wp_update_themes

wp_update_themes是一個更新所有安裝在WordPress站點上的主題的函式: 該函式檢查WordPress主題庫的更新，並在必要時應用它們: 該函式用於確保網站上安裝的所有主題都是最新的，並具有最新的安全修復和功能。

根據WordPress.org上託管的最新版本，檢查主題的可用更新。

儘管它的名字是這樣的，這個功能實際上並不執行任何更新，它只是檢查可用的更新。

一個已安裝的所有主題的列表會被髮送到WP，同時還有網站的定位。

檢查位於api.wordpress.org的WordPress伺服器。只有在WordPress沒有安裝的情況下才會檢查。

function wp_update_themes( $extra_stats = array() ) {
	if ( wp_installing() ) {
		return;
	}

	// Include an unmodified $wp_version.
	require ABSPATH . WPINC . '/version.php';

	$installed_themes = wp_get_themes();
	$translations     = wp_get_installed_translations( 'themes' );

	$last_update = get_site_transient( 'update_themes' );

	if ( ! is_object( $last_update ) ) {
		$last_update = new stdClass;
	}

	$themes  = array();
	$checked = array();
	$request = array();

	// Put slug of active theme into request.
	$request['active'] = get_option( 'stylesheet' );

	foreach ( $installed_themes as $theme ) {
		$checked[ $theme->get_stylesheet() ] = $theme->get( 'Version' );

		$themes[ $theme->get_stylesheet() ] = array(
			'Name'       => $theme->get( 'Name' ),
			'Title'      => $theme->get( 'Name' ),
			'Version'    => $theme->get( 'Version' ),
			'Author'     => $theme->get( 'Author' ),
			'Author URI' => $theme->get( 'AuthorURI' ),
			'UpdateURI'  => $theme->get( 'UpdateURI' ),
			'Template'   => $theme->get_template(),
			'Stylesheet' => $theme->get_stylesheet(),
		);
	}

	$doing_cron = wp_doing_cron();

	// Check for update on a different schedule, depending on the page.
	switch ( current_filter() ) {
		case 'upgrader_process_complete':
			$timeout = 0;
			break;
		case 'load-update-core.php':
			$timeout = MINUTE_IN_SECONDS;
			break;
		case 'load-themes.php':
		case 'load-update.php':
			$timeout = HOUR_IN_SECONDS;
			break;
		default:
			if ( $doing_cron ) {
				$timeout = 2 * HOUR_IN_SECONDS;
			} else {
				$timeout = 12 * HOUR_IN_SECONDS;
			}
	}

	$time_not_changed = isset( $last_update->last_checked ) && $timeout > ( time() - $last_update->last_checked );

	if ( $time_not_changed && ! $extra_stats ) {
		$theme_changed = false;

		foreach ( $checked as $slug => $v ) {
			if ( ! isset( $last_update->checked[ $slug ] ) || (string) $last_update->checked[ $slug ] !== (string) $v ) {
				$theme_changed = true;
			}
		}

		if ( isset( $last_update->response ) && is_array( $last_update->response ) ) {
			foreach ( $last_update->response as $slug => $update_details ) {
				if ( ! isset( $checked[ $slug ] ) ) {
					$theme_changed = true;
					break;
				}
			}
		}

		// Bail if we've checked recently and if nothing has changed.
		if ( ! $theme_changed ) {
			return;
		}
	}

	// Update last_checked for current to prevent multiple blocking requests if request hangs.
	$last_update->last_checked = time();
	set_site_transient( 'update_themes', $last_update );

	$request['themes'] = $themes;

	$locales = array_values( get_available_languages() );

	/**
	 * Filters the locales requested for theme translations.
	 *
	 * @since 3.7.0
	 * @since 4.5.0 The default value of the `$locales` parameter changed to include all locales.
	 *
	 * @param string[] $locales Theme locales. Default is all available locales of the site.
	 */
	$locales = apply_filters( 'themes_update_check_locales', $locales );
	$locales = array_unique( $locales );

	if ( $doing_cron ) {
		$timeout = 30; // 30 seconds.
	} else {
		// Three seconds, plus one extra second for every 10 themes.
		$timeout = 3 + (int) ( count( $themes ) / 10 );
	}

	$options = array(
		'timeout'    => $timeout,
		'body'       => array(
			'themes'       => wp_json_encode( $request ),
			'translations' => wp_json_encode( $translations ),
			'locale'       => wp_json_encode( $locales ),
		),
		'user-agent' => 'WordPress/' . $wp_version . '; ' . home_url( '/' ),
	);

	if ( $extra_stats ) {
		$options['body']['update_stats'] = wp_json_encode( $extra_stats );
	}

	$url      = 'http://api.wordpress.org/themes/update-check/1.1/';
	$http_url = $url;
	$ssl      = wp_http_supports( array( 'ssl' ) );

	if ( $ssl ) {
		$url = set_url_scheme( $url, 'https' );
	}

	$raw_response = wp_remote_post( $url, $options );

	if ( $ssl && is_wp_error( $raw_response ) ) {
		trigger_error(
			sprintf(
				/* translators: %s: Support forums URL. */
				__( 'An unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration. If you continue to have problems, please try the <a href="%s">support forums</a>.' ),
				__( 'https://wordpress.org/support/forums/' )
			) . ' ' . __( '(WordPress could not establish a secure connection to WordPress.org. Please contact your server administrator.)' ),
			headers_sent() || WP_DEBUG ? E_USER_WARNING : E_USER_NOTICE
		);
		$raw_response = wp_remote_post( $http_url, $options );
	}

	if ( is_wp_error( $raw_response ) || 200 !== wp_remote_retrieve_response_code( $raw_response ) ) {
		return;
	}

	$new_update               = new stdClass;
	$new_update->last_checked = time();
	$new_update->checked      = $checked;

	$response = json_decode( wp_remote_retrieve_body( $raw_response ), true );

	if ( is_array( $response ) ) {
		$new_update->response     = $response['themes'];
		$new_update->no_update    = $response['no_update'];
		$new_update->translations = $response['translations'];
	}

	// Support updates for any themes using the `Update URI` header field.
	foreach ( $themes as $theme_stylesheet => $theme_data ) {
		if ( ! $theme_data['UpdateURI'] || isset( $new_update->response[ $theme_stylesheet ] ) ) {
			continue;
		}

		$hostname = wp_parse_url( esc_url_raw( $theme_data['UpdateURI'] ), PHP_URL_HOST );

		/**
		 * Filters the update response for a given theme hostname.
		 *
		 * The dynamic portion of the hook name, `$hostname`, refers to the hostname
		 * of the URI specified in the `Update URI` header field.
		 *
		 * @since 6.1.0
		 *
		 * @param array|false $update {
		 *     The theme update data with the latest details. Default false.
		 *
		 *     @type string $id           Optional. ID of the theme for update purposes, should be a URI
		 *                                specified in the `Update URI` header field.
		 *     @type string $theme        Directory name of the theme.
		 *     @type string $version      The version of the theme.
		 *     @type string $url          The URL for details of the theme.
		 *     @type string $package      Optional. The update ZIP for the theme.
		 *     @type string $tested       Optional. The version of WordPress the theme is tested against.
		 *     @type string $requires_php Optional. The version of PHP which the theme requires.
		 *     @type bool   $autoupdate   Optional. Whether the theme should automatically update.
		 *     @type array  $translations {
		 *         Optional. List of translation updates for the theme.
		 *
		 *         @type string $language   The language the translation update is for.
		 *         @type string $version    The version of the theme this translation is for.
		 *                                  This is not the version of the language file.
		 *         @type string $updated    The update timestamp of the translation file.
		 *                                  Should be a date in the `YYYY-MM-DD HH:MM:SS` format.
		 *         @type string $package    The ZIP location containing the translation update.
		 *         @type string $autoupdate Whether the translation should be automatically installed.
		 *     }
		 * }
		 * @param array       $theme_data       Theme headers.
		 * @param string      $theme_stylesheet Theme stylesheet.
		 * @param string[]    $locales          Installed locales to look up translations for.
		 */
		$update = apply_filters( "update_themes_{$hostname}", false, $theme_data, $theme_stylesheet, $locales );

		if ( ! $update ) {
			continue;
		}

		$update = (object) $update;

		// Is it valid? We require at least a version.
		if ( ! isset( $update->version ) ) {
			continue;
		}

		// This should remain constant.
		$update->id = $theme_data['UpdateURI'];

		// WordPress needs the version field specified as 'new_version'.
		if ( ! isset( $update->new_version ) ) {
			$update->new_version = $update->version;
		}

		// Handle any translation updates.
		if ( ! empty( $update->translations ) ) {
			foreach ( $update->translations as $translation ) {
				if ( isset( $translation['language'], $translation['package'] ) ) {
					$translation['type'] = 'theme';
					$translation['slug'] = isset( $update->theme ) ? $update->theme : $update->id;

					$new_update->translations[] = $translation;
				}
			}
		}

		unset( $new_update->no_update[ $theme_stylesheet ], $new_update->response[ $theme_stylesheet ] );

		if ( version_compare( $update->new_version, $theme_data['Version'], '>' ) ) {
			$new_update->response[ $theme_stylesheet ] = (array) $update;
		} else {
			$new_update->no_update[ $theme_stylesheet ] = (array) $update;
		}
	}

	set_site_transient( 'update_themes', $new_update );
}