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PHP

<?php
/* Twitter Cards
*
* Hooks onto the Open Graph protocol and extends it by adding only the tags
* we need for twitter cards.
*
* @see /wp-content/blog-plugins/open-graph.php
* @see https://dev.twitter.com/docs/cards
*/
function wpcom_twitter_cards_tags( $og_tags ) {
global $post;
if( post_password_required() )
return $og_tags;
if ( apply_filters( 'jetpack_disable_twitter_cards', false ) )
return $og_tags;
/*
* These tags apply to any page (home, archives, etc)
*/
$og_tags['twitter:site'] = ( defined('IS_WPCOM') && IS_WPCOM ) ? '@wordpressdotcom' : '@jetpack';
if ( ! is_singular() || ! empty( $og_tags['twitter:card'] ) )
return $og_tags;
/*
* The following tags only apply to single pages.
*/
$card_type = 'summary';
// Try to give priority to featured images
if ( class_exists('Jetpack_PostImages') ) {
$featured = Jetpack_PostImages::from_thumbnail( $post->ID, 240, 240 );
if ( !empty( $featured ) && count( $featured ) > 0 ) {
if ( (int) $featured[0]['src_width'] >= 280 && (int) $featured[0]['src_height'] >= 150 ) {
$card_type = 'summary_large_image';
$og_tags['twitter:image:src'] = add_query_arg( 'w', 640, $featured[0]['src'] );
} else {
$og_tags['twitter:image'] = add_query_arg( 'w', 240, $featured[0]['src'] );
}
}
}
// Only proceed with media analysis if a featured image has not superseded it already.
if ( empty( $og_tags['twitter:image'] ) && empty( $og_tags['twitter:image:src'] ) ) {
if ( ! class_exists( 'Jetpack_Media_Summary' ) && defined('IS_WPCOM') && IS_WPCOM )
include WP_CONTENT_DIR . '/lib/class.wpcom-media-summary.php';
// Test again, class should already be auto-loaded in Jetpack.
// If not, skip extra media analysis and stick with a summary card
if ( class_exists( 'Jetpack_Media_Summary' ) ) {
$extract = Jetpack_Media_Summary::get( $post->ID );
if ( 'gallery' == $extract['type'] ) {
list( $og_tags, $card_type ) = wpcom_twitter_cards_define_type_based_on_image_count( $og_tags, $extract );
} else if ( 'video' == $extract['type'] ) {
// Leave as summary, but with large pict of poster frame (we know those comply to Twitter's size requirements)
$card_type = 'summary_large_image';
$og_tags['twitter:image:src'] = add_query_arg( 'w', 640, $extract['image'] );
} else {
list( $og_tags, $card_type ) = wpcom_twitter_cards_define_type_based_on_image_count( $og_tags, $extract );
}
}
}
$og_tags['twitter:card'] = $card_type;
// If we have information on the author/creator, then include that as well
if ( ! empty( $post ) && ! empty( $post->post_author ) ) {
$handle = apply_filters( 'jetpack_sharing_twitter_via', '', $post->ID );
if ( !empty( $handle ) && 'wordpressdotcom' != $handle )
$og_tags['twitter:creator'] = '@' . $handle;
}
// Make sure we have a description for Twitter, their validator isn't happy without some content (single space not valid).
if ( ! isset( $og_tags['og:description'] ) || '' == trim( $og_tags['og:description'] ) ) { // empty( trim( $og_tags['og:description'] ) ) isn't valid php
$has_creator = ( !empty($og_tags['twitter:creator']) && '@wordpressdotcom' != $og_tags['twitter:creator'] ) ? true : false;
if ( 'photo' == $card_type )
$og_tags['twitter:description'] = ( $has_creator ) ? sprintf( __('Photo post by %s.', 'jetpack'), $og_tags['twitter:creator'] ) : __('Photo post.', 'jetpack');
else if ( !empty( $extract ) && 'video' == $extract['type'] ) // use $extract['type'] since $card_type is 'summary' for video posts
$og_tags['twitter:description'] = ( $has_creator ) ? sprintf( __('Video post by %s.', 'jetpack'), $og_tags['twitter:creator'] ) : __('Video post.', 'jetpack');
else if ( 'gallery' == $card_type )
$og_tags['twitter:description'] = ( $has_creator ) ? sprintf( __('Gallery post by %s.', 'jetpack'), $og_tags['twitter:creator'] ) : __('Gallery post.', 'jetpack');
else
$og_tags['twitter:description'] = ( $has_creator ) ? sprintf( __('New post by %s.', 'jetpack'), $og_tags['twitter:creator'] ) : __('New post.', 'jetpack');
}
return $og_tags;
}
function wpcom_twitter_cards_define_type_based_on_image_count( $og_tags, $extract ) {
$card_type = 'summary';
$img_count = $extract['count']['image'];
if ( empty( $img_count ) ) {
// No images, use Blavatar as a thumbnail for the summary type.
if ( function_exists('blavatar_domain') ) {
$blavatar_domain = blavatar_domain(site_url());
if ( blavatar_exists( $blavatar_domain ) )
$og_tags['twitter:image'] = blavatar_url( $blavatar_domain, 'img', 240);
}
// Not falling back on Gravatar, because there's no way to know if we end up with an auto-generated one.
} else if ( 1 == $img_count && ( 'image' == $extract['type'] || 'gallery' == $extract['type'] ) ) {
// 1 image = photo
// Test for $extract['type'] to limit to image and gallery, so we don't send a potential fallback image like a Gravatar as a photo post.
$card_type = 'photo';
$og_tags['twitter:image'] = add_query_arg( 'w', 1400, ( empty( $extract['images'] ) ) ? $extract['image'] : $extract['images'][0]['url'] );
} else if ( $img_count <= 3 ) {
// 2-3 images = summary with small thumbnail
$og_tags['twitter:image'] = add_query_arg( 'w', 240, ( empty( $extract['images'] ) ) ? $extract['image'] : $extract['images'][0]['url'] );
} else if ( $img_count >= 4 ) {
// >= 4 images = gallery
$card_type = 'gallery';
$og_tags = wpcom_twitter_cards_gallery( $extract, $og_tags );
}
return array( $og_tags, $card_type );
}
function wpcom_twitter_cards_gallery( $extract, $og_tags ) {
foreach( $extract['images'] as $key => $value ) {
if ( $key > 3 )
break; // Can only send a max of 4 picts (https://dev.twitter.com/docs/cards/types/gallery-card)
$og_tags[ 'twitter:image' . $key ] = add_query_arg( 'w', 640, $value['url'] );
}
return $og_tags;
}
add_filter( 'jetpack_open_graph_tags', 'wpcom_twitter_cards_tags' );
function wpcom_twitter_cards_output( $og_tag ) {
return ( false !== strpos( $og_tag, 'twitter:' ) ) ? preg_replace( '/property="([^"]+)"/', 'name="\1"', $og_tag ) : $og_tag;
}
add_filter( 'jetpack_open_graph_output', 'wpcom_twitter_cards_output' );