Adding custom validation rules - Webform Validation hooks

This page describes how to write custom validation rules for your webforms. This requires installation of the Webform and Webform Validation modules. Drupal 7 only.

The following code should be implemented in your own custom module.

Adding custom validation rules

The following steps will let you add custom validators through your module:

1/ Implement hook_webform_validation_validators().
This hook implementation should return an array of validator key => options array entries.
The options array can contain the following configuration keys:

• name (required): name of the validator
• component types (required): defines which component types can be validated by this validator. Specify 'all' to allow all types
• custom_error (optional): define whether a user can specify a custom error message upon creating the validation rule.
• custom_data (optional): define whether custom data can be added to the validation rule
• min_components (optional): define the minimum number of components to be selected for creating a validation rule
• max_components (optional): define the maximum number of components to be selected for creating a validation rule
• description (optional): provide a descriptive explanation about the validator

See function webform_validation_webform_validation_validators() in webform_validation.validators.inc for a live example

2/ Implement hook hook_webform_validation_validate($validator_name, $items, $components, $rule).
This hook gets passed 4 parameters, which will allow you to react to your custom validator (or any other validator for that matter).
Explanation about these parameters:

• $validator_name: this is the validator name (i.e. array key as entered in hook_webform_validation_validators)
• $items: array containing user submitted entries to be validated.
• $components: this array contains the definitions of the webform components in your form
• $rule: this array contains the details of your validation rule

See function webform_validation_webform_validation_validate() in webform_validation.validators.inc for a live example

Additional hooks

The hook hook_webform_validation($type, $op, $data) can be used to react on various webform_validation based actions.`

• $type - possible values: 'rule'
• $op - possible values: 'add', 'edit', 'delete'
• $data - array with rule data in case of $op add/edit, rule id in case of $op delete.

The hook hook_webform_validator_alter(&$validators) can be used to alter the array of validators that is being generated by hook_webform_validation_validators().

• $validators - array of validators as supplied by modules implementing hook_webform_validation_validators().

Example

/**
 * Implements hook_webform_validation_validators().
 */
function idvalidation_webform_validation_validators() {
  return array(
    'validate_id' => array(
      'name' => "Validate ID",
      'description' => "Validate ID Description",
      'component_types' => array(
        'textfield',
      ),
    )
  );
}

/**
 * Implements hook_webform_validation_validate().
 */
function idvalidation_webform_validation_validate($validator_name, $items, $components, $rule) {
  if ($items) {
    switch ($validator_name) {
      case 'validate_id':
        $valid_ids = array(1, 2, 3); // get this from database source instead
        $errors = array();
        foreach ($items as $key => $val) {
          if ($val && (!in_array($val, $valid_ids))) {
            $errors[$key] = t('%item is not a valid ID', array('%item' => $components[$key]['name']));
          }
        }
        return $errors;
        break;
    }
  }
}