pingback( string $content, int|WP_Post $post ): array<string,

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$contentstring

Post content to check for links. If empty will retrieve from post.

$postint|WP_Post

Post ID or object.

Return value

array<string,

bool> An array of pingback statuses indexed by link.

Performance profile

How much work a call to pingback() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Expensive

Reaches an outbound HTTP request via wp_safe_remote_head().

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

19–52

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 146.

Plugin surface

2 hooks

Third-party callbacks on 'pre_ping', 'pingback_useragent' run inside this call, and their cost is not bounded by anything here.

Called by

1

1 place in core call this, so the cost is paid more often than your own code shows.

What it touches

• querycontent queryget_post()called directly
• hookthird-party callbacksdo_action_ref_array()called directly
• optionoption read or writeget_option()one call below pingback()
• httpoutbound HTTP requestwp_safe_remote_head()one call below pingback()

Further down the call graph this can also reach cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 2 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost pingback() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 2

2 hooks fire while pingback() runs, in this order:

1. 1
   do_action( pre_ping )actionline 3240 (+64 into the body)

   Fires just before pinging back links found in a post.

2. 2
   apply_filters( pingback_useragent )filterline 3269 (+93 into the body)

   Filters the user agent sent when pinging-back a URL.

Uses · 12

• get_post()Retrieves post data given a post ID or post object.
• get_pung()Retrieves URLs already pinged for a post.
• wp_extract_urls()Uses RegEx to extract URLs from arbitrary content.
• url_to_postid()Examines a URL and try to determine the post ID it represents.
• is_local_attachment()Determines whether an attachment URI is local and really an attachment.
• do_action_ref_array()Calls the callback functions that have been added to an action hook, specifying arguments in an array.
• discover_pingback_server_uri()Finds a pingback server URI based on the given URL.
• get_permalink()Retrieves the full permalink for the current post or post ID.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• get_bloginfo()Retrieves information about the current site.
• add_ping()Adds a URL to those already pinged.
• WP_HTTP_IXR_Client::__construct()

Used by · 1

• do_all_pingbacks()Performs all pingbacks.

Source code

View on Trac ↗View on GitHub ↗

3176function pingback( $content, $post ) {3177	require_once ABSPATH . WPINC . '/class-IXR.php';3178	require_once ABSPATH . WPINC . '/class-wp-http-ixr-client.php';3179 3180	// Original code by Mort (http://mort.mine.nu:8080).3181	$post_links = array();3182 3183	$post = get_post( $post );3184 3185	if ( ! $post ) {3186		return array();3187	}3188 3189	$pung = get_pung( $post );3190 3191	if ( empty( $content ) ) {3192		$content = $post->post_content;3193	}3194 3195	/*3196	 * Step 1.3197	 * Parsing the post, external links (if any) are stored in the $post_links array.3198	 */3199	$post_links_temp = wp_extract_urls( $content );3200 3201	$ping_status = array();3202	/*3203	 * Step 2.3204	 * Walking through the links array.3205	 * First we get rid of links pointing to sites, not to specific files.3206	 * Example:3207	 * http://dummy-weblog.org3208	 * http://dummy-weblog.org/3209	 * http://dummy-weblog.org/post.php3210	 * We don't wanna ping first and second types, even if they have a valid <link/>.3211	 */3212	foreach ( (array) $post_links_temp as $link_test ) {3213		// If we haven't pung it already and it isn't a link to itself.3214		if ( ! in_array( $link_test, $pung, true ) && ( url_to_postid( $link_test ) !== $post->ID )3215			// Also, let's never ping local attachments.3216			&& ! is_local_attachment( $link_test )3217		) {3218			$test = parse_url( $link_test );3219			if ( $test ) {3220				if ( isset( $test['query'] ) ) {3221					$post_links[] = $link_test;3222				} elseif ( isset( $test['path'] ) && ( '/' !== $test['path'] ) && ( '' !== $test['path'] ) ) {3223					$post_links[] = $link_test;3224				}3225			}3226		}3227	}3228 3229	$post_links = array_unique( $post_links );3230 3231	/**3232	 * Fires just before pinging back links found in a post.3233	 *3234	 * @since 2.0.03235	 *3236	 * @param string[] $post_links Array of link URLs to be checked (passed by reference).3237	 * @param string[] $pung       Array of link URLs already pinged (passed by reference).3238	 * @param int      $post_id    The post ID.3239	 */3240	do_action_ref_array( 'pre_ping', array( &$post_links, &$pung, $post->ID ) );3241 3242	foreach ( (array) $post_links as $pagelinkedto ) {3243		$pingback_server_url = discover_pingback_server_uri( $pagelinkedto );3244 3245		if ( $pingback_server_url ) {3246			// Allow an additional 60 seconds for each pingback to complete.3247			if ( function_exists( 'set_time_limit' ) ) {3248				set_time_limit( 60 );3249			}3250 3251			// Now, the RPC call.3252			$pagelinkedfrom = get_permalink( $post );3253 3254			// Using a timeout of 3 seconds should be enough to cover slow servers.3255			$client          = new WP_HTTP_IXR_Client( $pingback_server_url );

Changelog

Introduced in 0.71. One change between 6.7.7 and 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.0.4 tag, from src/wp-includes/comment.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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