升级WordPress的核心。

原型

update_core( string $from, string $to )

描述

这将在WordPress目录的基础上创建一个.maintenance文件,以确保在将文件复制到其位置时,人们无法访问该网站。

参数

$from (string) (Required) 新版解压缩路径。

$to (string) (Required) 旧WordPress安装的路径。

返回值

(WP_Error|null)  

源文件

路径:wp-admin/includes/update-core.php

<?php
...
function update_core($from, $to) {
	global $wp_filesystem, $_old_files, $_new_bundled_files, $wpdb;
	@set_time_limit( 300 );
	/**
	 * Filters feedback messages displayed during the core update process.
	 *
	 * The filter is first evaluated after the zip file for the latest version
	 * has been downloaded and unzipped. It is evaluated five more times during
	 * the process:
	 *
	 * 1. Before WordPress begins the core upgrade process.
	 * 2. Before Maintenance Mode is enabled.
	 * 3. Before WordPress begins copying over the necessary files.
	 * 4. Before Maintenance Mode is disabled.
	 * 5. Before the database is upgraded.
	 *
	 * @since 2.5.0
	 *
	 * @param string $feedback The core update feedback messages.
	 */
	apply_filters( 'update_feedback', __( 'Verifying the unpacked files&#8230;' ) );
	// Sanity check the unzipped distribution.
	$distro = '';
	$roots = array( '/wordpress/', '/wordpress-mu/' );
	foreach ( $roots as $root ) {
		if ( $wp_filesystem->exists( $from . $root . 'readme.html' ) && $wp_filesystem->exists( $from . $root . 'wp-includes/version.php' ) ) {
			$distro = $root;
			break;
		}
	}
	if ( ! $distro ) {
		$wp_filesystem->delete( $from, true );
		return new WP_Error( 'insane_distro', __('The update could not be unpacked') );
	}
	/*
	 * Import $wp_version, $required_php_version, and $required_mysql_version from the new version.
	 * DO NOT globalise any variables imported from `version-current.php` in this function.
	 *
	 * BC Note: $wp_filesystem->wp_content_dir() returned unslashed pre-2.8
	 */
	$versions_file = trailingslashit( $wp_filesystem->wp_content_dir() ) . 'upgrade/version-current.php';
	if ( ! $wp_filesystem->copy( $from . $distro . 'wp-includes/version.php', $versions_file ) ) {
		$wp_filesystem->delete( $from, true );
		return new WP_Error( 'copy_failed_for_version_file', __( 'The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.' ), 'wp-includes/version.php' );
	}
	$wp_filesystem->chmod( $versions_file, FS_CHMOD_FILE );
	require( WP_CONTENT_DIR . '/upgrade/version-current.php' );
	$wp_filesystem->delete( $versions_file );
	$php_version    = phpversion();
	$mysql_version  = $wpdb->db_version();
	$old_wp_version = $GLOBALS['wp_version']; // The version of WordPress we're updating from
	$development_build = ( false !== strpos( $old_wp_version . $wp_version, '-' )  ); // a dash in the version indicates a Development release
	$php_compat     = version_compare( $php_version, $required_php_version, '>=' );
	if ( file_exists( WP_CONTENT_DIR . '/db.php' ) && empty( $wpdb->is_mysql ) )
		$mysql_compat = true;
	else
		$mysql_compat = version_compare( $mysql_version, $required_mysql_version, '>=' );
	if ( !$mysql_compat || !$php_compat )
		$wp_filesystem->delete($from, true);
	if ( !$mysql_compat && !$php_compat )
		return new WP_Error( 'php_mysql_not_compatible', sprintf( __('The update cannot be installed because WordPress %1$s requires PHP version %2$s or higher and MySQL version %3$s or higher. You are running PHP version %4$s and MySQL version %5$s.'), $wp_version, $required_php_version, $required_mysql_version, $php_version, $mysql_version ) );
	elseif ( !$php_compat )
		return new WP_Error( 'php_not_compatible', sprintf( __('The update cannot be installed because WordPress %1$s requires PHP version %2$s or higher. You are running version %3$s.'), $wp_version, $required_php_version, $php_version ) );
	elseif ( !$mysql_compat )
		return new WP_Error( 'mysql_not_compatible', sprintf( __('The update cannot be installed because WordPress %1$s requires MySQL version %2$s or higher. You are running version %3$s.'), $wp_version, $required_mysql_version, $mysql_version ) );
	/** This filter is documented in wp-admin/includes/update-core.php */
	apply_filters( 'update_feedback', __( 'Preparing to install the latest version&#8230;' ) );
	// Don't copy wp-content, we'll deal with that below
	// We also copy version.php last so failed updates report their old version
	$skip = array( 'wp-content', 'wp-includes/version.php' );
	$check_is_writable = array();
	// Check to see which files don't really need updating - only available for 3.7 and higher
	if ( function_exists( 'get_core_checksums' ) ) {
		// Find the local version of the working directory
		$working_dir_local = WP_CONTENT_DIR . '/upgrade/' . basename( $from ) . $distro;
		$checksums = get_core_checksums( $wp_version, isset( $wp_local_package ) ? $wp_local_package : 'en_US' );
		if ( is_array( $checksums ) && isset( $checksums[ $wp_version ] ) )
			$checksums = $checksums[ $wp_version ]; // Compat code for 3.7-beta2
		if ( is_array( $checksums ) ) {
			foreach ( $checksums as $file => $checksum ) {
				if ( 'wp-content' == substr( $file, 0, 10 ) )
					continue;
				if ( ! file_exists( ABSPATH . $file ) )
					continue;
				if ( ! file_exists( $working_dir_local . $file ) )
					continue;
				if ( '.' === dirname( $file ) && in_array( pathinfo( $file, PATHINFO_EXTENSION ), array( 'html', 'txt' ) ) )
					continue;
				if ( md5_file( ABSPATH . $file ) === $checksum )
					$skip[] = $file;
				else
					$check_is_writable[ $file ] = ABSPATH . $file;
			}
		}
	}
	// If we're using the direct method, we can predict write failures that are due to permissions.
	if ( $check_is_writable && 'direct' === $wp_filesystem->method ) {
		$files_writable = array_filter( $check_is_writable, array( $wp_filesystem, 'is_writable' ) );
		if ( $files_writable !== $check_is_writable ) {
			$files_not_writable = array_diff_key( $check_is_writable, $files_writable );
			foreach ( $files_not_writable as $relative_file_not_writable => $file_not_writable ) {
				// If the writable check failed, chmod file to 0644 and try again, same as copy_dir().
				$wp_filesystem->chmod( $file_not_writable, FS_CHMOD_FILE );
				if ( $wp_filesystem->is_writable( $file_not_writable ) )
					unset( $files_not_writable[ $relative_file_not_writable ] );
			}
			// Store package-relative paths (the key) of non-writable files in the WP_Error object.
			$error_data = version_compare( $old_wp_version, '3.7-beta2', '>' ) ? array_keys( $files_not_writable ) : '';
			if ( $files_not_writable )
				return new WP_Error( 'files_not_writable', __( 'The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.' ), implode( ', ', $error_data ) );
		}
	}
	/** This filter is documented in wp-admin/includes/update-core.php */
	apply_filters( 'update_feedback', __( 'Enabling Maintenance mode&#8230;' ) );
	// Create maintenance file to signal that we are upgrading
	$maintenance_string = '<?php $upgrading = ' . time() . '; ?>';
	$maintenance_file = $to . '.maintenance';
	$wp_filesystem->delete($maintenance_file);
	$wp_filesystem->put_contents($maintenance_file, $maintenance_string, FS_CHMOD_FILE);
	/** This filter is documented in wp-admin/includes/update-core.php */
	apply_filters( 'update_feedback', __( 'Copying the required files&#8230;' ) );
	// Copy new versions of WP files into place.
	$result = _copy_dir( $from . $distro, $to, $skip );
	if ( is_wp_error( $result ) )
		$result = new WP_Error( $result->get_error_code(), $result->get_error_message(), substr( $result->get_error_data(), strlen( $to ) ) );
	// Since we know the core files have copied over, we can now copy the version file
	if ( ! is_wp_error( $result ) ) {
		if ( ! $wp_filesystem->copy( $from . $distro . 'wp-includes/version.php', $to . 'wp-includes/version.php', true /* overwrite */ ) ) {
			$wp_filesystem->delete( $from, true );
			$result = new WP_Error( 'copy_failed_for_version_file', __( 'The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.' ), 'wp-includes/version.php' );
		}
		$wp_filesystem->chmod( $to . 'wp-includes/version.php', FS_CHMOD_FILE );
	}
	// Check to make sure everything copied correctly, ignoring the contents of wp-content
	$skip = array( 'wp-content' );
	$failed = array();
	if ( isset( $checksums ) && is_array( $checksums ) ) {
		foreach ( $checksums as $file => $checksum ) {
			if ( 'wp-content' == substr( $file, 0, 10 ) )
				continue;
			if ( ! file_exists( $working_dir_local . $file ) )
				continue;
			if ( '.' === dirname( $file ) && in_array( pathinfo( $file, PATHINFO_EXTENSION ), array( 'html', 'txt' ) ) ) {
				$skip[] = $file;
				continue;
			}
			if ( file_exists( ABSPATH . $file ) && md5_file( ABSPATH . $file ) == $checksum )
				$skip[] = $file;
			else
				$failed[] = $file;
		}
	}
	// Some files didn't copy properly
	if ( ! empty( $failed ) ) {
		$total_size = 0;
		foreach ( $failed as $file ) {
			if ( file_exists( $working_dir_local . $file ) )
				$total_size += filesize( $working_dir_local . $file );
		}
		// If we don't have enough free space, it isn't worth trying again.
		// Unlikely to be hit due to the check in unzip_file().
		$available_space = @disk_free_space( ABSPATH );
		if ( $available_space && $total_size >= $available_space ) {
			$result = new WP_Error( 'disk_full', __( 'There is not enough free disk space to complete the update.' ) );
		} else {
			$result = _copy_dir( $from . $distro, $to, $skip );
			if ( is_wp_error( $result ) )
				$result = new WP_Error( $result->get_error_code() . '_retry', $result->get_error_message(), substr( $result->get_error_data(), strlen( $to ) ) );
		}
	}
	// Custom Content Directory needs updating now.
	// Copy Languages
	if ( !is_wp_error($result) && $wp_filesystem->is_dir($from . $distro . 'wp-content/languages') ) {
		if ( WP_LANG_DIR != ABSPATH . WPINC . '/languages' || @is_dir(WP_LANG_DIR) )
			$lang_dir = WP_LANG_DIR;
		else
			$lang_dir = WP_CONTENT_DIR . '/languages';
		if ( [email protected]is_dir($lang_dir) && 0 === strpos($lang_dir, ABSPATH) ) { // Check the language directory exists first
			$wp_filesystem->mkdir($to . str_replace(ABSPATH, '', $lang_dir), FS_CHMOD_DIR); // If it's within the ABSPATH we can handle it here, otherwise they're out of luck.
			clearstatcache(); // for FTP, Need to clear the stat cache
		}
		if ( @is_dir($lang_dir) ) {
			$wp_lang_dir = $wp_filesystem->find_folder($lang_dir);
			if ( $wp_lang_dir ) {
				$result = copy_dir($from . $distro . 'wp-content/languages/', $wp_lang_dir);
				if ( is_wp_error( $result ) )
					$result = new WP_Error( $result->get_error_code() . '_languages', $result->get_error_message(), substr( $result->get_error_data(), strlen( $wp_lang_dir ) ) );
			}
		}
	}
	/** This filter is documented in wp-admin/includes/update-core.php */
	apply_filters( 'update_feedback', __( 'Disabling Maintenance mode&#8230;' ) );
	// Remove maintenance file, we're done with potential site-breaking changes
	$wp_filesystem->delete( $maintenance_file );
	// 3.5 -> 3.5+ - an empty twentytwelve directory was created upon upgrade to 3.5 for some users, preventing installation of Twenty Twelve.
	if ( '3.5' == $old_wp_version ) {
		if ( is_dir( WP_CONTENT_DIR . '/themes/twentytwelve' ) && ! file_exists( WP_CONTENT_DIR . '/themes/twentytwelve/style.css' )  ) {
			$wp_filesystem->delete( $wp_filesystem->wp_themes_dir() . 'twentytwelve/' );
		}
	}
	// Copy New bundled plugins & themes
	// This gives us the ability to install new plugins & themes bundled with future versions of WordPress whilst avoiding the re-install upon upgrade issue.
	// $development_build controls us overwriting bundled themes and plugins when a non-stable release is being updated
	if ( !is_wp_error($result) && ( ! defined('CORE_UPGRADE_SKIP_NEW_BUNDLED') || ! CORE_UPGRADE_SKIP_NEW_BUNDLED ) ) {
		foreach ( (array) $_new_bundled_files as $file => $introduced_version ) {
			// If a $development_build or if $introduced version is greater than what the site was previously running
			if ( $development_build || version_compare( $introduced_version, $old_wp_version, '>' ) ) {
				$directory = ('/' == $file[ strlen($file)-1 ]);
				list($type, $filename) = explode('/', $file, 2);
				// Check to see if the bundled items exist before attempting to copy them
				if ( ! $wp_filesystem->exists( $from . $distro . 'wp-content/' . $file ) )
					continue;
				if ( 'plugins' == $type )
					$dest = $wp_filesystem->wp_plugins_dir();
				elseif ( 'themes' == $type )
					$dest = trailingslashit($wp_filesystem->wp_themes_dir()); // Back-compat, ::wp_themes_dir() did not return trailingslash'd pre-3.2
				else
					continue;
				if ( ! $directory ) {
					if ( ! $development_build && $wp_filesystem->exists( $dest . $filename ) )
						continue;
					if ( ! $wp_filesystem->copy($from . $distro . 'wp-content/' . $file, $dest . $filename, FS_CHMOD_FILE) )
						$result = new WP_Error( "copy_failed_for_new_bundled_$type", __( 'Could not copy file.' ), $dest . $filename );
				} else {
					if ( ! $development_build && $wp_filesystem->is_dir( $dest . $filename ) )
						continue;
					$wp_filesystem->mkdir($dest . $filename, FS_CHMOD_DIR);
					$_result = copy_dir( $from . $distro . 'wp-content/' . $file, $dest . $filename);
					// If a error occurs partway through this final step, keep the error flowing through, but keep process going.
					if ( is_wp_error( $_result ) ) {
						if ( ! is_wp_error( $result ) )
							$result = new WP_Error;
						$result->add( $_result->get_error_code() . "_$type", $_result->get_error_message(), substr( $_result->get_error_data(), strlen( $dest ) ) );
					}
				}
			}
		} //end foreach
	}
	// Handle $result error from the above blocks
	if ( is_wp_error($result) ) {
		$wp_filesystem->delete($from, true);
		return $result;
	}
	// Remove old files
	foreach ( $_old_files as $old_file ) {
		$old_file = $to . $old_file;
		if ( !$wp_filesystem->exists($old_file) )
			continue;
		// If the file isn't deleted, try writing an empty string to the file instead.
		if ( ! $wp_filesystem->delete( $old_file, true ) && $wp_filesystem->is_file( $old_file ) ) {
			$wp_filesystem->put_contents( $old_file, '' );
		}
	}
	// Remove any Genericons example.html's from the filesystem
	_upgrade_422_remove_genericons();
	// Remove the REST API plugin if its version is Beta 4 or lower
	_upgrade_440_force_deactivate_incompatible_plugins();
	// Upgrade DB with separate request
	/** This filter is documented in wp-admin/includes/update-core.php */
	apply_filters( 'update_feedback', __( 'Upgrading database&#8230;' ) );
	$db_upgrade_url = admin_url('upgrade.php?step=upgrade_db');
	wp_remote_post($db_upgrade_url, array('timeout' => 60));
	// Clear the cache to prevent an update_option() from saving a stale db_version to the cache
	wp_cache_flush();
	// (Not all cache back ends listen to 'flush')
	wp_cache_delete( 'alloptions', 'options' );
	// Remove working directory
	$wp_filesystem->delete($from, true);
	// Force refresh of update information
	if ( function_exists('delete_site_transient') )
		delete_site_transient('update_core');
	else
		delete_option('update_core');
	/**
	 * Fires after WordPress core has been successfully updated.
	 *
	 * @since 3.3.0
	 *
	 * @param string $wp_version The current WordPress version.
	 */
	do_action( '_core_updated_successfully', $wp_version );
	// Clear the option that blocks auto updates after failures, now that we've been successful.
	if ( function_exists( 'delete_site_option' ) )
		delete_site_option( 'auto_core_update_failed' );
	return $wp_version;
}
...
?>

其他

英文文档:https://developer.wordpress.org/reference/functions/update_core/