Querying database for existing username with Zend and doctrine - database

Question

I am querying database records to check if a username already exists this way:
$q = Doctrine_Query::create()
->from('Tcc_Model_User u')
->where('u.Username = ?', $input['Username']);
$object = $q->fetchOne();
if(is_object($object)) {
// not sure what to do here
} else {
// ok to record
What I cannot make it work is how to show a message that username is already taken next to the Username field of the submitted form. Could please anyone help me? Really appreciated any help. Thank you
EDITED:
Thanks to Drew010 I solved the above problem by adding:
$form->getElement('Username')->addError('Sorry, that username is already taken!');
in the first of the conditional statement. Thank again drew010.

Answer 1

Since you are using Zend_Form, there is a validator that can do this for you.
See Zend_Validate_DbNoRecordExists
They give an example for validating that a given username does not exist in the database.
Here is an example from one of my applications, the third validator checks that the username does not already exist:
$this->addElement('text', 'username', array(
'label' => 'User Name:',
'required' => true,
'validators' => array('NotEmpty'),
'decorators' => $this->elementDecorators,
'validators' => array(
array('StringLength', true, array('min' => 4,
'messages' => array(
Zend_Validate_StringLength::TOO_SHORT =>
'Account username must be at least %min% characters'
)
)),
array('Regex', true, array('pattern' => '/^\w(?:[\w\d\.\-_]+)(?:\w|\d)$/',
'messages' => array(
Zend_Validate_Regex::NOT_MATCH =>
"The username contained invalid characters"
)
)),
array('Db_NoRecordExists', true, array(
'table' => 'accounts', 'field' => 'username',
'messages' => array(
Zend_Validate_Db_NoRecordExists::ERROR_RECORD_FOUND =>
"An account with the username '%value%' is already registered"
)
))
)
));
Also, for future reference, if you do extended validation you can't do with a validator, you can add an error to a specific form element like this:
if ($something_was_wrong) {
$form->getElement('username')
->addError('Username already exists!');
}

Answer 2

I would create a separate Doctrine-based validator modeled on the Zend_Validate_Db_NoRecordExists validator and add that validator directly to the element
The validator:
class My_Validate_UsernameAvailable extends Zend_Validate_Abstract
implements Zend_Validate_Interface
{
const NOT_AVAILABLE = 'usernameAvailableNot';
protected $_messageTemplates = array(
self::NOT_AVAILABLE => "Username is not available",
);
public function isValid($value)
{
$q = Doctrine_Query::create()
->from('Tcc_Model_User u')
->where('u.Username = ?', $value);
if ($q->fetchOne()){
$this->_error(self::NOT_AVAILABLE);
return false;
}
return true;
}
}
Then in the form, attached to the username element:
'validators' => array(
// your other valiadators
array(new My_Validate_UsernameAvailable(), true),
),
Then there is no extra handling required in the controller.