FlashMessages ViewHelper `<f:flashMessages>`

This ViewHelper renders the Flash messages (if there are any) as an unsorted list.

Screenshot of two flash message one with success and one with warning severity — Example for the output of flash messages in an Extbase plugin

Go to the source code of this ViewHelper: FlashMessagesViewHelper.php (GitHub).

Table of contents

Quick start: Simple flash message output

You can use the following tag within any Extbase template:

packages/my_extension/Resources/Private/Templates/Something/DoSomething.html

<f:flashMessages />

It displays the flash messages with a standard bootstrap compatible layout.

Adding and displaying flash messages in Extbase

Within an Extbase controller (extending ActionController) you can call method addFlashMessage() to add flash messages to the message queue:

packages/my_extension/Classes/Controller/MyController.php

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\Controller;

use Psr\Http\Message\ResponseInterface;
use TYPO3\CMS\Core\Type\ContextualFeedbackSeverity;
use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;

class MyController extends ActionController
{
    public function demonstrateFlashMessagesAction(): ResponseInterface
    {
        $this->addFlashMessage('This is a success message.');
        $this->addFlashMessage('This is a warning.', 'Warning Headline', ContextualFeedbackSeverity::WARNING);
        return $this->htmlResponse();
    }
}

As mentioned above, they will be displayed when a <f:flashMessages> is displayed within any action of the same controller:

        packages/my_extension/Resources/Private/Templates/My/DemonstrateFlashMessages.html
    

<f:layout name="MyLayout"/>
<f:section name="Content">
    <f:flashMessages />
</f:section>

If you want to display the flash messages in any place outside of the controller you can use the identifier extbase.flashmessages.<pluginNamespace>, for example:

packages/my_extension/Resources/Private/Templates/Other/SomeForm.html

<f:layout name="MyLayout"/>
<f:section name="Content">
    <f:flashMessages queueIdentifier="extbase.flashmessages.tx_myextension_myplugin"/>
</f:section>

Using a specific flash message queue in plain classes

When you use the FlashMessages ViewHelper outside of the Extbase context, supplying the queueIdentifier is mandatory.

When you add a message manually to the queue, you can specify an arbitrary identifier:

// private \TYPO3\CMS\Core\Messaging\FlashMessageService $flashMessageService;

$messageQueue = $this->flashMessageService->getMessageQueueByIdentifier('myQueue');

You can then display messages of only this one queue using the identifier:

<f:flashMessages queueIdentifier="myQueue" />

Output flash messages with a custom layout

Using the argument as you can receive all flash messages in a variable and then handle the rendering yourself within the <f:flashMessages> tag:

packages/my_extension/Resources/Private/Templates/Something/DoSomething.html

<f:flashMessages as="flashMessages">
  <dl class="messages">
    <f:for each="{flashMessages}" as="flashMessage">
      <dt>{flashMessage.code}</dt>
      <dd>{flashMessage.message}</dd>
    </f:for>
  </dl>
</f:flashMessages>

Argument of the FlashMessages ViewHelper

as

Type: string

The name of the current flashMessage variable for rendering inside

queueIdentifier

Type: string

Flash-message queue to use

FlashMessages ViewHelper <f:flashMessages>