The FlashMessenger helper is used to render the messages of the FlashMessenger MVC plugin.

Basic Usage

When only using the default namespace for the FlashMessenger, you can do the following:

// Usable in any of your .phtml files
echo $this->flashMessenger()->render();

The first argument of the render() function is the namespace. If no namespace is defined, the default Zend\Mvc\Controller\Plugin\FlashMessenger::NAMESPACE_DEFAULT will be used, which translates to default.

// Usable in any of your .phtml files
echo $this->flashMessenger()->render('error');

// Alternatively use one of the pre-defined namespaces 
// (aka: use Zend\Mvc\Controller\Plugin\FlashMessenger;)
echo $this->flashMessenger()->render(FlashMessenger::NAMESPACE_SUCCESS);

CSS Layout

The FlashMessenger default rendering adds a CSS class to the generated HTML, that matches the defined namespace that should be rendered. While it may work well for the default cases, every so often you may want to add specific CSS classes to the HTML output. This can be done while making use of the second parameter of the render() function.

// Usable in any of your .phtml files
echo $this->flashMessenger()->render('error', ['alert', 'alert-danger']);

The output of this example, using the default HTML rendering settings, would look like this:

<ul class="alert alert-danger">
    <li>Some FlashMessenger Content</li>
    <li>You, the developer, are AWESOME!</li>

HTML Layout

Aside from modifying the rendered CSS classes of the FlashMessenger, you are furthermore able to modify the generated HTML as a whole to create even more distinct visuals for your flash messages. The default output format is defined within the source code of the FlashMessenger view helper itself.

// Zend/View/Helper/FlashMessenger.php#L41-L43
protected $messageCloseString     = '</li></ul>';
protected $messageOpenFormat      = '<ul%s><li>';
protected $messageSeparatorString = '</li><li>';

These defaults exactly match what we're trying to do. The placeholder %s will be filled with the CSS classes output.

To change this, all we need to do is call the respective setter methods of these variables and give them new strings; for example:

// In any of your .phtml files:
echo $this->flashMessenger()

The above code sample then would then generate the following output:

<div class="success">
    <p>Some FlashMessenger Content</p>
    <p>You, who's reading the docs, are AWESOME!</p>

Sample Modification for Twitter Bootstrap 3

Taking all the above knowledge into account, we can create a nice, highly usable and user-friendly rendering strategy using the Bootstrap front-end framework version 3 layouts:

// In any of your .phtml files:
$flash = $this->flashMessenger();
    <button type="button" class="close" data-dismiss="alert" aria-hidden="true">

echo $flash->render('error',   array('alert', 'alert-dismissible', 'alert-danger'));
echo $flash->render('info',    array('alert', 'alert-dismissible', 'alert-info'));
echo $flash->render('default', array('alert', 'alert-dismissible', 'alert-warning'));
echo $flash->render('success', array('alert', 'alert-dismissible', 'alert-success'));

The output of the above example would create dismissable FlashMessages with the following HTML markup. The example only covers one type of FlashMessenger output; if you would have several FlashMessages available in each of the rendered namespaces, then you would receive the same output multiple times only having different CSS classes applied.

<div class="alert alert-dismissable alert-success">
    <button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button>
        <li>Some FlashMessenger Content</li>
        <li>You, who's reading the docs, are AWESOME!</li>

Alternative Configuration of the ViewHelper Layout

Zend\View\Helper\Service\FlashMessengerFactory checks the application configuration, making it possible to set up the FlashMessenger strings through your module.config.php, too. The next example will set up the output to be identical with the above Twitter Bootstrap 3 Example

'view_helper_config' => [
    'flashmessenger' => [
        'message_open_format'      => '<div%s><button type="button" class="close"
data-dismiss="alert" aria-hidden="true">&times;</button><ul><li>',
        'message_close_string'     => '</li></ul></div>',
        'message_separator_string' => '</li><li>',