WEBVTT 00:00.000 --> 00:00.300 Okay. 00:00.300 --> 00:01.590 Welcome to section two. 00:01.590 --> 00:06.510 And in this section we're going to take a look at some API basics and really start getting our hands 00:06.510 --> 00:11.670 dirty with building this application or at least the beginnings of our application. 00:11.670 --> 00:14.910 So coming up in this particular section what we're going to take a look at. 00:14.940 --> 00:17.280 We're going to take a brief look at what is net. 00:17.310 --> 00:22.650 It's this all encompassing framework that's designed to help us build any type of application. 00:22.650 --> 00:24.750 So we'll take a closer look at that. 00:24.780 --> 00:30.270 We're also going to take a look at what we are building, which is going to be a Rest based API, an 00:30.270 --> 00:35.910 application programming interface that allows our client, our react client, that we're going to build 00:35.910 --> 00:42.240 on the front end to make a query to our back end in the dotnet world and retrieve data from a database 00:42.240 --> 00:44.460 and return it to that client. 00:44.640 --> 00:50.280 In order to create our project, we're going to make use of the dotnet command line interface, which 00:50.280 --> 00:54.810 gives us a bunch of different commands that we can use to do various dotnet related things. 00:54.810 --> 01:02.420 One of them to be to create a template for a web API type of project that we'll be using On our back 01:02.450 --> 01:03.290 end. 01:03.500 --> 01:08.780 Once we have our projects, we're going to take a closer look at it and see what's involved inside that 01:08.780 --> 01:12.080 project and how we start and stop and run our. 01:12.290 --> 01:13.850 Net application. 01:13.880 --> 01:16.550 Following that, we're going to take a look at Entity Framework. 01:16.550 --> 01:18.260 We need a database for our application. 01:18.260 --> 01:19.880 It's going to be database driven. 01:19.880 --> 01:24.110 And we're going to use Entity Framework to help us query our database. 01:24.110 --> 01:28.550 And the database that we're going to use just for development is SQLite. 01:28.940 --> 01:34.490 So please don't worry if you're thinking or a red flag is being raised thinking, well, we can't use 01:34.490 --> 01:40.220 SQLite for production applications, I know, but it is useful for development as I'll explain as we 01:40.220 --> 01:41.030 go along. 01:41.060 --> 01:47.060 And then once we reach certain milestones, we'll save our hard work into source control using git, 01:47.060 --> 01:50.150 which hopefully you have installed on your computer now. 01:50.150 --> 01:55.640 And we'll also save our code into a public repository on the internet called GitHub. 01:55.640 --> 02:01.100 So even if the worst happens, we lose our hard drive, we lose our computer, then our code is still 02:01.100 --> 02:07.320 safe out there on the internet that we can use and clone onto a new computer as and when we choose to 02:07.350 --> 02:08.160 do so. 02:08.190 --> 02:10.230 So what is net? 02:10.260 --> 02:17.220 Well, it's a framework that allows us to build any conceivable type of app that you can think of. 02:17.340 --> 02:22.710 We can build a web application, mobile apps, desktop apps, cloud based apps, artificial intelligence 02:22.710 --> 02:24.360 based apps, and machine learning. 02:24.390 --> 02:25.530 We can build games. 02:25.530 --> 02:31.470 We can build things that run inside fridges, in the internet of things, and really just about anything 02:31.470 --> 02:34.170 that you can conceive, you could technically use. 02:34.350 --> 02:35.430 Net to do so. 02:35.460 --> 02:38.340 So it's big, it is very big. 02:38.340 --> 02:43.230 And we're not going to scratch the surface really of the entire framework. 02:43.230 --> 02:45.540 We're going to use it for a very specific task. 02:45.540 --> 02:47.010 And what is that task. 02:47.010 --> 02:48.360 What are we using it for. 02:48.390 --> 02:49.890 Well it's to build an API. 02:49.920 --> 02:53.010 Now this is taken directly from Microsoft documentation. 02:53.010 --> 02:57.180 And it's got some terms on here that look a bit weird really. 02:57.210 --> 02:59.970 Things like ASP. 03:00.750 --> 03:01.350 Net. 03:01.380 --> 03:04.290 What is that and what's core. 03:04.320 --> 03:06.930 Because I've said that we're using dot net. 03:06.960 --> 03:09.960 Are these the same things or are they different in some way? 03:09.990 --> 03:15.480 Well, Microsoft traditionally are terrible at naming things and dot net. 03:15.510 --> 03:18.690 The current iteration that we're using is really. 03:18.930 --> 03:21.540 Net core that's had a rebranding. 03:21.840 --> 03:24.750 So once upon a time in the windows world there used to be the. 03:24.930 --> 03:27.810 Net framework that would only run on windows machines. 03:27.840 --> 03:32.340 Microsoft a few years back decided to rewrite the whole thing, call it. 03:32.490 --> 03:35.940 Net core, and make it cross-platform and open source. 03:35.940 --> 03:40.020 And that's what everyone uses nowadays, and they've effectively discontinued the original. 03:40.200 --> 03:41.310 Net framework. 03:41.340 --> 03:44.250 So to avoid confusion, they removed the dot. 03:44.580 --> 03:48.870 Net core label and just referred to it as dot net. 03:49.560 --> 03:54.570 So what we still have though, in documentation, in the code that we use sometimes we're still referring 03:54.600 --> 03:55.800 to things called ASP. 03:55.830 --> 04:02.070 Net and ASP stands for Active Server Pages, which is a really old technology for building functional 04:02.070 --> 04:07.940 web pages that's no longer in existence, but the name has been retained. 04:07.940 --> 04:15.740 And you'll typically see ASP when we're using web related parts of the framework that's designed to 04:15.770 --> 04:18.170 help us build web based applications. 04:18.170 --> 04:20.270 So we'll still see things like ASP. 04:20.300 --> 04:26.240 We'll still see things like core when we're writing our code with the packages that we use from. 04:26.450 --> 04:31.190 Net so just something to be aware of, but nothing to be concerned about. 04:31.190 --> 04:33.740 And when it comes to net, I'll just briefly mention. 04:33.920 --> 04:34.730 Net versions. 04:34.730 --> 04:36.620 Currently we're on version nine. 04:36.620 --> 04:41.300 I'm recording this in late 2024, so the current version available is. 04:41.450 --> 04:45.680 Net nine, but Microsoft typically release a major version every November. 04:45.680 --> 04:47.090 So next November it's going to be. 04:47.240 --> 04:49.970 Net ten following that, net 11. 04:49.970 --> 04:52.130 And so on and so forth. 04:52.730 --> 04:59.120 And the even numbered versions of Net these are the ones that are considered long term support, which 04:59.120 --> 05:05.620 means these are supported with stability bug fixes, security updates for three years after its initial 05:05.620 --> 05:06.310 release. 05:06.310 --> 05:11.920 When it comes to the standard releases like Net nine and Net 11, these are supported for 18 months. 05:11.980 --> 05:15.670 What this means in practice is for production based applications. 05:15.670 --> 05:19.030 Then typically you would skip the odd numbered version. 05:19.030 --> 05:25.180 The odd numbered versions are used for new features, typically, and the even numbered ones are more 05:25.180 --> 05:28.210 stability versions that have that long term support. 05:29.110 --> 05:34.360 So for a production application, you're typically not upgraded to Net nine, but you would wait till 05:34.510 --> 05:35.050 Net ten. 05:35.050 --> 05:39.550 So you're really you're looking at a two year cycle for upgrading between Net versions. 05:39.550 --> 05:41.650 We're going to go through Net nine because why not. 05:41.680 --> 05:42.580 It's a training course. 05:42.580 --> 05:46.960 And the application we're building is just a demo application. 05:46.960 --> 05:52.630 It's not going to live and service normal users because we're selling fake products in a store that 05:52.630 --> 05:54.100 doesn't actually exist. 05:54.100 --> 05:54.940 So we're going to use. 05:55.090 --> 05:58.540 Net nine or at least that's what this course is aiming at. 05:58.630 --> 06:02.440 The net ecosystem is made up of many different parts. 06:02.440 --> 06:03.460 We have our languages. 06:03.460 --> 06:05.770 What language do we write our code in? 06:05.770 --> 06:11.360 Well, there's options because we can use C sharp, we can use F sharp and Visual Basic. 06:11.360 --> 06:18.140 And the most commonly used language of these is C sharp, which is an object orientated language that 06:18.140 --> 06:21.230 also supports functional programming. 06:22.160 --> 06:24.800 And it's the most general purpose of the three of them. 06:24.830 --> 06:30.410 F sharp is a functional first programming language and is good for data processing type applications. 06:30.410 --> 06:34.370 Heavy financial math, heavy scientific type applications. 06:34.370 --> 06:36.650 Not something that we're building on this training course. 06:36.650 --> 06:39.380 And Visual Basic is really kind of legacy. 06:39.410 --> 06:46.010 It was geared towards simplicity and readability and was often preferred by developers with a background 06:46.010 --> 06:49.970 in Visual Basic, and that's really retained for legacy purposes. 06:50.240 --> 06:55.040 But since we have different languages, then we have different runtimes that handle those different 06:55.040 --> 06:57.770 languages and the features specific to those languages. 06:57.770 --> 07:03.290 But obviously when it's outputs, it needs to be output into a language our machine can understand. 07:03.320 --> 07:08.030 And we also have the Common Language Runtime that takes care of that. 07:08.720 --> 07:13.400 So whatever language we write our code in, there's something that's going to compile it into something 07:13.400 --> 07:17.060 the machine can understand at the end of it, but we still just use the single. 07:17.240 --> 07:18.920 Net framework to do so. 07:18.980 --> 07:22.250 We also have libraries that come along with dotnet. 07:22.370 --> 07:27.170 DotNet is a framework and there's many libraries encompassed inside that framework. 07:27.170 --> 07:29.690 So there's libraries for things like authentication. 07:29.690 --> 07:32.810 There's libraries for things like forms and HTTP requests. 07:32.810 --> 07:35.690 And it's really such a huge framework. 07:35.690 --> 07:38.210 It's made up of many, many different libraries. 07:38.210 --> 07:40.160 But even that may not be enough. 07:40.160 --> 07:42.560 And we need to get third party library support. 07:42.560 --> 07:47.810 And in which case we can rely on NuGet, which is the package manager for DotNet, which will allow 07:47.810 --> 07:53.390 us to install additional packages not provided by the framework into our application. 07:53.390 --> 07:57.350 And we also have the dotnet command line interface which helps us manage. 07:57.560 --> 07:59.060 Net from a command line. 07:59.060 --> 08:05.870 And for our training course purposes, we're going to be using C-sharp to build our application. 08:06.080 --> 08:10.230 And there could even be a strong argument for saying, well, if you're only going to learn one thing, 08:10.230 --> 08:15.420 then C sharp is a very versatile language, and it is relatively easy to learn because of its strong 08:15.420 --> 08:17.730 support for objects and type safety. 08:17.910 --> 08:21.960 So we're going to be building a web API using C sharp and the. 08:22.170 --> 08:24.540 Net and what is a web API? 08:24.570 --> 08:30.810 Well, it's effectively in our use case HTTP services that are going to be running on top of. 08:30.990 --> 08:37.950 Net and we're going to create things called API controllers that have API endpoints, whose job is to 08:37.980 --> 08:45.420 receive HTTP requests from our client and send back HTTP responses, including the data that we retrieve 08:45.420 --> 08:46.920 from our database. 08:46.920 --> 08:53.340 And to build this API, we're going to be using Rest based protocols, which is really a set of constraints 08:53.340 --> 08:56.280 about how we go about building our API. 08:56.280 --> 09:00.510 And Rest stands for Representational State Transfer. 09:00.540 --> 09:05.070 You'll often hear that mentioned in the same breath as building a web API. 09:05.070 --> 09:10.630 It's really just a set of constraints that we use as developers to provide our API with predictability 09:10.630 --> 09:15.340 and consistency in how we build it and how it's consumed from the client. 09:15.790 --> 09:22.060 So an API, then, if we take our average user, is going to make a request to go and get our web page. 09:22.060 --> 09:28.240 And our web page is going to be a data driven web page made up of, for example, a bunch of products. 09:28.240 --> 09:32.380 But those products don't come down with the HTML that we send back to the client. 09:32.380 --> 09:38.920 They have to be retrieved by the browser, and the browser separately, will go out to our API and make 09:38.950 --> 09:45.160 a request to go and get that data, and it will make an HTTP request. 09:45.190 --> 09:52.600 Our API will receive that request and it will return an HTTP response with hopefully the list of products. 09:52.600 --> 09:58.630 And then our browser can use that list of products depending on the code we write in our react application 09:58.630 --> 10:00.250 to update the user interface. 10:00.250 --> 10:01.030 So that's our goal. 10:01.030 --> 10:07.450 And our purpose in this section is to set up the structure of our application to be able to do such 10:07.480 --> 10:08.410 a thing. 10:08.410 --> 10:10.030 So let's begin.