====== How to Validate  ======

**The Controller file at app/controllers/post_controller.php**

<code php>
class PostController extends ApplicationController {

  function create(){
    $this->Post =& new Post($this->params["post"]);
    if($this->Post->save()){
      $this->redirectToAction("show", array('id' => $Post->getId()));
    }else{
      $this->Post->errors = $this->Post->getErrors();
    }
  }

  //...
  function show(){
  }

}
</code>

** The View file at app/views/post/show.tpl **

<code html>
{?Post.errors}
  The post couldn't be saved due to these errors:
  <ul>
  {loop Post.errors}
    <li>{error}</li>
  {end}
  </ul>
{end}

<%= form "post" %>
</code>

or even shorter:

<code ruby>
<%= error_messages_for 'post' %>
</code>

** The Model file at app/models/post.php **

<code php>
class Post extends ActiveRecord
{
    function validate(){
      $this->validatesPresenceOf( array('title', 'body'), "Missing required field");
      $this->get('title') > 10 ? $this->addError("title", "must be at most 10 characters") : null;
    }
}
</code>



===== More information =====

  * [[understanding-validations|Understanding Validations]]
  * [[http://api.akelos.org/ActiveRecord/Base/AkActiveRecord.html#methodvalidate|Validation API Documentation]] has all sorts of details about what methods are available.  Some of them follow:
==== validatesAcceptanceOf ====
**Syntax**:\\
<code php>
$this->validatesAcceptanceOf(accept $attribute_names, [ $message = 'accepted'], [ $accept = 1]);
</code>
==== validatesAssociated ====
**Syntax**:\\
<code php>
$this->validatesAssociated($attribute_names, [ $message = 'invalid']);
</code>
==== validatesConfirmationOf ====
**Syntax**:\\
<code php>
$this->validatesConfirmationOf($attribute_names, [ $message = 'confirmation']);
</code>
**Description**:\\
Note: When using validatesConfirmationOf() make sure you also use validatesPresenceOf() if you want to make sure the field exists.
==== validatesExclusionOf ====
**Syntax**:\\
<code php>
$this->validatesExclusionOf($attribute_names, 
    $array_of_possibilities, [ $message = 'exclusion'], [ $allow_null = false]);
</code>
==== validatesFormatOf ====
**Syntax**:\\
<code php>
$this->validatesFormatOf($attribute_names, 
    $regular_expression, [ $message = 'invalid'], [ $regex_function = 'preg_match']);
</code>
==== validatesInclusionOf ====
**Syntax**:\\
<code php>
$this->validatesInclusionOf($attribute_names, 
    $array_of_possibilities, [ $message = 'inclusion'], [ $allow_null = false]);
</code>
==== validatesLengthOf ====
**Syntax**:\\
<code php>
$this->validatesLengthOf($attribute_names, [ $options = array()]);
</code>
==== validatesNumericalityOf ====
**Syntax**:\\
<code php>
$this->validatesNumericalityOf($attribute_names, 
    [ $message = 'not_a_number'], [ $only_integer = false], [ $allow_null = false]);
</code>
==== validatesPresenceOf ====
**Syntax**:\\
<code php>
$this->validatesPresenceOf($attribute_names, [ $message = 'blank']);
</code>
==== validatesSizeOf ====
**Syntax**:\\
<code php>
$this->validatesSizeOf($attribute_names, [ $options = array()]);
</code>
==== validatesUniquenessOf ====
**Syntax**:\\
<code php>
$this->validatesUniquenessOf($column_name [,$options = array('message' => "has already been taken")]);
</code>
The $options are:
  * ''message'' - Specifies a custom error message
  * ''scope'' - Ensures that the uniqueness is restricted to a condition of "scope = record.scope"
  * ''case_sensitive'' - Looks for an exact match. Ignored by non-text columns (true by default).
  * ''if'' - Specifies a method to call or a PHP statement to evaluate to determine if the validation should occur.   A method should return a boolean value; A statement should evaluate to a boolean value.
    * 'if' => 'allowValidation'
    * 'if' => '$this->signup_step > 2')
**Description**:\\
When the record is created, a check is performed to make sure that no record exists in the database with the given value for the specified attribute (column). When the record is updated, the same check is made but disregards the record itself.\\
**Examples**:\\
In the model, we write:
<code php>
class Person extends ActiveRecord 
{ 
    function validate() 
    { 
        $this->validatesUniquenessOf('passport_number'); 
        $this->validatesUniquenessOf('user_name', array('scope' => "account_id")); 
    }
}
</code>
It can also validate whether the value of the specified attributes are unique based on multiple scope parameters. For example, making sure that a teacher can only be on the schedule once per semester for a particular class.<code php>
class TeacherSchedule extends ActiveRecord
{
    function validate()
    {
        $this->validatesUniquenessOf('passport_number'); 
        $this->validatesUniquenessOf('teacher_id', array('scope' => array("semester_id", "class_id")); 
    }
}
</code>