StellarTech Blog

I am really enjoying the flexibility that CakePHP 1.2 gives when it comes to validating forms. While there is a decent list of validation rules right out of the box, creating your own is pretty easy using the userDefined method. Thanks to Daniel and his article at www.4webby.com/blog for turning me on to this method. Since I like and learn from code examples, I’m going to use validating a name field as an example in this article. Here are the rules I would like to achieve:

1. Alphanumeric characters are allowed. Numbers are allowed for names like Fred Jones the 2nd.
2. White space must be allowed.
3. The period character must be allowed.
4. The name field cannot be empty
5. The name field must be a minimum of 3 characters or more.

That said I would also like different messages printed for each in the following order:

1. For leaving a field empty.
2. For not entering 3 or more characters in the field.
3. For entering non alphanumeric, white space, or the period character.

Setting It Up

Setting up multiple rules in the validation attribute is done like this:
public $validate = array(
'name' => array(
'alphaNumericws'=>array(
'rule'=>array('userDefined', 'MyModel', 'wAlphaNumeric'),
'message'=>'Only alphabets, numbers, white space, and the period characters are allowed.'
),
'minlength'=>array(
'rule'=>array('minLength', '3'),
'message'=>'Minimum length of 3 characters.'
),
'notempty'=>array(
'rule'=>array('userDefined', 'MyModel', 'notEmpty'),
'message'=>'Please enter in your name.'
)
)
The syntax for using userDefined goes like this:
'rule'=>array('userDefined', 'model_class_where_defined_method_is_located', 'methodName')
In the example I’ve added 2 of my own defined validation methods: wAlphaNumeric and notEmpty. While CakPHP already has an alphaNumeric method it doesn’t let you white list any characters. In this case I wanted to white list ‘white space’ and the period character to knock out rules 1, 2, and 3 from the list above. Here is the corresponding method:
/** check alpha numeric but white space is allowed */
public function wAlphaNumeric($check, $params) {
$valid = false;
$pattern = "^([a-zA-Z0-9\ \.]+)$";
if(ereg($pattern, $check, $test)) {
$valid = true;
}
return $valid;
}
My second user defined rule is nothing more than a replacement for VALID_NOT_EMPTY in CakePHP 1.1. I read that this has been marked to be discontinued and did not want to use it. Here is the method:
/** VALID_NOT_EMPTY replacement */
public function notEmpty($check, $params) {
$valid = false;
if(!empty($check)) {
$valid = true;
}
return $valid;
}
Here is the full code example:
public $name = 'MyModel';
public $validate = array(
'name' => array(
'alphaNumericws'=>array(
'rule'=>array('userDefined', 'MyModel', 'wAlphaNumeric'),
'message'=>'Only alphabets, numbers, white space, and the period characters are allowed.'
),
'minlength'=>array(
'rule'=>array('minLength', '3'),
'message'=>'Minimum length of 3 characters.'
),
'notempty'=>array(
'rule'=>array('userDefined', 'MyModel', 'notEmpty'),
'message'=>'Please enter in your name.'
)
)
);

/** check alpha numeric but white space is allowed */
public function wAlphaNumeric($check, $params) {
$valid = false;
$pattern = "^([a-zA-Z0-9\ \.]+)$";
if(ereg($pattern, $check, $test)) {
$valid = true;
}
return $valid;
}
/** VALID_NOT_EMPTY replacement */
public function notEmpty($check, $params) {
$valid = false;
if(!empty($check)) {
$valid = true;
}
return $valid;
}
Using the userDefined() method is extremely flexible. Another cool thing about doing it this way is that I can share the validation methods in other models.