How to work with flash messages

Tutorials

flash message, understanding

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Setting flash messages
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**A flash message is used in order to keep a message in session through one or several requests of the same user**. By default, it is removed from session after it has been displayed to the user. Flash messages are usually used in combination with HTTP redirections, because in this case there is no view, so messages can only be displayed in the request that follows redirection. **A flash message has a name and a content** (AKA key and value). It is an entry of an associative array. The name is a string: often "notice", "success", or "error", but it can be anything. The content is usually a string. You can put HTML tags in your message if you display it raw. You can also set the message value to a number or an array: it will be serialized and kept in session like a string.
 
 
Flash messages can be set using the [setFlash()](http://www.yiiframework.com/doc/api/CWebUser#setFlash) Method of [CWebUser]. For example, if you would like to inform the user that his changes were successfully saved, you could add the following line to your Controller:```

In this example we used the key 'success'. If you want to define more than one flash messages, you will have to use different keys. You can put HTML tags in your message if you display it raw. Displaying flash messages -----------------------
 
To check for flash messages we use the [hasFlash()](http://www.yiiframework.com/doc/api/CWebUser#hasFlash) Method and to obtain the flash message we use the [getFlash()](http://www.yiiframework.com/doc/api/CWebUser#getFlash) Method. Since Yii v1.1.3, there is also a method [getFlashes()](http://www.yiiframework.com/doc/api/CWebUser#getFlashes) to fetch all the messages.

By default, fetching a message deletes it from the session. This means that a message is meant to be displayed only on the first page served to the user. The fetching methods have a boolean parameter that can change this behavior. See the API links in the previous paragraph.These few lines of code will make a flash message with the key "success" visible to the user within a div of class "info". The message will be displayed until this or another page is (re)loaded in the browser.

If you want to always display all the flash messages, then you should add a block to your layout (by default `protected/views/layout/main.php`). Here is a more elaborate example:

```php$flashMessages = Yii::app()->user->getFlashes();
if ($flashMessages) {
echo '<divul class="flashes">'; foreach($flashMessages as $key => $message) { echo '<li><div class="flash-' . $key . '">' . $message . "</div></li>\n"; } echo '</divul>'; } ?> ``` The default CSS created by the Yii script `yiic webapp` has directives for three classes of flash messages on a div tag: `flash-error`, `flash-notice`, `flash-success`.

The best way to know if some flash messages are set is to check if `Yii::app()->user->getFlashes()` is empty. Since v1.1.7, Yii keeps an associative array of the flash keys in the form `array("key1" => 0, ...)`, or `null` if not flash message is set. You can fetch this with `Yii::app()->user->getState(CWebUser::FLASH_COUNTERS)` but this is not recommended, as Yii could change this internal process.#### Further readings (JS):

 
- More information about the jQuery effects can be found [here](http://docs.jquery.com/Effects). - [Using CJuiDialog to display flash Messages in Dialogues](http://www.yiiframework.com/wiki/79/using-cjuidialog-to-display-flash-messages-in-dialogues "Using CJuiDialog to display flash Messages in Dialogues") ## Links
 
- [CWebUser API](http://www.yiiframework.com/doc/api/1.1/CWebUser) - A more specific use of flash messages: [An easy way to display a success page using flash messages](http://www.yiiframework.com/wiki/172/an-easy-way-to-display-a-success-page-using-flash-messages/)