返回一个文章、页面、附件或网站的短链接。

这个函数的存在是为了提供一个所有主题和插件都可以针对的短链接标签。一个插件必须挂钩以提供实际的短链接。默认的短链接支持只限于为文章提供?p=风格的链接。插件可以通过{@see ‘pre_get_shortlink’}过滤器短路这个函数，或者通过{@see ‘get_shortlink’}过滤器过滤输出。

function wp_get_shortlink( $id = 0, $context = 'post', $allow_slugs = true ) {
	/**
	 * Filters whether to preempt generating a shortlink for the given post.
	 *
	 * Returning a value other than false from the filter will short-circuit
	 * the shortlink generation process, returning that value instead.
	 *
	 * @since 3.0.0
	 *
	 * @param false|string $return      Short-circuit return value. Either false or a URL string.
	 * @param int          $id          Post ID, or 0 for the current post.
	 * @param string       $context     The context for the link. One of 'post' or 'query',
	 * @param bool         $allow_slugs Whether to allow post slugs in the shortlink.
	 */
	$shortlink = apply_filters( 'pre_get_shortlink', false, $id, $context, $allow_slugs );

	if ( false !== $shortlink ) {
		return $shortlink;
	}

	$post_id = 0;
	if ( 'query' === $context && is_singular() ) {
		$post_id = get_queried_object_id();
		$post    = get_post( $post_id );
	} elseif ( 'post' === $context ) {
		$post = get_post( $id );
		if ( ! empty( $post->ID ) ) {
			$post_id = $post->ID;
		}
	}

	$shortlink = '';

	// Return `?p=` link for all public post types.
	if ( ! empty( $post_id ) ) {
		$post_type = get_post_type_object( $post->post_type );

		if ( 'page' === $post->post_type && get_option( 'page_on_front' ) == $post->ID && 'page' === get_option( 'show_on_front' ) ) {
			$shortlink = home_url( '/' );
		} elseif ( $post_type && $post_type->public ) {
			$shortlink = home_url( '?p=' . $post_id );
		}
	}

	/**
	 * Filters the shortlink for a post.
	 *
	 * @since 3.0.0
	 *
	 * @param string $shortlink   Shortlink URL.
	 * @param int    $id          Post ID, or 0 for the current post.
	 * @param string $context     The context for the link. One of 'post' or 'query',
	 * @param bool   $allow_slugs Whether to allow post slugs in the shortlink. Not used by default.
	 */
	return apply_filters( 'get_shortlink', $shortlink, $id, $context, $allow_slugs );
}