WP_Site_Health::get_test_page_cache(): array

Compatibility

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

Return value

array

The test result.

Performance profile

How much work a call to WP_Site_Health::get_test_page_cache() 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

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

88–150

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 238.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• hookthird-party callbacksdo_action()one call below WP_Site_Health::get_test_page_cache()

Further down the call graph this can also reach query, option, 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 · 7 distinct outcomes

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

Uses · 8

• __()Retrieves the translation of $text.
• wp_kses_post()Sanitizes content for allowed HTML tags for post content.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• number_format_i18n()Converts float number to format based on the locale.
• _n()Translates and retrieves the singular or plural form based on the supplied number.
• WP_Site_Health::get_page_cache_headers()Returns a mapping from response headers to an optional callback to verify if page cache is enabled or not.
• WP_Site_Health::get_page_cache_detail()Gets page cache details.
• WP_Site_Health::get_good_response_time_threshold()Gets the threshold below which a response time is considered good.

Source code

View on Trac ↗View on GitHub ↗

2446	public function get_test_page_cache() {2447		$description  = '<p>' . __( 'Page cache enhances the speed and performance of your site by saving and serving static pages instead of calling for a page every time a user visits.' ) . '</p>';2448		$description .= '<p>' . __( 'Page cache is detected by looking for an active page cache plugin as well as making three requests to the homepage and looking for one or more of the following HTTP client caching response headers:' ) . '</p>';2449		$description .= '<code>' . implode( '</code>, <code>', array_keys( $this->get_page_cache_headers() ) ) . '.</code>';2450 2451		$result = array(2452			'badge'       => array(2453				'label' => __( 'Performance' ),2454				'color' => 'blue',2455			),2456			'description' => wp_kses_post( $description ),2457			'test'        => 'page_cache',2458			'status'      => 'good',2459			'label'       => '',2460			'actions'     => sprintf(2461				'<p><a href="%1$s" target="_blank" rel="noreferrer">%2$s<span class="screen-reader-text"> %3$s</span><span aria-hidden="true" class="dashicons dashicons-external"></span></a></p>',2462				__( 'https://developer.wordpress.org/advanced-administration/performance/optimization/#caching' ),2463				__( 'Learn more about page cache' ),2464				/* translators: Hidden accessibility text. */2465				__( '(opens in a new tab)' )2466			),2467		);2468 2469		$page_cache_detail = $this->get_page_cache_detail();2470 2471		if ( is_wp_error( $page_cache_detail ) ) {2472			$result['label']  = __( 'Unable to detect the presence of page cache' );2473			$result['status'] = 'recommended';2474			$error_info       = sprintf(2475			/* translators: 1: Error message, 2: Error code. */2476				__( 'Unable to detect page cache due to possible loopback request problem. Please verify that the loopback request test is passing. Error: %1$s (Code: %2$s)' ),2477				$page_cache_detail->get_error_message(),2478				$page_cache_detail->get_error_code()2479			);2480			$result['description'] = wp_kses_post( "<p>$error_info</p>" ) . $result['description'];2481			return $result;2482		}2483 2484		$result['status'] = $page_cache_detail['status'];2485 2486		switch ( $page_cache_detail['status'] ) {2487			case 'recommended':2488				$result['label'] = __( 'Page cache is not detected but the server response time is OK' );2489				break;2490			case 'good':2491				$result['label'] = __( 'Page cache is detected and the server response time is good' );2492				break;2493			default:2494				if ( empty( $page_cache_detail['headers'] ) && ! $page_cache_detail['advanced_cache_present'] ) {2495					$result['label'] = __( 'Page cache is not detected and the server response time is slow' );2496				} else {2497					$result['label'] = __( 'Page cache is detected but the server response time is still slow' );2498				}2499		}2500 2501		$page_cache_test_summary = array();2502 2503		if ( empty( $page_cache_detail['response_time'] ) ) {2504			$page_cache_test_summary[] = '<span class="dashicons dashicons-dismiss" aria-hidden="true"></span> ' . __( 'Server response time could not be determined. Verify that loopback requests are working.' );2505		} else {2506 2507			$threshold = $this->get_good_response_time_threshold();2508			if ( $page_cache_detail['response_time'] < $threshold ) {2509				$page_cache_test_summary[] = '<span class="dashicons dashicons-yes-alt" aria-hidden="true"></span> ' . sprintf(2510					/* translators: 1: The response time in milliseconds, 2: The recommended threshold in milliseconds. */2511					__( 'Median server response time was %1$s milliseconds. This is less than the recommended %2$s milliseconds threshold.' ),2512					number_format_i18n( $page_cache_detail['response_time'] ),2513					number_format_i18n( $threshold )2514				);2515			} else {2516				$page_cache_test_summary[] = '<span class="dashicons dashicons-warning" aria-hidden="true"></span> ' . sprintf(2517					/* translators: 1: The response time in milliseconds, 2: The recommended threshold in milliseconds. */2518					__( 'Median server response time was %1$s milliseconds. It should be less than the recommended %2$s milliseconds threshold.' ),2519					number_format_i18n( $page_cache_detail['response_time'] ),2520					number_format_i18n( $threshold )2521				);2522			}2523 2524			if ( empty( $page_cache_detail['headers'] ) ) {2525				$page_cache_test_summary[] = '<span class="dashicons dashicons-warning" aria-hidden="true"></span> ' . __( 'No client caching response headers were detected.' );

Changelog

Introduced in 6.1.0. Unchanged from 6.7.7 through 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 7.1.0 tag, from src/wp-admin/includes/class-wp-site-health.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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