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Save, Redirect, setFlash (and Dance)

We already have the finished Genus object. So what do we do now? Whatever we want!

Probably... we want to save this to the database. Add $genus = $form->getData(). Get the entity manager with $em = this->getDoctrine()->getManager(). Then, the classic $em->persist($genus) and $em->flush():

52 lines src/AppBundle/Controller/Admin/GenusAdminController.php
... lines 1 - 12
class GenusAdminController extends Controller
{
... lines 15 - 31
public function newAction(Request $request)
{
... lines 34 - 37
if ($form->isSubmitted() && $form->isValid()) {
$genus = $form->getData();
$em = $this->getDoctrine()->getManager();
$em->persist($genus);
$em->flush();
... lines 44 - 45
}
... lines 47 - 50
}
}

Always Redirect!

Next, we always redirect after a successful form submit - ya know, to make sure that the user can't just refresh and re-post that data. That'd be lame.

To do that, return $this->redirectToRoute(). Hmm, generate a URL to the admin_genus_list route - that's the main admin page I created before the course:

52 lines src/AppBundle/Controller/Admin/GenusAdminController.php
... lines 1 - 12
class GenusAdminController extends Controller
{
... lines 15 - 31
public function newAction(Request $request)
{
... lines 34 - 37
if ($form->isSubmitted() && $form->isValid()) {
... lines 39 - 44
return $this->redirectToRoute('admin_genus_list');
}
... lines 47 - 50
}
}

Because redirectToRoute() returns a RedirectResponse, we're done!

Time to try it out. I'll be lazy and refresh the POST. We should get a brand new "Sea Monster" genus. There it is! Awesome!

Adding a Super Friendly (Flash) Message

Now, it worked... but it lack some spirit! There was no "Success! You're amazing! You created a new genus!" message.

And I want to build a friendly site, so let's add that message. Back in newAction(), add some code right before the redirect: $this->addFlash('success') - you'll see where that key is used in a minute - then Genus created - you are amazing!:

54 lines src/AppBundle/Controller/Admin/GenusAdminController.php
... lines 1 - 12
class GenusAdminController extends Controller
{
... lines 15 - 31
public function newAction(Request $request)
{
... lines 34 - 37
if ($form->isSubmitted() && $form->isValid()) {
... lines 39 - 44
$this->addFlash('success', 'Genus created!');
return $this->redirectToRoute('admin_genus_list');
}
... lines 49 - 52
}
}

It's good to encourage users.

But let's be curious and see what this does behind the scenes. Hold command and click into the addFlash() method:

398 lines vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Controller/Controller.php
... lines 1 - 38
abstract class Controller implements ContainerAwareInterface
{
... lines 41 - 102
/**
* Adds a flash message to the current session for type.
*
* @param string $type The type
* @param string $message The message
*
* @throws \LogicException
*/
protected function addFlash($type, $message)
{
if (!$this->container->has('session')) {
throw new \LogicException('You can not use the addFlash method if sessions are disabled.');
}
$this->container->get('session')->getFlashBag()->add($type, $message);
}
... lines 119 - 396
}

Okay, cool: it uses the session service, fetches something called a "flash bag" and adds our message to it. So the flash bag is a special part of this session where you can store messages that will automatically disappear after one redirect. If we store a message here and then redirect, on the next page, we can read those messages from the flash bag, and print them on the page. And because the message automatically disappears after one redirect, we won't accidentally show it to the user more than once.

And actually, it's even a little bit cooler than that. A message will actually stay in the flash bag until you ask for it. Then it's removed. This is good because if you - for some reason - redirect twice before rendering the message, no problem! It'll stay in there and wait for you.

Rendering the Flash Message

All we need to do now is render the flash message. And the best place for this is in your base template. Because then, you can set a flash message, redirect to any other page, and it'll always show up.

Right above the body block, add for msg in app.session - the shortcut to get the session service - .flashbag.get() and then the success key. Add the endfor:

49 lines app/Resources/views/base.html.twig
<!DOCTYPE html>
<html>
... lines 3 - 13
<body>
... lines 15 - 28
<div class="main-content">
{% for msg in app.session.flashBag.get('success') %}
... lines 31 - 33
{% endfor %}
... lines 35 - 36
</div>
... lines 38 - 46
</body>
</html>

Why success? Because that's what we used in the controller - but this string is arbitrary:

54 lines src/AppBundle/Controller/Admin/GenusAdminController.php
... lines 1 - 12
class GenusAdminController extends Controller
{
... lines 15 - 31
public function newAction(Request $request)
{
... lines 34 - 37
if ($form->isSubmitted() && $form->isValid()) {
... lines 39 - 44
$this->addFlash('success', 'Genus created!');
... lines 46 - 47
}
... lines 49 - 52
}
}

Usually I have one for success that I style green and happy, and on called error that style to be red and scary.

I'll make this happy with the alert-success from bootstrap and then render msg:

49 lines app/Resources/views/base.html.twig
<!DOCTYPE html>
<html>
... lines 3 - 13
<body>
... lines 15 - 28
<div class="main-content">
{% for msg in app.session.flashBag.get('success') %}
<div class="alert alert-success">
{{ msg }}
</div>
{% endfor %}
... lines 35 - 36
</div>
... lines 38 - 46
</body>
</html>

Cool! Go back and create Sea Monster2. Change its subfamily, give it a species count and save that sea creature! Ocean conservation has never been so easy.

And, I'm feeling the warm and fuzzy from our message.

Next, let's really start to control how the fields are rendered.

Leave a comment!

  • 2016-11-14 Terry Caliendo

    Got it. Thanks.

  • 2016-11-13 weaverryan

    Very astute Terry! That's exactly it: each "key" in the flash bag is actually an array that can hold many values. Most of the time, you don't need this, but it's built with that flexibility. The only time I've ever relied on this is a few times when I've used the flash bag to send custom analytic information. When the user takes an action, I would record it in a special place on the flashbag. Then, the next time a full HTML page was loaded, we would read those flash messages and render some custom JS to send that info to the analytics service. In this case, it was possible that the user would take *multiple* actions, before the next full page load... and that was totally fine :).

    Cheers!

  • 2016-11-12 Terry Caliendo

    Towards the end you you do a for loop on the flashbag in twig on the "success". Does this mean you can have multiple calls in your controller to submit to the same "success" key without overwriting the last?