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We know that services do work, and we know that
Symfony is full of services that we can use.

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If you run: php bin/console debug:autowiring
We get the dinner menu of services,

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where you can order any of these
by adding an argument type-hinted

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with the matching class or interface.

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We, of course, also do work in our code...

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hopefully.

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Right now, all that work is being done inside
our controller, like creating the Starship data.

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Sure, this is hard-coded right now, but imagine

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if this were real work: like
a complex database query.

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Putting the logic inside a controller is "ok"...

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but what if we wanted to reuse
this code somewhere else?

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What if, on our homepage, we
wanted to get a dynamic count

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of the Starships by grabbing this same data?

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To do that, we need to move
this "work" into its own service

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that both controllers could then use.

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In the src/ directory, create
a new Repository directory

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and a new PHP class inside
called StarshipRepository.

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Just like when we built our Starship class,

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this new class has absolutely
nothing to do with Symfony.

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It's just a class that we've decided
to create to organize our work.

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And so, Symfony doesn't care what it's
called, where it lives or what it looks like.

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I called it StarshipRepository and
put it in a Repository directory

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because that's a common programming
name for a class whose "work" is

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to fetch a type of data, like Starship data.

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Ok, before we even do anything in here, let's
see if we can use this inside a controller.

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And, good news!

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Just by creating this class, it's
already available for autowiring.

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Add a StarshipRepository $repository argument,
and, to make sure it's working, dd($repository).

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All right, spin over, click
back to our endpoint, and...

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got it. That's so cool!

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Symfony saw the StarshipRepository type-hint,
instantiated that object, then passed it to us.

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Delete the dd()...

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and let's move the starship data inside.

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Copy it...

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and create a new public function
called, how about, findAll().

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Inside, return, then paste.

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Back over in StarshipApiController,
delete that...

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and it's beautifully simple:
$starships = $repository->findAll().

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Done! When we try it, it still works...

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and now the code for fetching
starships is nicely organized

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into its own class and reusable across our app.

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With that victory under our belt,
let's doing something harder.

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What if, from inside StarshipRepository,

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we needed access to another
service to help us do our work?

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No problem!

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We can use autowiring!

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Let's try to autowire the logger service again.

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The only difference this time is that we're
not going to add the argument to findAll().

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I'll explain why in a minute.

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Instead, add a new public function __construct()

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and do the auto-wiring there:
private LoggerInterface $logger.

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Down below, to use it, copy the code
from our controller, delete that,

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paste it here, and update it to $this->logger.

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Cool! Over in the controller, we can remove that
argument because we're not using it anymore.

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Testing time!

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Refresh! No error - that's a good sign.

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To see if it logged something, go to /_profiler,
click on the top request, Logs, and...

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there it is!

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So let me explain why we added the
service argument to the constructor.

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If we want to fetch a service - like the
logger, a database connection, whatever,

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this is the correct way to use autowiring: add
a __construct method inside another service.

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The trick we saw earlier - where we add
the argument to a normal method - yeah,

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that's special and only works
for controller methods.

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It's an extra convenience
that was added to the system.

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It's a great feature, but the constructor way...

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that's how autowiring really works.

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And this "normal" way, it
even works in a controller.

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You could add a __construct() method

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with an autowirable argument
and that would totally work.

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The point is: if you are in
a controller method, sure,

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add the argument to the method - it's nice!

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Just remember that it's a special
thing that only works here.

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Everywhere else, autowire
through the constructor.

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Let's celebrate our new service
by using it on the homepage.

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Open up MainController.

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This hardcoded $starshipCount
is so 30 minutes ago.

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Autowire StarshipRepository $starshipRepository,

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then say $ships = $starshipRepository->findAll()
and count them with count().

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While we're here, instead of
this hardcoded $myShip array,

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let's grab a random Starship object.

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We can do that by saying $myShip equals
$ships[array_rand($ships)] Let's try it!

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Hunt down your browser and head to the homepage.

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Got it! We see the randomly changing ship down
here, and the correct ship number up here...

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because we're multiplying
it by 10 in the template.

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And something crazy-cool just happened!

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A minute ago, myShip was an associative array.

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But we changed it to be a Starship object.

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And yet, the code on our page kept working.

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We just accidentally saw a superpower of Twig.

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Head to templates/main/homepage.html.twig
and scroll down to the bottom.

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When you say myShip.name, Twig is really smart.

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If myShip is an associative
array, it'll grab the name key.

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If myShip is an object, like it is
now, it will grab the name property.

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But even more than that,
if you look at Starship,

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the name property is private,
so we can't access it directly.

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Twig realizes that.

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It looks at the name property,
sees that it's private,

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but also sees that there's a public getName().

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And so, it calls that.

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All we need to say is myShip.name...

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and Twig handles the details of
how to fetch that, which I love.

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Ok, one last tiny tweak.

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Instead of passing the starshipCount into our
template, we can do the count inside Twig.

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Delete this variable, and
instead, pass a ships variable.

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In the template, there we go, for the
count, we can say ships, which is an array,

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and then use a Twig filter: |length.

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That feels good.

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Let's do the same thing down here...

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and change it to greater than 2.

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Try that out.

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Our site just keeps working!

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Next up: let's create more pages and learn
how to make routes that are even smarter.