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Callbacks and plugins

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Maksim Kochkin edited this page Feb 18, 2015 · 1 revision

Blitz supports callbacks like {{ Some::doSomething($params) }} or {{ doSomething($param) }}. With this you can add any function calls to your template.

Basically you can:

  • extend Blitz and use your custom template methods in the template code
  • call any other PHP function like do($something) or Plugin::do($something)

Callbacks were added in 0.7.1.5 but changed in older versions. Current callback API (writing this for 0.7.1.14) works this way:

  • {{ this::method }} calls class method through the template object
  • {{ php::method }} calls PHP function "method"
  • {{ helper::method }} calls static PHP-method
  • {{ method }} calls class method first and PHP-method after (if not found) and vice versa - according to blitz.php_callbacks_first setting. This was added in 0.7.1.14 and by default it's 1 so PHP-method is called first. This can be changed in next versions according to the community reaction.

See the following example:

// calls.php
<?

ini_set("blitz.php_callbacks_first", 1);

$body = <<<BODY
   {{ php::date("Y/m/d H:i") }}
   self-call: {{ this::doSomething() }}
   php-call: {{ php::doSomething() }}
   this+php call: {{ doSomething() }}
   this+php call: {{ doSomething2() }}

BODY;

function doSomething() {
   return 'PHP :: did comething';
}

class View extends Blitz {
   function doSomething() {
       return 'THIS :: did something';
   }

   function __call($a, $b) {
       return '__call handler: '.var_export($a, true).', '.
            str_replace(array("\n","\r"), "", var_export($b, true));
   }
}

$T = new View();
$T->load($body);
$T->display();

?>
fisher@fisher:~/prj/blitz/tests> php5 calls.php
   2010/04/02 23:57
   this-call: THIS :: did something
   php-call: PHP :: did comething
   this+php call: PHP :: did comething
   this+php call: __call handler: 'dosomething2', array ()

To understand how this all works let's see how Blitz examines the call:

  • When there is a namespace and a :: before function, Blitz checks if the namespace is a "hint". "Hints" are reserved namespaces: {{ php::do($params) }}, or {{ this::do($params) }}
    • When namespace is a "hint" ("php" or "this"). Having {{ php::do($params) }} Blitz makes a static php-function call, having {{ this::do($param) }} do() method is called through the current template object.
    • When namespace is not a "hint", Blitz makes a static PHP-call namespace::do($params). If this namespace and function exists - the function will be called.
  • When there was just a function call with no namespace like {{ do($params) }} Blitz works according to priority settings. When blitz.php_callbacks_first is set to 1 Blitz first tries to make a static PHP-function call. If this function doesn't exist - Blitz calls this method through your template controller. When blitz.php_callbacks_first is set to 0, vice versa.

Now we can go back to the example:

  • {{ php::date("Y/m/d H:i") }} - is a PHP-function call
  • {{ this::doSomething() }} - is a "hinted" doSomething() method call through the View object $T
  • {{ php::doSomething() }} - is a "hinted" doSomething() function call from the current function scope
  • {{ doSomething() }} - is a function call from the current function scope because blitz.php_callbacks_first was set to 1
  • {{ doSomething2() }} - Blitz tries to find doSomething2() function in the current scope because blitz.php_callbacks_first was set to 1. There's no such function, so then Blitz makes a method call through the View object $T. This call is handled by __call() because doSomething2() method doesn't exist.
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