With custom template operators you can call any PHP function from a template. This example explains how to create two operators, one with two parameters, and one without parameters. If you want to call a built-in PHP function, such as strrev(), then you probably want this page instead.

Create these directories:
extension/myextension
extension/myextension/autoloads
extension/myextension/settings

Create
extension/myextension/settings/site.ini.append
with the following content:

[TemplateSettings]

ExtensionAutoloadPath[]=myextension

This suggests that eZ publish should look for autoload files in this directory.

Create
extension/myextension/autoloads/eztemplateautoload.php
with the following content:

<?php

 

// Operator autoloading

 

$eZTemplateOperatorArray = array();

 

$eZTemplateOperatorArray[] =

 array( 'script' => 'extension/myextension/autoloads/mystringoperators.php',

        'class' => 'MyStringOperators',

        'operator_names' => array( 'addstrings', 'helloworld' ) );

 

?>

This tells eZ publish that we have two operators, which class they are in, and which file.

Create
extension/myextension/autoloads/mystringoperators.php
with the following content:

<?php

 

class MyStringOperators

{

   /*!

    Constructor

   */

   function MyStringOperators()

   {

       $this->Operators = array( 'addstrings',

                                 'helloworld' );

   }

 

   /*!

    Returns the operators in this class.

   */

   function &operatorList()

   {

       return $this->Operators;

   }

 

   /*!

    

eturn true to tell the template engine that the parameter list

   exists per operator type, this is needed for operator classes

   that have multiple operators.

   */

   function namedParameterPerOperator()

   {

       return true;

   }

 

   /*!

    The first operator has two parameters, the other has none.

    See eZTemplateOperator::namedParameterList()

   */

   function namedParameterList()

   {

       return array( 'addstrings' => array( 'string1' => array( 'type' => 'string',

                                                                'required' => true,

                                                                'default' => '' ),

                                            'string2' => array( 'type' => 'string',

                                                                'required' => true,

                                                                'default' => '' ) ),

                     'helloworld' => array() );

   }

 

   /*!

    Executes the needed operator(s).

    Checks operator names, and calls the appropriate functions.

   */

   function modify( &$tpl, &$operatorName, &$operatorParameters, &$rootNamespace,

                    &$currentNamespace, &$operatorValue, &$namedParameters )

   {

       switch ( $operatorName )

       {

           case 'addstrings':

           {

               $operatorValue = $this->addStrings( $namedParameters['string1'],

                                                   $namedParameters['string2'] );

           } break;

           case 'helloworld':

           {

               $operatorValue = $this->helloWorld();

           } break;

       }

   }

 

   /*!

    

eturn the sum of two strings.

   */

   function addStrings( $string1, $string2 )

   {

       return $string1 . $string2;

   }

 

   /*!

    

eturn a famous string.

   */

   function helloWorld()

   {

       return 'Hello World!';

   }

 

   /// privatesection

   var $Operators;

}

 

?>

This is the actual implementation of our two operators. The logic here connects the two template operators addstrings and helloworld with the PHP functions addStrings( $string1, $string2 ) and helloWorld().

Activate the extension. This page explains how to do it: Introduction to extensions

Now you should be ready to start using your new operators. Try this in a template:

<p>{addstrings( 'Forty', 'two' )}</p>

 

<p>{helloworld()}</p>

You should see the output "Fortytwo" and "Hello World!".