Working with requests

You can work with request data directly using PHP superglobals such as $_SERVER, $_GET, or $_POST but the better way is to use Yii's powerful CHttpRequest class that resolves inconsistencies among different web servers, manages cookies, provides some additional security, and has a nice set of OO methods.

How to do it…

You can access the request component in your web application by using Yii::app()->getRequest(). So, let's review the most useful methods and their usage, methods that return different parts of the current URL. In the following table, the returned parts are marked with a bold font.

Methods	Results
getUrl	http://cookbook.local/test/index?var=val
getHostInfo	http://cookbook.local/test/index?var=val
getPathInfo	http://cookbook.local/test/index?var=val
getRequestUri	http://cookbook.local/test/index?var=val
getQueryString	http://cookbook.local/test/index?var=val

The methods that allow us to ensure the request types are getIsPostRequest, getIsAjaxRequest , and getRequestType .

• For example, we can use getIsAjaxRequest to serve different content based on the request type:

  class TestController extends CController
  {
     public function actionIndex()
     {
        if(Yii::app()->request->isAjaxRequest)
           $this->renderPartial('test');
        else
           $this->render('test');
     }
  }

  In the preceding code, we are rendering a view without a layout if the request is made through AJAX.

• While PHP provides superglobals for both POST and GET, Yii allows us to omit some additional checks:

  class TestController extends CController
  {
     public function actionIndex()
     {
        $request = Yii::app()->request;
  
        $param = $request->getParam('id', 1);
        // equals to
        $param = isset($_REQUEST['id']) ? $_REQUEST['id'] : 1;
  
        $param = $request->getQuery('id');
        // equals to
        $param = isset($_GET['id']) ? $_GET['id'] : null;
  
        $param = $request->getPost('id', 1);
        // equals to
        $param = isset($_POST['id']) ? $_POST['id'] : 1;
     }
  }

• getPreferredLanguage tries to determine the user's preferred language. It can't be completely accurate, but it is good to use it as a fallback in case the user has not specified a preferred language manually.

  class TestController extends CController
  {
     public function actionIndex()
     {
        $request = Yii::app()->request;
        $lang = $request->preferredLanguage;
  
        // Trying to get language setting from 
        // Settings table that holds id of the user,
        // setting name and setting value.
        $criteria = new CDbCriteria();
        $criteria->compare('user_id', $request->getQuery('userid'));
        $criteria->compare('key', 'language');
        $setting = Settings::model()->find($criteria);
        if($setting)
           $lang = $setting->value;
  
        Yii::app()->setLanguage($lang);
        
        echo Yii::t('app', 'Language is: ').$lang;
     }
  }

• sendFile allows us to initiate a file download as follows:

  class TestController extends CController
  {
     public function actionIndex()
     {
     $request = Yii::app()->getRequest();
        $request->sendFile('test.txt', 'File content goes here.');
     }
  }

  This action will trigger a file download and send all necessary headers, including content type (mimetype) and content length. The MIME type, if not set manually as a third parameter, will be guessed based on the filename's extension.

• The last thing we are going to show in this chapter is the getCookies method. It returns a CCookieCollection class instance that allows us to work with cookies. As CCookieCollection extends CMap, we can use some native PHP methods as follows:

  class TestController extends CController
  {
     public function actionIndex()
     {
        $request = Yii::app()->request;
        // getting a cookie
        $cookie = $request->cookies['test'];
        if($cookie)
           // printing cookie value
           echo $cookie->value;      
        else {
           // creating new cookie
           $cookie=new CHttpCookie('test','I am a cookie!');
           $request->cookies['test'] = $cookie;
        }
  }

There's more...

If you are working with a lot of cookie values and want to shorten the code provided, then you can use a helper as follows:

class Cookie
{
  public static function get($name)
  {
       $cookie=Yii::app()->request->cookies[$name];
       if(!$cookie)
           return null;

       return $cookie->value;
  }

  public static function set($name, $value, $expiration=0)
  {
       $cookie=new CHttpCookie($name,$value);
       $cookie->expire = $expiration;
       Yii::app()->request->cookies[$name]=$cookie;
  }
}

After you drop this code into protected/components/Cookie.php, you will be able to perform the following:

class TestController extends CController
{
   public function actionIndex()
   {
      $cookie = Cookie::get('test');
      if($cookie)
         echo $cookie;      
      else
         Cookie::set('test','I am a cookie!!');
   }
}