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Complex Validation with classes or callback methods February 11, 2006

Posted by rossoft in CakePHP.

Complex Validation

There are several implementations of custom validation made by CakePHP users. I just show you another one. Some of the stuff is from CakeBaker and other cakers solution

My solution has these features:
* Each field can be validated for more than one validator. You can show a different message for know what validator has failed.
* A validator can be: a regular expression, a callback method of your model or a validator subclass. With validator subclasses you can share a custom validator between apps easily (simply put a file in the validators folder)

1. Edit the /app/app_model.php (if not exists, copy from /cake/app_model.php)
Edit and merge this with your file:

vendor('validator'. DS. 'validator');

class AppModel extends FixModel 

   	function invalidFields($data)


   		return validator_invalidFields($this,$data);	


2. Download this and uncompress into your /vendors folder. You will get a validator folder.

3. Copy to the file /app/helpers/error.php

class ErrorHelper extends Helper
    function showMessage($target)
        list($model, $field) = explode('/', $target);

        if (isset($this->validationErrors[$model][$field]))
            return sprintf('<div class="error_message">%s</div>',
            return null;

4. Ready to go!! Example of usage:

var $validate=
'empresa'=>array(array(VALID_NOT_EMPTY,'This is not optional'), array(VALID_UNIQUE,'This value is repeated')),
	 'responsable'=>array(array(VALID_NOT_EMPTY, 'This is not optional')),

     'other'=>array(VALID_UNIQUE,'Error in this field',array(12,42))


In the example, the code field, needs to be a unique field not empty.
VALID_NOT_EMPTY is a CakePHP generic regexp. VALID_UNIQUE is a custom class validator (is the file /vendors/validator/validators/unique.php). Have a look at it for the syntax of custom classes. If you create the class MyownValidator, simply put the file myown.php in this folder, and the constant VALID_MYOWN will be automatically populated in all models for it’s use.

In the example, the other field, is validated with the validator VALID_BETWEEN. This class validator not exists (the file /vendors/validator/validators/between.php doesn’t exists). Then, you will get a notice because the constant VALID_BETWEEN is not defined. This is a custom callback function. In your model or app_model, define the constant like this:
Then, in your model, create this function (is equivalent of a BetweenValidator class, the method has precedence)

function BetweenValidator($data,$field_name, $validator_params)
	if (..) return true;
    else return false;

Then in the example, this function will be called with the $data array, $field_name=’other’ and $validator_params=array(12,42).

(If you don’t want to define the VALID_BETWEEN constant, simply put the value ‘VALID_BETWEEN’ in the $validate array )

5. Show the error messages in the view
a) Include the error helper in your controller (var $helpers=array(‘xxx’,’yyy’,’Error’)

b) Use this in your view:


$elementName is in the form Model/field

6. Test it !



1. rossoft - April 22, 2006

I’ve extended FixModel class at app_model.php, if you don’t use flexifix, then change app_model to

vendor(‘validator’. DS. ‘validator’);
class AppModel extends Model

function invalidFields($data)


return validator_invalidFields($this,$data);


2. rossoft - April 22, 2006

Complete model example

array(VALID_NOT_EMPTY,’Please enter your username.’),
array(VALID_ALPHANUMERIC,’Invalid username. (no special characters – !*^%>+ etc)’),
array(VALID_LENGTH,’Invalid username. Must be between 4 and 16 characters.’,array(4,16))
array(VALID_NOT_EMPTY, ‘Please enter your password’),
array(VALID_LENGTH,’Invalid password. Must be between 4 and 16 characters.’,array(4,16))

function LengthValidator($data,$field_name, $validator_params){
return (strlen($field_data)>=$validator_params[0] &&strlen($field_data)

3. Naonak - May 6, 2006

To validate field only if it required :

class AppModel extends Model

function invalidFields($data)
if( isset($data[$this->name]) ){
foreach ($this->validate as $field=>$valid) {
$can_be_empty = true;

foreach ($valid as $v) {
if($v[0] == VALID_NOT_EMPTY){
$can_be_empty = false;

if($can_be_empty && empty($data[$this->name][$field])
&& (string)$data[$this->name][$field] != ‘0’){
return validator_invalidFields($this, $data);

Bug fix for cake 1.0 on model_extension.php :

function validator_invalidFields(&$model,$data=array())
if (!empty($model->validationErrors))
return $model->validationErrors;

Other bug not solved :

Method “saveField” with validation don’t work correctly. It valide all fields.


4. Naonak - May 6, 2006

Fix the second bug on model_extension.php on line 124:
if (isset($data[$model->name][$field_name]))
else {
return true;// instead of $value=”;

5. Naonak - May 6, 2006

My solution to validate field only if it required is not very smart.

Better idea Rossoft ?

6. Mark Quinn - August 1, 2006

the loadValidators function in vendors/validator/validator.php has a slight error, in that it will try and include every file in the validators subdirectory, regardless of file types.

As many editors save backup files, this can be a problem.

Change the function to read:

function loadValidators() {

// Cargar las clases restantes
$validator_dh = opendir( VALIDATORS_DIR );
while (false !== ($validator_filename = readdir($validator_dh))) {

if (! is_dir($validator_filename)
&& (preg_match(‘/(.+)\\.php$/’, $validator_filename ))) {

loadValidator( $validator_filename );


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