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Callback Validator — Zend Framework 2 2.4.9 documentation

Zend\Validator

Callback Validator

Zend\Validator\Callback allows you to provide a callback with which to validate a given value.

Supported options for Zend\Validator\Callback

The following options are supported for Zend\Validator\Callback:

  • callback: Sets the callback which will be called for the validation.
  • options: Sets the additional options which will be given to the callback.

Basic usage

The simplest usecase is to have a single function and use it as a callback. Let’s expect we have the following function.

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function myMethod($value)
{
    // some validation
    return true;
}

To use it within Zend\Validator\Callback you just have to call it this way:

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$valid = new Zend\Validator\Callback('myMethod');
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

Usage with closures

PHP 5.3 introduces closures, which are basically self-contained or anonymous functions. PHP considers closures another form of callback, and, as such, may be used with Zend\Validator\Callback. As an example:

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$valid = new Zend\Validator\Callback(function($value){
    // some validation
    return true;
});

if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

Usage with class-based callbacks

Of course it’s also possible to use a class method as callback. Let’s expect we have the following class method:

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class MyClass
{
    public function myMethod($value)
    {
        // some validation
        return true;
    }
}

The definition of the callback is in this case almost the same. You have just to create an instance of the class before the method and create an array describing the callback:

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$object = new MyClass;
$valid = new Zend\Validator\Callback(array($object, 'myMethod'));
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

You may also define a static method as a callback. Consider the following class definition and validator usage:

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class MyClass
{
    public static function test($value)
    {
        // some validation
        return true;
    }
}

$valid = new Zend\Validator\Callback(array('MyClass', 'test'));
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

Finally, if you are using PHP 5.3, you may define the magic method __invoke() in your class. If you do so, simply providing an instance of the class as the callback will also work:

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class MyClass
{
    public function __invoke($value)
    {
        // some validation
        return true;
    }
}

$object = new MyClass();
$valid = new Zend\Validator\Callback($object);
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

Adding options

Zend\Validator\Callback also allows the usage of options which are provided as additional arguments to the callback.

Consider the following class and method definition:

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class MyClass
{
    function myMethod($value, $option)
    {
        // some validation
        return true;
    }

    //if a context is present
    function myMethod($value, $context, $option)
    {
        // some validation
        return true;
    }

}

There are two ways to inform the validator of additional options: pass them in the constructor, or pass them to the setOptions() method.

To pass them to the constructor, you would need to pass an array containing two keys, “callback” and “callbackOptions”:

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$valid = new Zend\Validator\Callback(array(
    'callback'        => array('MyClass', 'myMethod'),
    'callbackOptions' => $options,
));

if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

Otherwise, you may pass them to the validator after instantiation:

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$valid = new Zend\Validator\Callback(array('MyClass', 'myMethod'));
$valid->setOptions($options);

if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}

When there are additional values given to isValid() then these values will be added immediately after $value.

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$valid = new Zend\Validator\Callback(array('MyClass', 'myMethod'));
$valid->setOptions($options);

if ($valid->isValid($input, $additional)) {
    // input appears to be valid
} else {
    // input is invalid
}

When making the call to the callback, the value to be validated will always be passed as the first argument to the callback followed by all other values given to isValid(); all other options will follow it. The amount and type of options which can be used is not limited.

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