Core API

3.9.2. Rendering page trees

In your backend modules you might like to show information or perform processing for a part of the page tree. There is a whole family of libraries in the core for making trees from records, static page trees or page trees that can be browsed (open/close nodes).

In this simple example I will show how to get the HTML for a static page tree, using the class "t3lib_pageTree" (child of "t3lib_treeView"). The output will look like this (missing the normal TYPO3 styles though):

 

The PHP code that generates this looks like:

     1: require_once(PATH_t3lib.'class.t3lib_pagetree.php');

     2: 

     3:     // Initialize starting point of page tree:

     4: $treeStartingPoint = 1135;

     5: $treeStartingRecord = t3lib_BEfunc::getRecord('pages', $treeStartingPoint);

     6: $depth = 2;

     7: 

     8:     // Initialize tree object:

     9: $tree = t3lib_div::makeInstance('t3lib_pageTree');

    10: $tree->init('AND '.$GLOBALS['BE_USER']->getPagePermsClause(1));

    11: 

    12:     // Creating top icon; the current page

    13: $HTML = t3lib_iconWorks::getIconImage('pages', $treeStartingRecord, $GLOBALS['BACK_PATH'],'align="top"');

    14: $tree->tree[] = array(

    15:     'row' => $treeStartingRecord,

    16:     'HTML'=>$HTML

    17: );

    18: 

    19:     // Create the tree from starting point:

    20: $tree->getTree($treeStartingPoint, $depth, '');

    21: #debug($tree->tree);

    22: 

    23:     // Put together the tree HTML:

    24: $output = '

    25:     <tr  bgcolor="#999999">

    26:         <td><b>Icon / Title:</b></td>

    27:         <td><b>Page UID:</b></td>

    28:     </tr>';

    29: foreach($tree->tree as $data)    {

    30:     $output.='

    31:         <tr bgcolor="#cccccc">

    32:             <td nowrap="nowrap">'.$data['HTML'].htmlspecialchars($data['row']['title']).'</td>

    33:             <td>'.htmlspecialchars($data['row']['uid']).'</td>

    34:         </tr>';

    35: }

    36: 

    37: $output = '<table border="0" cellspacing="1" cellpadding="0">'.$output.'</table>';

1. In line 1 the class is included.
   Notice how the constant "PATH_t3lib" is used to set the path for "t3lib/".

2. Line 4-5 sets up the starting point. You need a page id for that and additionally you must select that page record.
   Notice how another important API function, t3lib_BEfunc::getRecord(), is used to get the record array for the page!

3. Line 6 defines that the page tree will go 2 levels down from the starting point.

4. Line 9-10 initializes the class.
   Notice how the BE_USER object is called to get an SQL where clause that will ensure that only pages that are accessible for the user will be shown in the tree!
   Notice how t3lib_div::makeInstance() is used to create the object. This is required by the TYPO3 CGL.

5. Line 13-17 sets up the starting point page in the tree. This must be done externally if you would like your tree to include the root page (which is not always the case).
   Notice how line 13 calls the function t3lib_iconWorks::getIconImage() to get the correct icon image for the pages table record! Also, $GLOBALS['BACK_PATH'] is used to make sure the icon has a correct "back-path" to the location where the icon is on the server.

6. Line 20 renders the page tree from the starting point and $depth levels down (at least 1 level)

7. The rendered page tree is stored in a data array inside of the tree object. We need to traverse the tree data to create the tree in HTML. This gives us the chance to organize the tree in a table for instance. That is very useful if you need to show additional information for each page.

   1. Lines 24-28 renders a table row with headings for the tree.

   2. Lines 29-35 traverses the tree data and for each element a table row will be rendered with the icon/title and an additional cell containing the uid.

   3. Line 37 wraps the table rows in a table tag.

Local extensions of the page tree classes

If you search in the source for other places where this class is used you will often find that the class is extended locally in those scripts. This is because it is possible to override certain functions that generate for instance the icon or wraps the title in some way.