WEBVTT NOTE Created by CaptionSync from Automatic Sync Technologies www.automaticsync.com 00:00:00.996 --> 00:00:03.526 align:middle I see Symfony as two big parts. 00:00:03.976 --> 00:00:08.076 align:middle The first half is the route, controller, response system. 00:00:08.566 --> 00:00:10.816 align:middle It's dead simple and well... 00:00:10.906 --> 00:00:12.986 align:middle you're already an expert on it! 00:00:13.546 --> 00:00:19.936 align:middle The second half of Symfony is all about the many useful objects that are floating around... 00:00:20.176 --> 00:00:22.096 align:middle just waiting for us to use them! 00:00:22.606 --> 00:00:28.466 align:middle For example, when we render a template, what we are actually doing is taking advantage 00:00:28.466 --> 00:00:32.336 align:middle of a Twig object and asking it to render a template. 00:00:33.096 --> 00:00:38.206 align:middle There's also a logger object, a cache object, a database connection object, 00:00:38.476 --> 00:00:43.056 align:middle an object that helps make API requests, and many, many more! 00:00:43.576 --> 00:00:49.016 align:middle And when you install a new bundle, that give you even more useful objects. 00:00:49.676 --> 00:00:53.506 align:middle The truth is that everything that Symfony does is... 00:00:53.506 --> 00:00:56.516 align:middle actually done by one of these useful objects. 00:00:56.706 --> 00:01:00.496 align:middle Heck there's even a router object that's responsible 00:01:00.496 --> 00:01:03.356 align:middle for finding the matching route for the given page! 00:01:04.316 --> 00:01:09.936 align:middle In the Symfony world, and really the object oriented programming world in general, 00:01:10.176 --> 00:01:15.506 align:middle these "objects that do work" have a special name: services. 00:01:16.166 --> 00:01:17.766 align:middle But don't let that word confuse you. 00:01:18.186 --> 00:01:23.016 align:middle When you hear service, just think: that's an object that does work! 00:01:23.496 --> 00:01:26.316 align:middle Like a templating object that renders a template 00:01:26.576 --> 00:01:29.906 align:middle or a database connection object that makes queries. 00:01:30.506 --> 00:01:34.056 align:middle And since service objects do work, they're basically... 00:01:34.206 --> 00:01:36.936 align:middle tools that help you get your job done! 00:01:37.756 --> 00:01:41.356 align:middle The second half of Symfony is all about discovering 00:01:41.356 --> 00:01:44.456 align:middle which services are available and how to use them. 00:01:45.346 --> 00:01:46.466 align:middle Let's try something. 00:01:47.146 --> 00:01:50.496 align:middle In our controller, I want to log a message... 00:01:50.646 --> 00:01:53.076 align:middle maybe some debugging message. 00:01:53.996 --> 00:01:58.026 align:middle Since logging a message is work, it's done by a service. 00:01:58.406 --> 00:02:01.616 align:middle Does our app already have a logger service? 00:02:02.136 --> 00:02:04.216 align:middle And if so, how do we get it? 00:02:05.316 --> 00:02:09.366 align:middle To find out, move over to your terminal and run another bin/console command: 00:02:09.706 --> 00:02:19.256 align:middle php bin/console debug:autowiring Say hello to one of the most powerful bin/console commands. 00:02:19.596 --> 00:02:20.936 align:middle I love this thing! 00:02:21.526 --> 00:02:25.186 align:middle This lists all of the services that exist in our app. 00:02:25.716 --> 00:02:28.066 align:middle Okay, it's actually not the full list, 00:02:28.546 --> 00:02:31.776 align:middle but this shows the services that you're most likely to need. 00:02:31.776 --> 00:02:35.756 align:middle And even though our app is small, there's a lot of stuff here! 00:02:36.316 --> 00:02:38.096 align:middle There's a filesystem service... 00:02:38.436 --> 00:02:40.686 align:middle and down here a cache service. 00:02:41.136 --> 00:02:43.096 align:middle There's even a twig service! 00:02:43.866 --> 00:02:45.806 align:middle Is there a service for logging? 00:02:46.486 --> 00:02:47.676 align:middle You can look in this list... 00:02:48.036 --> 00:02:52.936 align:middle or you can re-run this command and search for the word log: Excellent! 00:02:53.546 --> 00:02:56.296 align:middle For now, ignore everything except for the first line. 00:02:56.526 --> 00:03:00.026 align:middle This line tells us that there is a logger service 00:03:00.406 --> 00:03:06.346 align:middle and that this object implements an interface called Psr\Log\LoggerInterface. 00:03:07.366 --> 00:03:10.726 align:middle Ok, so why does knowing that help us? 00:03:11.546 --> 00:03:18.626 align:middle Because if you want a service, you ask for it by using the type-hint shown in this command. 00:03:19.096 --> 00:03:20.936 align:middle It's called autowiring. 00:03:21.806 --> 00:03:22.326 align:middle Let's try it. 00:03:22.736 --> 00:03:26.066 align:middle Head over to our controller and add a second argument. 00:03:26.516 --> 00:03:29.576 align:middle Actually, the order of these arguments doesn't matter. 00:03:30.046 --> 00:03:35.756 align:middle What matters is that the new argument is type-hinted with LoggerInterface. 00:03:36.266 --> 00:03:38.336 align:middle I'll hit tab to autocomplete that... 00:03:38.676 --> 00:03:42.366 align:middle so that PhpStorm adds the use statement on top. 00:03:42.366 --> 00:03:47.096 align:middle In this case, the argument can be called anything, like $logger. 00:03:47.866 --> 00:03:52.876 align:middle When Symfony sees this type-hint, it looks inside of the debug:autowiring list... 00:03:53.296 --> 00:03:57.626 align:middle and because there's a match, it will pass us the logger service. 00:03:58.276 --> 00:04:03.456 align:middle So we now know two different types of arguments that we are allowed to have in controller: 00:04:04.226 --> 00:04:08.446 align:middle you can have an argument whose name matches a wildcard in the route 00:04:08.756 --> 00:04:13.796 align:middle or an argument whose type-hint matches one of the services in our app. 00:04:14.876 --> 00:04:20.786 align:middle Ok, so now that we know Symfony will pass us the logger service object, let's use it! 00:04:21.126 --> 00:04:24.906 align:middle I don't know, yet, what methods I can call on it but... 00:04:24.906 --> 00:04:26.536 align:middle if we say $logger->... 00:04:27.046 --> 00:04:28.226 align:middle PhpStorm... 00:04:28.226 --> 00:04:30.056 align:middle tells us! That was easy! 00:04:30.976 --> 00:04:34.236 align:middle I'm going to log something at an info() priority level. 00:04:34.776 --> 00:04:39.276 align:middle Let's say: Returning API response for song And then the $id. 00:04:41.346 --> 00:04:45.276 align:middle Actually, we can do something even cooler with this logger service. 00:04:46.406 --> 00:04:49.046 align:middle Add {song} to the message... 00:04:49.466 --> 00:04:52.726 align:middle and add a second argument, which is an array 00:04:52.726 --> 00:04:56.216 align:middle of extra information you want to attach to the log message. 00:04:57.036 --> 00:04:59.376 align:middle Pass song set to $id. 00:05:01.136 --> 00:05:07.196 align:middle In a minute, you'll see that the logger will print the actual id in place of {song}. 00:05:08.756 --> 00:05:12.196 align:middle Anyways, this controller is for our API endpoint. 00:05:12.686 --> 00:05:15.966 align:middle So let's go over and refresh. 00:05:16.966 --> 00:05:20.746 align:middle Um... ok! So no error, that's good! 00:05:21.176 --> 00:05:22.536 align:middle But did it work? 00:05:23.236 --> 00:05:24.596 align:middle Where does the logger service... 00:05:24.896 --> 00:05:26.436 align:middle actually log to? 00:05:27.276 --> 00:05:33.246 align:middle Let's find out next, learn a trick to see the profiler even for API requests 00:05:33.506 --> 00:05:36.786 align:middle and then leverage our second service directly.