Often multiple validations should be applied to some value in a particular order. The following code demonstrates a way to solve the example from the introduction, where a username must be between 6 and 12 alphanumeric characters:
// Create a validator chain and add validators to it $validatorChain = new Zend_Validate(); $validatorChain->addValidator(new Zend_Validate_StringLength(6, 12)) ->addValidator(new Zend_Validate_Alnum()); // Validate the username if ($validatorChain->isValid($username)) { // username passed validation } else { // username failed validation; print reasons foreach ($validatorChain->getMessages() as $message) { echo "$message\n"; } }
Validators are run in the order they were added to Zend_Validate
. In
the above example, the username is first checked to ensure that its length is between 6 and
12 characters, and then it is checked to ensure that it contains only alphanumeric
characters. The second validation, for alphanumeric characters, is performed regardless of
whether the first validation, for length between 6 and 12 characters, succeeds. This means
that if both validations fail, getMessages()
will return failure messages from
both validators.
In some cases it makes sense to have a validator break the chain if its validation process
fails. Zend_Validate
supports such use cases with the second
parameter to the addValidator()
method. By setting
$breakChainOnFailure
to TRUE
, the added validator will break the
chain execution upon failure, which avoids running any other validations that are determined
to be unnecessary or inappropriate for the situation. If the above example were written as
follows, then the alphanumeric validation would not occur if the string length validation
fails:
$validatorChain->addValidator(new Zend_Validate_StringLength(6, 12), true) ->addValidator(new Zend_Validate_Alnum());
Any object that implements Zend_Validate_Interface
may be used in a
validator chain.