best practice for using core base functions (CRM_Utils_System_Base) from an extension?

Question

CRM_Utils_System_Base defines a great set of key functions that look like they should work in any system.

What is the correct way to access this functionality within an extension?

FYI these are the classes public methods:

addHTMLHead($head) addScript($code, $region) addScriptUrl($url, $region) addStyle($code, $region) addStyleUrl($url, $region) appendBreadCrumb($breadCrumbs) appendCoreResources(&$list) authenticate($name, $password, $loadCMSBootstrap = FALSE, $realPath = NULL) checkPermissionAddUser() clearResourceCache() cmsRootPath() createUser(&$params, $mail) flush() getBestUFID($user = NULL) getBestUFUniqueIdentifier($user = NULL) getDefaultBlockLocation() getDefaultSiteSettings($dir) getLoggedInUfID() getLoggedInUniqueIdentifier() getLoginDestination(&$form) getModules() getTimeZoneOffset() getTimeZoneString() getUFLocale() getUfId($username) getUniqueIdentifierFromUserObject($user) getUser($contactID) getUserIDFromUserObject($user) getUserRecordUrl($contactID) getVersion() isUserLoggedIn() languageNegotiationURL( loadUser($user) logger($message) logout() mapConfigToSSL() outputError($content) permissionDenied() postURL($action) resetBreadCrumb() setMessage($message) setMySQLTimeZone() setTitle($title, $pageTitle = NULL) setUserSession($data) theme(&$content, $print = FALSE, $maintenance = FALSE) updateCMSName($ufID, $email) updateCategories() url($path = NULL, $query = NULL, $absolute = FALSE, $fragment = NULL, $htmlize = TRUE, $frontend = FALSE, $forceBackend = FALSE) userLoginFinalize($params = array())

(note a few of these are marked as only be called in certain contexts)

Answer 1

This base class is not intended to be used by itself, but extended based on the CMS. CiviCRM will automatically give you an instance of the correct object which extends this base class. You can access it via the CRM_Utils_System static methods. For example:

CRM_Utils_System::appendBreadCrumb($something);

or

CRM_Utils_System::isUserLoggedIn();

Answer 2

It's probably easier to answer based on a specific need rather than your more generic "hey, found a stash of toys, can I play with them? ;)"

They are a few that you shouldn't use directly but use the more specific functions, so instead of:

addHTMLHead($head)
addScript($code, $region)
addScriptUrl($url, $region)
addStyle($code, $region)
addStyleUrl($url, $region)

it's more common/recommended to use CRM_Core_Resources

CRM_Core_Resources::singleton()
->addScriptFile(...)
->addStyleFile(...)
...

Answer 3

There is this example: CRM/Utils/System.php-1503- /** CRM/Utils/System.php-1504- * Check if user is logged in. CRM/Utils/System.php-1505- * CRM/Utils/System.php-1506- * @return bool CRM/Utils/System.php-1507- */ CRM/Utils/System.php:1508: public static function isUserLoggedIn() { CRM/Utils/System.php-1509- $config = CRM_Core_Config::singleton(); CRM/Utils/System.php:1510: return $config->userSystem->isUserLoggedIn(); CRM/Utils/System.php-1511- }