Zend_Validate_Callback allows you to provide a callback with which to
validate a given value.
The following options are supported for Zend_Validate_Callback:
callback: Sets the callback which will be called for the validation.
options: Sets the additional options which will be given to the callback.
The simplest usecase is to have a single function and use it as a callback. Let's expect we have the following function.
<?php
function myMethod($value)
{
// some validation
return true;
}
To use it within Zend_Validate_Callback you just have to call it
this way:
<?php
$valid = new Zend_Validate_Callback('myMethod');
if ($valid->isValid($input)) {
// input appears to be valid
} else {
// input is invalid
}
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_Validate_Callback. As an example:
<?php
$valid = new Zend_Validate_Callback(function($value){
// some validation
return true;
});
if ($valid->isValid($input)) {
// input appears to be valid
} else {
// input is invalid
}
Of course it's also possible to use a class method as callback. Let's expect we have the following class method:
<?php
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:
<?php
$object = new MyClass;
$valid = new Zend_Validate_Callback(array($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:
<?php
class MyClass
{
public static function test($value)
{
// some validation
return true;
}
}
$valid = new Zend_Validate_Callback(array('MyClass', 'test'));
if ($valid->isValid($input)) {
// input appears to be valid
} else {
// input is invalid
}
Finally, if you are using PHP 5.3, you may define the magic method
__invoke() in your class. If you do so, simply providing an
instance of the class as the callback will also work:
<?php
class MyClass
{
public function __invoke($value)
{
// some validation
return true;
}
}
$object = new MyClass();
$valid = new Zend_Validate_Callback($object);
if ($valid->isValid($input)) {
// input appears to be valid
} else {
// input is invalid
}
Zend_Validate_Callback also allows the usage of options which
are provided as additional arguments to the callback.
Consider the following class and method definition:
<?php
class MyClass
{
function myMethod($value, $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 "options":
<?php
$valid = new Zend_Validate_Callback(array(
'callback' => array('MyClass', 'myMethod'),
'options' => $option,
));
if ($valid->isValid($input)) {
// input appears to be valid
} else {
// input is invalid
}
Otherwise, you may pass them to the validator after instantiation:
<?php
$valid = new Zend_Validate_Callback(array('MyClass', 'myMethod'));
$valid->setOptions($option);
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.
<?php
$valid = new Zend_Validate_Callback(array('MyClass', 'myMethod'));
$valid->setOptions($option);
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.