This part of the API is used in the Frontend. The number of files is relatively small, but the number of functions is very large. We will review only major functions.
TSFE (historically stands for "TypoScript Frontend") is the main FE class. It is sometimes called "page" object among developers. This class contains methods that determine page ID, parse TypoScript templates, execute templates, process output and cache it. Also, TSFE is responsible for managing FE user object. TSFE is located in the class tslib_fe (exercise: see if you can guess the path to the file name).
Normally, extensions do not call TSFE methods but use some TSFE class attributes. We will describe the most important attributes here:
additionalHeaderDataThis is an array where FE plugins can add HTML tags that should appear between
<head>and</head>on the page. It is a good practice to start withtx_yourextkey_prefix. Do not add inline<script>(<script>tag without src attribute) here!additionalJavaScriptAn array where FE plugins may add inline JavaScript, if necessary. It is a good practice to start with
tx_yourextkey_prefix.configThis is an array. It is the only member with the config key corresponding to the parsed
configobject from the current TypoScript setup. This array contains merged entries fromconfigandpage.config.fe_userAn object of the class,
tslib_feUserAuth, which represents a FE user. Theuserattribute of this class contains a record from thefe_userstable. If FE user is logged in,$GLOBALS['TSFE']->fe_user->user['uid']will be set, andt3lib_div::testIntwill returntruefor it.idThis is the current page ID. It is very often used in FE plugins as
$GLOBALS['TSFE']->id.langThis attribute is the current language code (string value). This is not the same as the ISO language code. It is TYPO3 code to be used with language files. The value
defaultmeans English. A full list of codes can be found intypo3/sysext/setup/mod/locallang.xmlas a set oflang_*entries.pageThis is a record from the
pagestable that corresponds to the current page. If the page is loaded in a nondefault language, this record will have that language applied (all fields like title or navigation title will be taken frompages_language_overlayand applied to this record).pSetupThis is a parsed TypoScript setup for the plugin. This is useful in certain cases. For example, you may want to examine the setup of another plugin. It is a parsed TypoScript array.
registerThis is an array of registers (see
LOAD_REGISTERin TSRef). FE plugins can set registers, and they will be available to other objects on the page (plugins or TypoScript objects from TypoScript setup). The key is register name, value is register value.rootLineThis is an array of records from the
pagestable that represents the path to the current page from the root of the website.sys_language_contentThis is a
uidfield value for the record in thesys_languagetable. TYPO3 will select content from thett_contenttable withsys_language_uidthat matches this value.sys_language_uidThis is a
uidfield value for the record in thesys_languagetable. It corresponds toconfig.sys_language_uidin TypoScript setup.sys_language_mode
Content objects display information on the page. All content object types are described in TSRef and they are implemented by the class named tslib_cObj, which is located in typo3/sysext/cms/tslib/class.tslib_content.php. A quick look at this class reveals familiar names such as TEXT, HTML, USER, or stdWrap.
This class is used very often in FE plugins. It has lots of very well-documented methods. We will describe many of them in due course when we have to use them in our real extension.
Last but not the least in its importance is the tslib_pibase class. This is a base class for the FE plugins. While it is not mandatory to use it, most plugins do because this class provides many helpful methods. We will discuss this class in detail in Chapter 5 of the book. For now, we should know that this class provides the following function groups:
Link generation
These functions allow plugins to create links with plugin parameters in them.
Handling of localized labels
These functions help to retrieve translated labels from the language files.
Frontend editing
These functions help to add FE editing capabilities to plugins (rarely used by plugins).
Database queries
These functions do specialized database queries. Most of them are equivalents of the
t3lib_DBfunctions.Flexform handling functions
Flexform is a TYPO3 way of having forms inside forms. They are often used for plugin configuration. These functions initialize flexform data and extract information from flexforms.