One Rule Per Field :: Data Validation :: Common Tasks With CakePHP :: الدليل

4.1.2 One Rule Per Field

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This definition technique allows for better control of how the validation rules work. But before we discuss that, let’s see the general usage pattern adding a rule for a single field:

var $validate = array(
    'fieldName1' => array(
        'rule' => 'ruleName', // or: array('ruleName', 'param1', 'param2' ...)
        'required' => true,
        'allowEmpty' => false,
        'on' => 'create', // or: 'update'
        'message' => 'Your Error Message'
    )
);

var $validate = array(
'fieldName1' => array(
'rule' => 'ruleName', // or: array('ruleName', 'param1', 'param2' ...)
'required' => true,
'allowEmpty' => false,
'on' => 'create', // or: 'update'
'message' => 'Your Error Message'
)
);

The 'rule' key is required. If you only set 'required' => true, the form validation will not function correctly. This is because 'required' is not actually a rule.

As you can see here, each field (only one field shown above) is associated with an array that contains five keys: ‘rule’, ‘required’, ‘allowEmpty’, ‘on’ and ‘message’. Let’s have a closer look at these keys.

4.1.2.1 rule

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The 'rule' key defines the validation method and takes either a single value or an array. The specified 'rule' may be the name of a method in your model, a method of the core Validation class, or a regular expression. For more information on the rules available by default, see Core Validation Rules.

If the rule does not require any parameters, 'rule' can be a single value e.g.:

var $validate = array(
    'login' => array(
        'rule' => 'alphaNumeric'
    )
);

var $validate = array(
'login' => array(
'rule' => 'alphaNumeric'
)
);

If the rule requires some parameters (like the max, min or range), 'rule' should be an array:

var $validate = array(
    'password' => array(
        'rule' => array('minLength', 8)
    )
);

var $validate = array(
'password' => array(
'rule' => array('minLength', 8)
)
);

Remember, the 'rule' key is required for array-based rule definitions.

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4.1.2.2 required

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This key should be assigned to a boolean value. If ‘required’ is true, the field must be present in the data array. For example, if the validation rule has been defined as follows:

var $validate = array(
    'login' => array(
        'rule' => 'alphaNumeric',
        'required' => true
    )
);

var $validate = array(
'login' => array(
'rule' => 'alphaNumeric',
'required' => true
)
);

The data sent to the model’s save() method must contain data for the login field. If it doesn’t, validation will fail. The default value for this key is boolean false.

required => true does not mean the same as the validation rule notEmpty(). required => true indicates that the array key must be present - it does not mean it must have a value. Therefore validation will fail if the field is not present in the dataset, but may (depending on the rule) succeed if the value submitted is empty ('').

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4.1.2.3 allowEmpty

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If set to false, the field value must be "nonempty", where "nonempty" is defined as !empty($value) || is_numeric($value). The numeric check is so that CakePHP does the right thing when $value is zero.

The difference between required and allowEmpty can be confusing. 'required' => true means that you cannot save the model without the key for this field being present in $this->data (the check is performed with isset); whereas, 'allowEmpty' => false makes sure that the current field value is "nonempty", as described above.

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4.1.2.4 on

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The ‘on’ key can be set to either one of the following values: ‘update’ or ‘create’. This provides a mechanism that allows a certain rule to be applied either during the creation of a new record, or during update of a record.

If a rule has defined ‘on’ => ‘create’, the rule will only be enforced during the creation of a new record. Likewise, if it is defined as ‘on’ => ‘update’, it will only be enforced during the updating of a record.

The default value for ‘on’ is null. When ‘on’ is null, the rule will be enforced during both creation and update.

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4.1.2.5 message

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The ‘message’ key allows you to define a custom validation error message for the rule:

var $validate = array(
    'password' => array(
        'rule' => array('minLength', 8),
        'message' => 'Password must be at least 8 characters long'
    )
);

var $validate = array(
'password' => array(
'rule' => array('minLength', 8),
'message' => 'Password must be at least 8 characters long'
)
);

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4.1.2.6 last

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Setting the 'last' key to true will cause the validator to stop on the rule if it fails instead of continuing with the next rule. This is handy if you want validation to stop if the field is notEmpty in a multi-rule field.

var $validate = array(
    'username' => array(
        'usernameRule-1' => array(
            'rule' => 'notEmpty',  
            'message' => 'Please enter a username.',
            'last' => true
         ),
        'usernameRule-2' => array(
            'rule' => array('minLength', 8),  
            'message' => 'Minimum length of 8 characters.'
        )  
    )
);