yii 验证码的使用和验证过程，yii验证码验证过程_PHP教程

public function actions(){
return array( 
// captcha action renders the CAPTCHA image displayed on the contact page
'captcha'=>array(
'class'=>'CCaptchaAction',
'backColor'=>0xFFFFFF, 
'maxLength'=>'8', // 最多生成几个字符
'minLength'=>'7', // 最少生成几个字符
'height'=>'40',
'width'=>'230',
), 
); 

}

public function accessRules(){
return array(
array('allow',
'actions'=>array('captcha'),
'users'=>array('*'),
),
);
}

<div class="control-group">
<?php $this->widget('CCaptcha',array(
'showRefreshButton'=>true,
'clickableImage'=>false,
'buttonLabel'=>'刷新验证码',
'imageOptions'=>array(
'alt'=>'点击换图',
'title'=>'点击换图',
'style'=>'cursor:pointer',
'padding'=>'10')
)); ?>
</div>

<?php

/**
* LoginForm class.
* LoginForm is the data structure for keeping
* user login form data. It is used by the 'login' action of 'SiteController'.
*/
class LoginForm extends CFormModel
{
public $username;
public $password;
public $rememberMe;
public $verifyCode;
private $_identity;

/**
* Declares the validation rules.
* The rules state that username and password are required,
* and password needs to be authenticated.
*/
public function rules(){
return array(
// username and password are required
//	array('username, password', 'required'),
array('username','required','message'=>'登录帐号不能为空'),
array('password','required','message'=>'密码不能为空'),
array('verifyCode','required','message'=>'验证码不能为空'),
array('verifyCode','captcha', 'on'=>'login','allowEmpty'=>!Yii::app()->admin->isGuest),
// rememberMe needs to be a boolean
array('rememberMe', 'boolean'),
// password needs to be authenticated
array('password', 'authenticate'),
);
}

/**
* Declares attribute labels.
*/
public function attributeLabels()
{
return array(
'rememberMe'=>'下次记住我',
'verifyCode' =>'验证码'
);
}

/**
* Authenticates the password.
* This is the 'authenticate' validator as declared in rules().
*/
public function authenticate($attribute,$params)
{
if(!$this->hasErrors())
{
$this->_identity=new UserIdentity($this->username,$this->password);
if(!$this->_identity->authenticate())
$this->addError('password','帐号或密码错误.');
}
}

public function validateVerifyCode($verifyCode){
if(strtolower($this->verifyCode) === strtolower($verifyCode)){
return true;
}else{
$this->addError('verifyCode','验证码错误.');
}
}


/**
* Logs in the user using the given username and password in the model.
* @return boolean whether login is successful
*/
public function login(){
if($this->_identity===null){
$this->_identity=new UserIdentity($this->username,$this->password);
$this->_identity->authenticate();
}
if($this->_identity->errorCode===UserIdentity::ERROR_NONE){
$duration=$this->rememberMe ? 3600*24*30 : 0; // 30 days
Yii::app()->user->login($this->_identity,$duration);
return true;
}else{
return false;
}	
}
}

public function actionLogin(){
$model=new LoginForm;
if(isset($_POST['ajax']) && $_POST['ajax']==='login-form'){
echo CActiveForm::validate($model);
Yii::app()->end();
}

if(isset($_POST['LoginForm'])){
$model->attributes=$_POST['LoginForm'];
// validate user input and redirect to the previous page if valid
if($model->validate() && 
$model->validateVerifyCode($this->createAction('captcha')->getVerifyCode()) && 
$model->login()){
$this->redirect(CController::createUrl('default/index'));
}

}
$this->render('login',array('model'=>$model));
}