEmbed {
         *
         * @since 3.0.0
         * @access private
+        *
         * @param string $provider_url_with_args URL to the provider with full arguments list (url, maxheight, etc.)
         * @param string $format Format to use
-        * @return bool|object False on failure, otherwise the result in the form of an object.
+        * @return false|object|WP_Error False on failure, otherwise the result in the form of an object.
         */
-       function _fetch_with_format( $provider_url_with_args, $format ) {
+       private function _fetch_with_format( $provider_url_with_args, $format ) {
                $provider_url_with_args = add_query_arg( 'format', $format, $provider_url_with_args );
-               $response = wp_safe_remote_get( $provider_url_with_args );
+
+               /** This filter is documented in wp-includes/class-oembed.php */
+               $args = apply_filters( 'oembed_remote_get_args', array(), $provider_url_with_args );
+
+               $response = wp_safe_remote_get( $provider_url_with_args, $args );
                if ( 501 == wp_remote_retrieve_response_code( $response ) )
                        return new WP_Error( 'not-implemented' );
                if ( ! $body = wp_remote_retrieve_body( $response ) )
@@ -209,9 +509,13 @@ class WP_oEmbed {
         *
         * @since 3.0.0
         * @access private
+        *
+        * @param string $response_body
+        * @return object|false
         */
-       function _parse_json( $response_body ) {
-               return ( ( $data = json_decode( trim( $response_body ) ) ) && is_object( $data ) ) ? $data : false;
+       private function _parse_json( $response_body ) {
+               $data = json_decode( trim( $response_body ) );
+               return ( $data && is_object( $data ) ) ? $data : false;
        }
 
        /**
@@ -219,8 +523,11 @@ class WP_oEmbed {
         *
         * @since 3.0.0
         * @access private
+        *
+        * @param string $response_body
+        * @return object|false
         */
-       function _parse_xml( $response_body ) {
+       private function _parse_xml( $response_body ) {
                if ( ! function_exists( 'libxml_disable_entity_loader' ) )
                        return false;
 
@@ -236,13 +543,16 @@ class WP_oEmbed {
        }
 
        /**
-        * Helper function for parsing an XML response body.
+        * Serves as a helper function for parsing an XML response body.
         *
         * @since 3.6.0
         * @access private
+        *
+        * @param string $response_body
+        * @return object|false
         */
        private function _parse_xml_body( $response_body ) {
-               if ( ! function_exists( 'simplexml_import_dom' ) || ! class_exists( 'DOMDocument' ) )
+               if ( ! function_exists( 'simplexml_import_dom' ) || ! class_exists( 'DOMDocument', false ) )
                        return false;
 
                $dom = new DOMDocument;
@@ -271,13 +581,16 @@ class WP_oEmbed {
        }
 
        /**
-        * Converts a data object from {@link WP_oEmbed::fetch()} and returns the HTML.
+        * Converts a data object from WP_oEmbed::fetch() and returns the HTML.
+        *
+        * @since 2.9.0
+        * @access public
         *
         * @param object $data A data object result from an oEmbed provider.
         * @param string $url The URL to the content that is desired to be embedded.
-        * @return bool|string False on error, otherwise the HTML needed to embed.
+        * @return false|string False on error, otherwise the HTML needed to embed.
         */
-       function data2html( $data, $url ) {
+       public function data2html( $data, $url ) {
                if ( ! is_object( $data ) || empty( $data->type ) )
                        return false;
 
@@ -309,43 +622,77 @@ class WP_oEmbed {
                                $return = false;
                }
 
-               // You can use this filter to add support for custom data types or to filter the result
+               /**
+                * Filters the returned oEmbed HTML.
+                *
+                * Use this filter to add support for custom data types, or to filter the result.
+                *
+                * @since 2.9.0
+                *
+                * @param string $return The returned oEmbed HTML.
+                * @param object $data   A data object result from an oEmbed provider.
+                * @param string $url    The URL of the content to be embedded.
+                */
                return apply_filters( 'oembed_dataparse', $return, $data, $url );
        }
 
        /**
-        * Strip any new lines from the HTML.
+        * Strips any new lines from the HTML.
+        *
+        * @since 2.9.0 as strip_scribd_newlines()
+        * @since 3.0.0
+        * @access public
         *
-        * @access private
         * @param string $html Existing HTML.
         * @param object $data Data object from WP_oEmbed::data2html()
         * @param string $url The original URL passed to oEmbed.
         * @return string Possibly modified $html
         */
-       function _strip_newlines( $html, $data, $url ) {
-               if ( false !== strpos( $html, "\n" ) )
-                       $html = str_replace( array( "\r\n", "\n" ), '', $html );
+       public function _strip_newlines( $html, $data, $url ) {
+               if ( false === strpos( $html, "\n" ) ) {
+                       return $html;
+               }
+
+               $count = 1;
+               $found = array();
+               $token = '__PRE__';
+               $search = array( "\t", "\n", "\r", ' ' );
+               $replace = array( '__TAB__', '__NL__', '__CR__', '__SPACE__' );
+               $tokenized = str_replace( $search, $replace, $html );
+
+               preg_match_all( '#(<pre[^>]*>.+?</pre>)#i', $tokenized, $matches, PREG_SET_ORDER );
+               foreach ( $matches as $i => $match ) {
+                       $tag_html = str_replace( $replace, $search, $match[0] );
+                       $tag_token = $token . $i;
 
-               return $html;
+                       $found[ $tag_token ] = $tag_html;
+                       $html = str_replace( $tag_html, $tag_token, $html, $count );
+               }
+
+               $replaced = str_replace( $replace, $search, $html );
+               $stripped = str_replace( array( "\r\n", "\n" ), '', $replaced );
+               $pre = array_values( $found );
+               $tokens = array_keys( $found );
+
+               return str_replace( $tokens, $pre, $stripped );
        }
 }
 
 /**
- * Returns the initialized {@link WP_oEmbed} object
+ * Returns the initialized WP_oEmbed object.
  *
  * @since 2.9.0
  * @access private
  *
- * @see WP_oEmbed
- * @uses WP_oEmbed
+ * @staticvar WP_oEmbed $wp_oembed
  *
  * @return WP_oEmbed object.
  */
 function _wp_oembed_get_object() {
-       static $wp_oembed;
+       static $wp_oembed = null;
 
-       if ( is_null($wp_oembed) )
+       if ( is_null( $wp_oembed ) ) {
                $wp_oembed = new WP_oEmbed();
-
+       }
        return $wp_oembed;
 }