the_content хук-фильтр . WP 1.2.1

Используется для фильтрации контента записи, после того как контент получен из базы данных, но до того как он будет выведет на экран.

Использование

add_filter( 'the_content', 'filter_function_name_11' );
function filter_function_name_11( $content ) {
	// Фильтр...

	return $content;
}

$content(строка)

Строка, которую нужно отфильтровать и вернуть обратно.

Примеры

#1 Демонстрация работы

Для демонстрации работы фильтра, добавим в конец каждого текста поста надпись " Конец!":

add_filter('the_content', 'the_end');
function the_end( $text ){
	return $text . ' Конец!';
}

#2 Фильтр контента отдельной страницы

Этот пример можно использовать, для создания постоянной страницы контент которой будет генерироваться в зависимости от чего-либо, допустим переменной $_GET запроса (например для указанyого автора ?the_author=crank):

add_filter( 'the_content', 'my_the_content_filter' );
function my_the_content_filter( $content ){
	// Если не страница debug ничего не делаем
	if( $GLOBALS['post']->post_name != 'debug' )
		return $content;

	// Выполняем действия
	// предполагается что в УРЛ указана переменная запроса the_author
	return "Это страница автора: ". $_GET['the_author'];
}

#3 Иконка поста

Этот пример добавит картинку перед постом (смотрите is_single()). Подразумевается, что картинки называется post_icon.png и находится в папке image в каталоге темы. Фильтр работает в пониженном приоритете 20 (обычно 10), это значит что он будет обработан позднее остальных.

add_filter( 'the_content', 'my_the_content_filter', 20 );
function my_the_content_filter( $content ){
	if ( is_single() )
		// Добавляем картинку в начало каждой страницы
		$content = sprintf(
			'<img class="post-icon" src="%s/images/post_icon.png" alt="Post icon" title=""/>%s',
			get_bloginfo( 'stylesheet_directory' ),
			$content
		);

	// Возвращаем контент.
	return $content;
}

#4 Миниатюра поста в начале

Этот пример показывает, как добавить миниатюру поста перед выводом контента. Миниатюра поста устанавливается при редактировании поста (эта функция должна быть включена, смотрите add_theme_support()). Миниатюра будет добавлена только к постам (записям типа post):

add_filter( 'the_content', 'featured_image_before_content' ); 
function featured_image_before_content( $content ) {
	if ( is_singular('post') && has_post_thumbnail()) {
		$thumbnail = get_the_post_thumbnail();

		$content = $thumbnail . $content;
	}

	return $content;
}

Где используется хук

Код хука-фильтра the_content

...
 * @since 0.71
 *
 * @param string $more_link_text Optional. Content for when there is more text.
 * @param bool   $strip_teaser   Optional. Strip teaser content before the more text. Default is false.
 */
function the_content( $more_link_text = null, $strip_teaser = false) {
	$content = get_the_content( $more_link_text, $strip_teaser );

	/**
	 * Filters the post content.
	 *
	 * @since 0.71
	 *
	 * @param string $content Content of the current post.
	 */
	$content = apply_filters( 'the_content', $content );
	$content = str_replace( ']]>', ']]>', $content );
	echo $content;
}

/**
 * Retrieve the post content.
 *
 * @since 0.71
 *
 * @global int   $page      Page number of a single post/page.
 * @global int   $more      Boolean indicator for whether single post/page is being viewed.
 * @global bool  $preview   Whether post/page is in preview mode.
 * @global array $pages     Array of all pages in post/page. Each array element contains part of the content separated by the <!--nextpage--> tag.
 * @global int   $multipage Boolean indicator for whether multiple pages are in play.
 *
...

...
	global $wpdb;
	$post = get_post( $post_id );
	if ( ! $post ) {
		return false;
	}

	$to_ping = get_to_ping( $post );
	$pinged  = get_pung( $post );
	if ( empty( $to_ping ) ) {
		$wpdb->update($wpdb->posts, array( 'to_ping' => '' ), array( 'ID' => $post->ID ) );
		return;
	}

	if ( empty($post->post_excerpt) ) {
		/** This filter is documented in wp-includes/post-template.php */
		$excerpt = apply_filters( 'the_content', $post->post_content, $post->ID );
	} else {
		/** This filter is documented in wp-includes/post-template.php */
		$excerpt = apply_filters( 'the_excerpt', $post->post_excerpt );
	}

	$excerpt = str_replace(']]>', ']]>', $excerpt);
	$excerpt = wp_html_excerpt($excerpt, 252, '…');

	/** This filter is documented in wp-includes/post-template.php */
	$post_title = apply_filters( 'the_title', $post->post_title, $post->ID );
	$post_title = strip_tags($post_title);

	if ( $to_ping ) {
		foreach ( (array) $to_ping as $tb_ping ) {
			$tb_ping = trim($tb_ping);
...

...

/**
 * Retrieve the post content for feeds.
 *
 * @since 2.9.0
 * @see get_the_content()
 *
 * @param string $feed_type The type of feed. rss2 | atom | rss | rdf
 * @return string The filtered content.
 */
function get_the_content_feed($feed_type = null) {
	if ( !$feed_type )
		$feed_type = get_default_feed();

	/** This filter is documented in wp-includes/post-template.php */
	$content = apply_filters( 'the_content', get_the_content() );
	$content = str_replace(']]>', ']]>', $content);
	/**
	 * Filters the post content for use in feeds.
	 *
	 * @since 2.9.0
	 *
	 * @param string $content   The current post content.
	 * @param string $feed_type Type of feed. Possible values include 'rss2', 'atom'.
	 *                          Default 'rss2'.
	 */
	return apply_filters( 'the_content_feed', $content, $feed_type );
}

/**
 * Display the post content for feeds.
...

...
			);
		}

		if ( in_array( 'title', $fields, true ) ) {
			$data['title'] = array(
				'raw'      => $post->post_title,
				'rendered' => get_the_title( $post->ID ),
			);
		}

		if ( in_array( 'content', $fields, true ) ) {

			$data['content'] = array(
				'raw'      => $post->post_content,
				/** This filter is documented in wp-includes/post-template.php */
				'rendered' => apply_filters( 'the_content', $post->post_content ),
			);
		}

		if ( in_array( 'excerpt', $fields, true ) ) {
			$data['excerpt'] = array(
				'raw'      => $post->post_excerpt,
				'rendered' => $this->prepare_excerpt_response( $post->post_excerpt, $post ),
			);
		}

		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
		$data = $this->add_additional_fields_to_object( $data, $request );
		$data = $this->filter_response_by_context( $data, $context );
		$response = rest_ensure_response( $data );

...

...
	 * @since 4.7.0
	 *
	 * @param WP_Post         $post    Attachment object.
	 * @param WP_REST_Request $request Request object.
	 * @return WP_REST_Response Response object.
	 */
	public function prepare_item_for_response( $post, $request ) {
		$response = parent::prepare_item_for_response( $post, $request );
		$fields   = $this->get_fields_for_response( $request );
		$data     = $response->get_data();

		if ( in_array( 'description', $fields, true ) ) {
			$data['description'] = array(
				'raw'      => $post->post_content,
				/** This filter is documented in wp-includes/post-template.php */
				'rendered' => apply_filters( 'the_content', $post->post_content ),
			);
		}

		if ( in_array( 'caption', $fields, true ) ) {
			/** This filter is documented in wp-includes/post-template.php */
			$caption         = apply_filters( 'the_excerpt', apply_filters( 'get_the_excerpt', $post->post_excerpt, $post ) );
			$data['caption'] = array(
				'raw'      => $post->post_excerpt,
				'rendered' => $caption,
			);
		}

		if ( in_array( 'alt_text', $fields, true ) ) {
			$data['alt_text'] = get_post_meta( $post->ID, '_wp_attachment_image_alt', true );
		}
...

...
		}

		$has_password_filter = false;

		if ( $this->can_access_password_content( $post, $request ) ) {
			// Allow access to the post, permissions already checked before.
			add_filter( 'post_password_required', '__return_false' );

			$has_password_filter = true;
		}

		if ( in_array( 'content', $fields, true ) ) {
			$data['content'] = array(
				'raw'       => $post->post_content,
				/** This filter is documented in wp-includes/post-template.php */
				'rendered'  => post_password_required( $post ) ? '' : apply_filters( 'the_content', $post->post_content ),
				'protected' => (bool) $post->post_password,
			);
		}

		if ( in_array( 'excerpt', $fields, true ) ) {
			/** This filter is documented in wp-includes/post-template.php */
			$excerpt = apply_filters( 'the_excerpt', apply_filters( 'get_the_excerpt', $post->post_excerpt, $post ) );
			$data['excerpt'] = array(
				'raw'       => $post->post_excerpt,
				'rendered'  => post_password_required( $post ) ? '' : $excerpt,
				'protected' => (bool) $post->post_password,
			);
		}

		if ( $has_password_filter ) {
...

...
 * The ' […]' string can be modified by plugins/themes using the {@see 'excerpt_more'} filter
 *
 * @since 1.5.0
 *
 * @param string $text Optional. The excerpt. If set to empty, an excerpt is generated.
 * @return string The excerpt.
 */
function wp_trim_excerpt( $text = '' ) {
	$raw_excerpt = $text;
	if ( '' == $text ) {
		$text = get_the_content('');

		$text = strip_shortcodes( $text );

		/** This filter is documented in wp-includes/post-template.php */
		$text = apply_filters( 'the_content', $text );
		$text = str_replace(']]>', ']]>', $text);

		/**
		 * Filters the number of words in an excerpt.
		 *
		 * @since 2.7.0
		 *
		 * @param int $number The number of words. Default 55.
		 */
		$excerpt_length = apply_filters( 'excerpt_length', 55 );
		/**
		 * Filters the string in the "more" link displayed after a trimmed excerpt.
		 *
		 * @since 2.9.0
		 *
...

...
			'featured'           => $product->is_featured(),
			'visible'            => $product->is_visible(),
			'catalog_visibility' => $product->get_catalog_visibility(),
			'on_sale'            => $product->is_on_sale(),
			'weight'             => $product->get_weight() ? wc_format_decimal( $product->get_weight(), 2 ) : null,
			'dimensions'         => array(
				'length' => $product->get_length(),
				'width'  => $product->get_width(),
				'height' => $product->get_height(),
				'unit'   => get_option( 'woocommerce_dimension_unit' ),
			),
			'shipping_required'  => $product->needs_shipping(),
			'shipping_taxable'   => $product->is_shipping_taxable(),
			'shipping_class'     => $product->get_shipping_class(),
			'shipping_class_id'  => ( 0 !== $product->get_shipping_class_id() ) ? $product->get_shipping_class_id() : null,
			'description'        => apply_filters( 'the_content', $product->get_description() ),
			'short_description'  => apply_filters( 'woocommerce_short_description', $product->get_short_description() ),
			'reviews_allowed'    => $product->get_reviews_allowed(),
			'average_rating'     => wc_format_decimal( $product->get_average_rating(), 2 ),
			'rating_count'       => $product->get_rating_count(),
			'related_ids'        => array_map( 'absint', array_values( wc_get_related_products( $product->get_id() ) ) ),
			'upsell_ids'         => array_map( 'absint', $product->get_upsell_ids() ),
			'cross_sell_ids'     => array_map( 'absint', $product->get_cross_sell_ids() ),
			'categories'         => wc_get_object_terms( $product->get_id(), 'product_cat', 'name' ),
			'tags'               => wc_get_object_terms( $product->get_id(), 'product_tag', 'name' ),
			'images'             => $this->get_images( $product ),
			'featured_src'       => wp_get_attachment_url( get_post_thumbnail_id( $product->get_id() ) ),
			'attributes'         => $this->get_attributes( $product ),
			'downloads'          => $this->get_downloads( $product ),
			'download_limit'     => $product->get_download_limit(),
			'download_expiry'    => $product->get_download_expiry(),
...

...
			'reviews_allowed'    => $product->get_reviews_allowed(),
			'average_rating'     => wc_format_decimal( $product->get_average_rating(), 2 ),
			'rating_count'       => $product->get_rating_count(),
			'related_ids'        => array_map( 'absint', array_values( wc_get_related_products( $product->get_id() ) ) ),
			'upsell_ids'         => array_map( 'absint', $product->get_upsell_ids() ),
			'cross_sell_ids'     => array_map( 'absint', $product->get_cross_sell_ids() ),
			'categories'         => wc_get_object_terms( $product->get_id(), 'product_cat', 'name' ),
			'tags'               => wc_get_object_terms( $product->get_id(), 'product_tag', 'name' ),
			'images'             => $this->get_images( $product ),
			'featured_src'       => wp_get_attachment_url( get_post_thumbnail_id( $product->get_id() ) ),
			'attributes'         => $this->get_attributes( $product ),
			'downloads'          => $this->get_downloads( $product ),
			'download_limit'     => $product->get_download_limit(),
			'download_expiry'    => $product->get_download_expiry(),
			'download_type'      => 'standard',
			'purchase_note'      => apply_filters( 'the_content', $product->get_purchase_note() ),
			'total_sales'        => $product->get_total_sales(),
			'variations'         => array(),
			'parent'             => array(),
		);
	}

	/**
	 * Get an individual variation's data
	 *
	 * @since 2.1
	 * @param WC_Product $product
	 * @return array
	 */
	private function get_variation_data( $product ) {
		$variations = array();
...