Viewing file:  class-twitter.php (11.93 KB) -rw-rw-rw-
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<?php
/**
* @package WPSEO\Frontend
*/
/**
* This class handles the Twitter card functionality.
*
* @link https://dev.twitter.com/docs/cards
*/
class WPSEO_Twitter {
/**
* @var object Instance of this class
*/
public static $instance;
/**
* @var array Images
*/
private $images = array();
/**
* @var array Images
*/
public $shown_images = array();
/**
* @var array $options Holds the options for the Twitter Card functionality
*/
public $options;
/**
* Will hold the Twitter card type being created
*
* @var string
*/
private $type;
/**
* Class constructor
*/
public function __construct() {
$this->options = WPSEO_Options::get_all();
$this->twitter();
}
/**
* Outputs the Twitter Card code on singular pages.
*/
public function twitter() {
wp_reset_query();
$this->type();
$this->description();
$this->title();
$this->site_twitter();
$this->site_domain();
$this->image();
if ( is_singular() ) {
$this->author();
}
/**
* Action: 'wpseo_twitter' - Hook to add all WP SEO Twitter output to so they're close together.
*/
do_action( 'wpseo_twitter' );
}
/**
* Display the Twitter card type.
*
* This defaults to summary but can be filtered using the <code>wpseo_twitter_card_type</code> filter.
*
* @link https://dev.twitter.com/docs/cards
*/
protected function type() {
$this->determine_card_type();
$this->sanitize_card_type();
$this->output_metatag( 'card', $this->type );
}
/**
* Determines the twitter card type for the current page
*/
private function determine_card_type() {
$this->type = $this->options['twitter_card_type'];
if ( is_singular() ) {
// If the current post has a gallery, output a gallery card
if ( has_shortcode( $GLOBALS['post']->post_content, 'gallery' ) ) {
$this->images = get_post_gallery_images();
if ( count( $this->images ) > 3 ) {
$this->type = 'gallery';
}
}
}
/**
* Filter: 'wpseo_twitter_card_type' - Allow changing the Twitter Card type as output in the Twitter card by WP SEO
*
* @api string $unsigned The type string
*/
$this->type = apply_filters( 'wpseo_twitter_card_type', $this->type );
}
/**
* Determines whether the card type is of a type currently allowed by Twitter
*
* @link https://dev.twitter.com/cards/types
*/
private function sanitize_card_type() {
if ( ! in_array( $this->type, array(
'summary',
'summary_large_image',
'photo',
'gallery',
'app',
'player',
'product',
) )
) {
$this->type = 'summary';
}
}
/**
* Output the metatag
*
* @param string $name
* @param string $value
* @param bool $escaped
*/
private function output_metatag( $name, $value, $escaped = false ) {
// Escape the value if not escaped
if ( false === $escaped ) {
$value = esc_attr( $value );
}
/**
* Filter: 'wpseo_twitter_metatag_key' - Make the Twitter metatag key filterable
*
* @api string $key The Twitter metatag key
*/
$metatag_key = apply_filters( 'wpseo_twitter_metatag_key', 'name' );
// Output meta
echo '<meta ', esc_attr( $metatag_key ), '="twitter:', esc_attr( $name ), '" content="', $value, '"/>', "\n";
}
/**
* Displays the description for Twitter.
*
* Only used when OpenGraph is inactive.
*/
protected function description() {
if ( is_singular() ) {
$meta_desc = $this->single_description();
}
elseif ( WPSEO_Frontend::get_instance()->is_posts_page() ) {
$meta_desc = $this->single_description( get_option( 'page_for_posts' ) );
}
else {
$meta_desc = $this->fallback_description();
}
/**
* Filter: 'wpseo_twitter_description' - Allow changing the Twitter description as output in the Twitter card by WP SEO
*
* @api string $twitter The description string
*/
$meta_desc = apply_filters( 'wpseo_twitter_description', $meta_desc );
if ( is_string( $meta_desc ) && $meta_desc !== '' ) {
$this->output_metatag( 'description', $meta_desc );
}
}
/**
* Returns the description for a singular page
*
* @param int $post_id
*
* @return string
*/
private function single_description( $post_id = 0 ) {
$meta_desc = trim( WPSEO_Meta::get_value( 'twitter-description', $post_id ) );
if ( is_string( $meta_desc ) && '' !== $meta_desc ) {
return $meta_desc;
}
$meta_desc = $this->fallback_description();
if ( is_string( $meta_desc ) && '' !== $meta_desc ) {
return $meta_desc;
}
return strip_tags( get_the_excerpt() );
}
/**
* Returns a fallback description
*
* @return string
*/
private function fallback_description() {
return trim( WPSEO_Frontend::get_instance()->metadesc( false ) );
}
/**
* Displays the title for Twitter.
*
* Only used when OpenGraph is inactive.
*/
protected function title() {
if ( is_singular() ) {
$title = $this->single_title();
}
elseif ( WPSEO_Frontend::get_instance()->is_posts_page() ) {
$title = $this->single_title( get_option( 'page_for_posts' ) );
}
else {
$title = $this->fallback_title();
}
/**
* Filter: 'wpseo_twitter_title' - Allow changing the Twitter title as output in the Twitter card by WP SEO
*
* @api string $twitter The title string
*/
$title = apply_filters( 'wpseo_twitter_title', $title );
if ( is_string( $title ) && $title !== '' ) {
$this->output_metatag( 'title', $title );
}
}
/**
* Returns the Twitter title for a single post
*
* @param int $post_id
*
* @return string
*/
private function single_title( $post_id = 0 ) {
$title = WPSEO_Meta::get_value( 'twitter-title', $post_id );
if ( ! is_string( $title ) || '' === $title ) {
return $this->fallback_title();
}
else {
return $title;
}
}
/**
* Returns the Twitter title for any page
*
* @return string
*/
private function fallback_title() {
return WPSEO_Frontend::get_instance()->title( '' );
}
/**
* Displays the Twitter account for the site.
*/
protected function site_twitter() {
/**
* Filter: 'wpseo_twitter_site' - Allow changing the Twitter site account as output in the Twitter card by WP SEO
*
* @api string $unsigned Twitter site account string
*/
$site = apply_filters( 'wpseo_twitter_site', $this->options['twitter_site'] );
$site = $this->get_twitter_id( $site );
if ( is_string( $site ) && $site !== '' ) {
$this->output_metatag( 'site', '@' . $site );
}
}
/**
* Checks if the given id is actually an id or a url and if url, distills the id from it.
*
* Solves issues with filters returning urls and theme's/other plugins also adding a user meta
* twitter field which expects url rather than an id (which is what we expect).
*
* @param string $id Twitter id or url
*
* @return string|bool Twitter id or false if it failed to get a valid twitter id
*/
private function get_twitter_id( $id ) {
if ( preg_match( '`([A-Za-z0-9_]{1,25})$`', $id, $match ) ) {
return $match[1];
}
else {
return false;
}
}
/**
* Displays the domain tag for the site.
*/
protected function site_domain() {
/**
* Filter: 'wpseo_twitter_domain' - Allow changing the Twitter domain as output in the Twitter card by WP SEO
*
* @api string $unsigned Name string
*/
$domain = apply_filters( 'wpseo_twitter_domain', get_bloginfo( 'name' ) );
if ( is_string( $domain ) && $domain !== '' ) {
$this->output_metatag( 'domain', $domain );
}
}
/**
* Displays the image for Twitter
*
* Only used when OpenGraph is inactive or Summary Large Image card is chosen.
*/
protected function image() {
if ( 'gallery' === $this->type ) {
$this->gallery_images_output();
}
else {
$this->single_image_output();
}
if ( count( $this->shown_images ) == 0 && $this->options['og_default_image'] !== '' ) {
$this->image_output( $this->options['og_default_image'] );
}
}
/**
* Outputs the first 4 images of a gallery as the posts gallery images
*/
private function gallery_images_output() {
$image_counter = 0;
foreach ( $this->images as $image ) {
if ( $image_counter > 3 ) {
return;
}
$this->image_output( $image, 'image' . $image_counter );
$image_counter ++;
}
}
/**
* Takes care of image output when we only need to display a single image.
*/
private function single_image_output() {
if ( $this->homepage_image_output() ) {
return;
}
if ( is_singular() ) {
if ( $this->image_from_meta_values_output() ) {
return;
}
if ( $this->image_thumbnail_output() ) {
return;
}
if ( $this->image_from_content_output() ) {
return;
}
}
}
/**
* Show the front page image
*
* @return bool
*/
private function homepage_image_output() {
if ( is_front_page() ) {
if ( $this->options['og_frontpage_image'] !== '' ) {
$this->image_output( $this->options['og_frontpage_image'] );
return true;
}
}
return false;
}
/**
* Outputs a Twitter image tag for a given image
*
* @param string $img The source URL to the image.
* @param string $tag The tag to output, defaults to <code>image:src</code> but can be altered for use in galleries.
*
* @return bool
*/
protected function image_output( $img, $tag = 'image:src' ) {
/**
* Filter: 'wpseo_twitter_image' - Allow changing the Twitter Card image
*
* @api string $img Image URL string
*/
$img = apply_filters( 'wpseo_twitter_image', $img );
$escaped_img = esc_url( $img );
if ( in_array( $escaped_img, $this->shown_images ) ) {
return false;
}
if ( is_string( $escaped_img ) && $escaped_img !== '' ) {
$this->output_metatag( $tag, $escaped_img, true );
array_push( $this->shown_images, $escaped_img );
return true;
}
return false;
}
/**
* Retrieve images from the post meta values
*
* @return bool
*/
private function image_from_meta_values_output() {
foreach ( array( 'twitter-image', 'opengraph-image' ) as $tag ) {
$img = WPSEO_Meta::get_value( $tag );
if ( $img !== '' ) {
$this->image_output( $img );
return true;
}
}
return false;
}
/**
* Retrieve the featured image
*
* @return bool
*/
private function image_thumbnail_output() {
if ( function_exists( 'has_post_thumbnail' ) && has_post_thumbnail( get_the_ID() ) ) {
/**
* Filter: 'wpseo_twitter_image_size' - Allow changing the Twitter Card image size
*
* @api string $featured_img Image size string
*/
$featured_img = wp_get_attachment_image_src( get_post_thumbnail_id( get_the_ID() ), apply_filters( 'wpseo_twitter_image_size', 'full' ) );
if ( $featured_img ) {
$this->image_output( $featured_img[0] );
return true;
}
}
return false;
}
/**
* Retrieve the image from the content
*
* @return bool
*/
private function image_from_content_output() {
if ( preg_match_all( '`<img [^>]+>`', $GLOBALS['post']->post_content, $matches ) ) {
foreach ( $matches[0] as $img ) {
if ( preg_match( '`src=(["\'])(.*?)\1`', $img, $match ) ) {
$this->image_output( $match[2] );
return true;
}
}
}
return false;
}
/**
* Displays the authors Twitter account.
*/
protected function author() {
$twitter = ltrim( trim( get_the_author_meta( 'twitter', get_post()->post_author ) ), '@' );
/**
* Filter: 'wpseo_twitter_creator_account' - Allow changing the Twitter account as output in the Twitter card by WP SEO
*
* @api string $twitter The twitter account name string
*/
$twitter = apply_filters( 'wpseo_twitter_creator_account', $twitter );
$twitter = $this->get_twitter_id( $twitter );
if ( is_string( $twitter ) && $twitter !== '' ) {
$this->output_metatag( 'creator', '@' . $twitter );
}
elseif ( $this->options['twitter_site'] !== '' ) {
if ( is_string( $this->options['twitter_site'] ) && $this->options['twitter_site'] !== '' ) {
$this->output_metatag( 'creator', '@' . $this->options['twitter_site'] );
}
}
}
/**
* Get the singleton instance of this class
*
* @return object
*/
public static function get_instance() {
if ( ! ( self::$instance instanceof self ) ) {
self::$instance = new self();
}
return self::$instance;
}
} /* End of class */
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