Learn Microservices with . Net Core

1. Introduction: Hi, Welcome to this Microservices course with ASP.net Core. My name is S1 and I'll be leading you through this course. I'm a software engineer and Microsoft most valuable professional. I designed this course so that you can learn microservices from absolute beginning. In this course, we will not use any copy paste technique. In fact, we will cover everything from scratch. But in order to take this course, you must have a knowledge of ASP.net Core RESTful APIs. Well, three to six months of rest API knowledge is enough to start this course. By the end of this course, you'll be able to dilute the micro-services of local desktop application. Alright, so what are you waiting for? Take this course and let's start learning. 2. Prerequisites: Before starting this course, just make sure to download the video studio 2022 community edition. If you're using some other edition of video studio like professional or enterprise, which supports dot and core, then it's okay. We'll Studio Community Edition is free of cost. If you can't afford the enterprise or some other edition, then just go ahead with that community edition. I have attached a download link of film studio so that you can download and install it in your machine accordingly. I also want to tell you that in this course, I'll use the shortened version six. Make sure you're using the latest version of dotnet. In order to complete this course, you must have a three to six months of experience with dotnet Core RESTful APIs. If you are an absolute beginner, that I will recommend you to please pause this course and just go to my rest API, a beginner course, where you will learn the rest API development from scratch. And right after the rest APA course, you can take this microservice course. Alright, that's all I want to talk about. I hope you are on the same page. Now let's start learning. 3. Course Structure: In this course, you learned micro-services from absolute beginning. So let me show you what is coming up over the next few sections. In the next section, we'll start out with the basics like what is microservices and how microservices works. Then we'll set up the projects for microservices. Right after that. We'll create a microservice for vehicles. Then we'll create the micro service for customers. And right after that customers microservice will cover the Azure Service Bus for communicating the microservice. In this section, we'll send the data to the Azure Service Bus. Then we'll create the reservations microservice. And right after that will fetch the data from Azure Service Bus queue. Once we will cover these things, then we will also cover the API Gateway with dotted curve using microservices. So these are the things which we'll cover in this course. All right? The time is very short and there are a lot of things to cover. So I will see you in the next section. 4. Monolithic Architecture: Before talking about the microservices architecture, we first need to understand the monolithic architecture. A monolithic application is built as a single unit. Let's take a simple example. Suppose you have been asked to create a vehicle test drive application. In this scenario, our application will consist of three parts. The database, which consists of one or more than one table with some relations. The client side user interface, which consists of HTML pages, are some user interface which will be used on the client side. The server side application, which will handle all the HTTP requests, execute the domain specific logic, retrieve, update and delete the data from the database, and populate the data to the client side application so that the client can view the data. So that's our monolith architecture works. In monolith architecture, all the components are interconnected. If we want to change anything in some particular service, then we need to redeploy the whole application because all the things are interconnected and dependent. Changing, wanting in the code will break the entire application. And to be honest, this is really annoying if you're making some enterprise level application. So to overcome this problem, we need microservices. And in the next lesson, we'll discuss the microservice architecture. I'll see you in the next one. 6. Microservices Communication: In the last lesson, we have talked about the microservice architecture. Now let me tell you how we'll perform that communication between the microservices and simple monolithic application. We have tables and relations and to services can talk to each other with the help of relations because these services share the same database. Now, in case of microservices, each service contains its own data store. How is it possible to communicate with other microservice? Well, there are multiple ways where one microservice can talk to other microservice. But first, let's take an example. Suppose we have a simple e-commerce application with some services like customers, products, basket, inventory, payments, orders, and email. The customer will add the product in the shopping cart or basket, and then he will decide how much products he will need. Let's say the customer wants to add five products in the basket. But there are only two products available for this basket service with dark to the inventory service via HTTP calls, rest APIs. This communication is internal microservice communication. Now once the customer will make the payment, then he will place the order. The customer placed the order, but the order is still pending. And from the backend, the admin after application will check whether the payment is successful or not. If the payment is successful, then the admin will send the e-mail to the customer that the order has been placed successfully. And this process is asynchronous because once the customer will place the order than the order data will go to some external service provider like Azure messaging or Rabbit MQ. And these are message brokers. Now let me tell you what is message broker. A message broker is a software that enables the applications, systems, and services to communicate with each other and exchange information. Okay, what happens here is when the customer will place the order, then the data will go to the message broker. Or in short, we will send the data to the message broker. On the other hand, the evil service will interact with the message broker, will get the order details from this message broker. And if the payment is successful, then this e-mail service will send an e-mail to the customer. The order has been placed successfully. This type of communication, which happens with message broker, is an external microservice communication or asynchronous communication. The other type of communication which we have discussed earlier is asynchronous communication or internal microservice communication. Because without knowing the inventory items left, we can't increase the items in the basket. Okay, That's all from this lesson. Now, I'll see you in the next one. 7. When To Use Microservices: In this lesson, we'll talk when we should use microservices and when we should not use the microservices. But before this, let's compare the microservices monolithic application. Now let's talk about the deployment. Deploy the monolithic application. You have to publish or redeploy the whole application. But in case of microservices, you can deploy this microservice. Then you can also deploy the other micro-services. If we'll talk about the scalability, then it's much easier to scale the microservice application. Now let's talk about the platform dependent feature. The simple monolithic applications are platform dependent. It means if we have created this first service in dotnet core and MS SQL database, then we also need to create the other services in the same language. But in case of microservices is not the case. You can get this first service in dominant core. And with Microsoft SQL database. Then you can get the other services in some other programming language. And you can also use some other database providers like MongoDB or MySQL, etc. But working on microservices will also increase the development speed. Because in enterprise applications, each developer is associated with some particular service. And it means there are less chances of errors. Highlight in monolithic application $1 per asteroid, the whole code. The developer can face many errors and it will reduce the coding speed as well. Okay, so enough talk about the monolithic and microservice applications. Now let's talk about the important part that when we should use microservices and then we should not use microservices. If your application is simple, an intermediate, like a normal cinema ticket booking. And if you're not comfortable with different programming languages and development environment, then you don't need to write the microservices. You can continue with a simple model architecture. But if your application is very complex, like e-commerce activation, right? Booking, flight, reservation, and applications like Netflix. You should probably think about microservices. So, So the choice is totally up to you. There are a hundreds of advantages and disadvantages of using microservices. But in this course, our focus is entirely on microservices because it's a market demand to learn new things. Okay, That's all from this lesson. Now, I'll see you in the next section. 8. What Microservices we will create: In this course, we'll create the microservices for local disk drives activation. Let's assume that there is some famous automobile company like Tesla. And people like me want to test drive of some particular vehicle. So we'll create a microservices for vehicle desktop application. And I know that application is quite small, but this will give you a perfect Jumpstart in the world of microservices. Okay, let me tell you the basic flow of this application. We'll create three microservices. The first will be used to handle the lifecycles data. The second issue is to handle the customers data, and the third is used to handle the reservations data. Now let's say there is some mobile or web application where we'll consume these microservices. So first of all, we'll display the vehicles list data. And this data will come from the vehicle microservice. And after selecting some vehicle, will get further details of the vehicle. Now when we press the book desktop option than we have been asked to provide the details. And once we provide these details, then this data goes to the customers microservice. And similarly, this data will also go to the Azure messaging service. Now, there is also an admin side of the aggregation. With the admin can add, update and delete the Lakers. And the admin can also send the e-mails to those customers who are interested in the desktop of the company vehicles. So when the admin will open the application and click the reservation option, then you will see the list of customers who are interested to test some particular vehicle drive. And this data will come from Azure messaging service bus, okay, then the admin can send that email to these customers for confirmation. So we'll get these microservices inside this course. Okay, let's start from the next lesson. 9. Create Solution For Microservices: In this lesson, we're going to create the solution and microservices project. It's better if you will, Katie, different we'll Studio projects for microservices. But this will also consume more RAM and processing power. Instead of opening the different instance of field Studio will just open one incidence of fetal studio. And inside this will create one solution which contains all the micro service projects. Okay, Let's open the real studio. At the time of recording this course with studio 2022 is the latest version. Okay, then create a new project. Here we need to search for blank or empty solution. You'll see that this blank solution template will create an empty solution containing no projects. Alright, let's select this and click Next. Here we need to provide a name to our solution. Let's give some user-friendly name because we are making the microservices for our vehicle test drives. So we'll name this solution to local test drive space. This option. Here we go. We'll see an empty solution inside the video studio. Now, inside the solution, we're going to add two different core Web API projects. Okay, so let's right-click on the Solution. Then we'll get a new project. And inside the search bar, we're going to search for dotnet Core. Just scroll down and we'll see an ASP.net Core Web API project template. Just select this and click Next. We need to provide a name to our project. Let's name it legal API. And click Next. Here you'll see the framework I'm using, dot and six, which is the latest favorite at this time. We don't need authentication and darker. And that's why we don't need to change anything here. Alright, then make sure this enabled open API support is checked because this will add the swagger API documentation for us. Also, in doctrine six, we have an option to use the minimal APIs. In minimal APIs, we don't use controllers. We'll just add the code in the startup class. But this is somehow for beginners. So instead of using the minimal APIs, we'll choose the controller approach. So make sure you have checked this is use Controllers option, that gate this project. Okay, here we go. Our vehicle API project has been created. Now just like this vehicle API project, we'll add two more projects. So let's right-click on the Solution. Then Add New Project and choose the dotted curve map API project template. Right after that, we will name this project to customers API. Alright, let's get this project. Here we go. Now we have two projects, vehicles, API and the customers API. It's time to add the third project, which is reservations API. So we'll right-click on the Solution. Then Add New Project, choose ASP.net Core Web API template. Then we'll leave this project to reservations API. And let's create this. We have added T projects inside the solution. Now in the next lesson, we'll install the NuGet packages for microservices. I'll see you in the next lesson. 10. Install Nuget Packages: In the last lesson, we have kicked the solution and T projects for microservices. Now in this lesson, we're going to add the NuGet packages inside these micro service projects. Currently will need the NuGet packages. One is for Entity Framework Core, second is for SQL Server database connection, and the third is for Migration purpose. Okay, we need to install these two NuGet packages inside these three micro service projects. Instead of adding the packages one-by-one inside these micro-services, let's right-click on the Solution and then select Manage NuGet packages for solution. Now, inside the search bar, Let's search for Entity Framework Core NuGet package. And here I'm going to install this NuGet package inside all these projects. Okay, so let's install this NuGet package for Entity Framework Core. Here we go. The package has been installed successfully. Now let's search for other package, which is for SQL Server database. And again, we're going to install the package inside these projects. Once will install this package. Then we'll search for this package for Migration purpose, which is Microsoft dot core dot tools. And again, we're going to install this package inside all the projects. We have installed all the necessary packages. Now as we'll move forward, then we will also install other NuGet packages. But till then we have enough material to start our microservice project. So let's start writing our first micro-service in the next section. 11. Vehicle Service Overview: In this section, we're going to get the micro service for vehicles. Let me tell you the basic flow of this vehicle. Microservice, this way called micro service, will be based on five different methods. Get vehicles which will return all the lists of vehicles. Get vehicle by ID, which will return the specific vehicle detail according to the vehicle ID. Add method will be used to add them later record. Update method will be used to update the vehicle record and delete vehicle will be used to delete the vehicle, record. These two methods get vehicle and get wiggled by IDR GET methods. This ad vehicle is a post method, it is a PUT method, and this delete vehicle is a delete action method. In this course, we will not get the mobile application or web application because our focus is entirely on the micro-services. Okay, So let's start creating the vehicle microservice in the next lesson. 12. Create Models For Vehicle Service: In this lesson, we'll start getting the vehicle micro-service. First, we'll start with a model class. Before adding the mortar class, let me delete the unnecessary code like this weather forecast and this weather forecast controller class. Also delete the weather forecast and Bedford costs controller from the other two projects. Okay. Now let's get folder inside the vehicle microservice project and we name it models. Then inside this model's folder, Let's add a new C-Sharp class. And I'm going to name this class to Waco. Alright, here we go. Inside this class, Let's add some properties like idea of the vehicle, name of the vehicle, price of the vehicle, in which URL of the vehicle. Then we'll add the property for displacement of the vehicle. Right after that, we'll add the maximum speed, and we'll also add the vehicle length, width, and height properties. You can also add more properties in this vehicle class if you want. But I have added just a few properties to keep things simple. Alright? Once you add these properties inside this vehicle class, then we'll create the DB context. So let's get the DB context in the next lesson. 13. DbContext For Vehicles Service: Earlier in this course, we have created the modal class for vehicle. And now in this lesson, we're going to create the DB context class. The DB context class is an important class. It acts as a bridge between your model class and your database. And it's also responsible for converting LINQ queries into SQL queries, send them to database. What I mean is when we'll perform the crud operations with the database, then we'll use the link queries. And this DVI contexts will convert those LINQ queries into SQL queries and then send them to the database. So before adding the DB context class, Let's create a new folder and name it data. Then in this data folder, I'm going to add a new class. Then we named this class to API DB context. Let's add this class. Then we just need to derive this class from DB context. And this DB context comes from the Entity Framework Core namespace. And we have to resolve the namespace for this class. Then inside the EPA DB context class, I'm going to add one property. Let's add a property. Now the question is, what this property is going to written? Well, it's going to return the DB set of vehicle. Okay, The saltiness phase for this little glass. Then we named this property to Lakers. At the runtime Entity Framework will map this TV set property with a database table name. For example, if we name this property here as vehicles, than Entity Framework will get a table inside a database with the same name, that is vehicles. Alright, now let's provide the connection string to this DB context class. For this purpose, we'll use to our add method that is on configuring. Once we will write this on configuring method, then remove this line. And here we'll add these options builder. Then call the use sequel server method, which will take the connection string. So we'll go to the SQL Server Object Explorer. Here, we'll see the server name. Let's copy the server name. Then in the use SQL Server method will add server equals. Then add the name of the SQL Server which we copied. Right after this step, we will use database equals. And here we need to provide some user-friendly name of our database. Because we are making a microservice of vehicle. So we'll leave our database to legal API DB. Alright, now in the next lesson, we'll add the migrations to the database inside a SQL Server. So I'll see you in the next lesson. 14. Migration In Vehicle Service: In the last lesson, we have set up the connection string. And now in order to get a database, we need to add the migrations. To enable the migrations. First, we'll need a NuGet package that is Microsoft dot core dot tools. And we have already installed this NuGet package. So we'll go to the Package Manager console. And there we're going to add them migrations. But before adding the migrations, just select this project in which we are adding the migrations. For example, if you are adding the migration in vehicle microservice, then select the vehicle microservice project. In the Package Manager console, set the default project to Microservice. Similarly, when we'll add the migrations in some other project, then we need to change the default project. At this time, we want to add the migrations in the Michel's microservice. So make sure vehicle project is selected. Then in the Package Manager console, we'll add a command that is add dash migration, and then provide a user-friendly names with the migration. Hi limit, initial Create, and let's hit Enter. This will generate the migration script. This script will be used to add the database and tables, but we have not actually created the database yet. So again, in the Package Manager console, let's use the command that is update dash database, and let's hit Enter. Now this will add the database and tables inside the SQL Server Object Explorer. Let me go to the SQL Server Object Explorer. Let's refresh the server. And it will expand this server. Then we will see the database folder. It will expand this further. Then we'll see our database. Inside this will also see the table. Let's open the table. And here you'll see that inside this table we have all the properties which we have defined in the vehicle model class. Okay, so far we have added the database and the table. Now let's continue over in the next lesson. 16. Create Vehicle Service: Earlier we have worked with the interfaces and now in this lesson, begin to work with the services. Basically in the vehicle interface, we have defined these methods. And now we'll get a vehicle service in which we'll add the eye Legal Methods implementation. Let's get a new folder and rename IT services. Now inside this folder, Let's add a new C-Sharp class and rename it local service. Now inside this vehicle service, right, the implementation of methods that we have written in the vehicle interface. So let's implement this vehicle service class from a vehicle interface. Then resolve the namespace for this interface. Alright, we need to implement the methods for this by vehicle interface. And we'll use the veal Studio feature of implementing the methods. If you can't see this, then press Control period, and then implement this I vehicle interface methods. Alright, so we'll studio built-in feature will add all the methods in the vehicle service class. Now, we just need to add the logic inside these methods. First, we'll start with our vehicles method. This method will return the list of vehicles and we're going to add the logic inside this method. But first, we'll need a data source. We want to access the vehicles DB set property which we have written in the APA DB context class. So to access the DB set property, we'll add a field of type ABA DB context is all the namespace. Then we'll leave this field to DB context. Okay, right after that, we'll add a constructor. And here we'll create a new instance of API DB context and assign this to DB context. Now with this DVI contexts, we can pick the vehicles property which we have defined in the API DB context class. So we'll simply go to this Get all vehicles method. Let's start our work. This method will return the list of vehicles from the database. So we'll simply use DB context dot. Then we'll pick the vehicles D, we said property. And right after that will make this method is synchronous and use the await operator here. Now, we'll store the result in a variable intimate Lakers. Okay, you'll see the arrow here. And that's because this DB context dot vehicles within the list of records. So we need to convert this into two list. After converting this into two lists, we still get an error. And that's because these two lists will work with synchronous call. But this time we're using the asynchronous calls. So let's use to list method. Alright. This is all the namespace for these two lists, async, which comes from this Microsoft dot Entity Framework Core namespace. Let's written this vehicles. Then we'll go to another getMethod. And first of all, let's make this method Async. Then we'll use the await keyword. Right after that, we'll use DB context and pick the Lakers property. After that, let's call a helper method. That is fine. But we're using the async call. So let's use the fine async method. And inside this find async method, we need to pass this ID, this line with just certain specific vehicle against the ID, which will pass in this method. We'll store the result in a variable and name it like. Alright. Now just written this vehicle. Right after this getMethod will go to the add method. First, we'll make this method async, await keyword and choose DB context. Then pick the vehicles dividend property. And right after that, we'll call the helper method that is add async. Inside this add method, we'll pass this vehicle object. Now, this line will add the data inside the database. But we have to call the CF gene this method, because in order to perform some insert, update, and delete operations, we have to use the CF gene, this method. And because this is an AC method, so let's use CFCs async here. Then we'll go to the update method. First, we'll make this method Async, then use the await keyword. And right after that we will use DB context dot vehicles property. Now we'll call the find async and pass this ID. Basically this line will find that vehicle record inside a database against this ID. Okay, let's store the result in a variable and rename it like an object. Alright, now with this vehicle object, we can pick the label glass properties. So let's pick W2 class properties and assign it accordingly. Now once we are done, then we'll call the Save Changes is emitted. Alright, let's move towards the delete legal method. First, we'll make this async await keyword. And after this, we'll use DB context vector v equals property. And let's call the fine async method. Now, in satisfying async will pass this ID parameter. As always, this line will fetch the vehicle record from the database against this ID value stored in a variable and name it Michael. Then we're going to remove this vehicle. In order to do that, Let's call that DB context dot labels, device ID property, and call the built-in helper method that is removed. Inside this remove method, just pass this vehicle. Remember, in case if we move, we don't have an async method. So we just have to use the remove method here. And as I said earlier, when bulls use the insert, update and delete operation, then we also need to call the Save Changes method. Let's use the Save Changes async here. We have completed the service layer. Now, I'll see you in the next lesson. 17. Extension Methos and IOC in Vehicle Service: Earlier, we have created down Vico Service class, which is responsible for the basic crud functions. Now in this lesson we're going to work with the dependency injection inside the door open core project. Dependency injection, the design pattern that makes a class independent of its dependencies. In dependency injection, we don't rely on concrete implementation of a class. Rather we rely on the interfaces. This makes our code more maintainable. And almost in every enterprise project dependency injection pattern is used heavily. Let's say we have an interface and the service class. Now in future, we'll add a controller class. And they are, Let's say if we want to access the methods of vehicle service class, then we need to create an instance of a vehicle service class. Now, instead of making the object, will use the dependency injection IoC, Inversion of Control container, which will handle all the dependencies. Basically in the IOC container will disturb our interface and vehicle service class. And it's the IOC container which will resolve the dependencies for us. Now we don't need to create an object of legal service for accessing the methods of vehicle service class. We just need to pass the vehicle interface in the constructor. And with the help of this interface, we can access the matters easily. Now by default, ASP.net Core comes with the built-in IOC container. So we just need to use it. Let me tell you that in Dart and six version, microsoft has moved the Startup dot CS class. Earlier we register the IOC container in the startup class. Now in doctrine six, Microsoft.net team has just used a single program.cs class, which will handle all the stuff. From now we'll work with the program class. But if you're using some older version of Dalton core, then you'll see the static class here. Okay, We'll go to the program file. They will choose builder dot service. And right after that, we'll pick the ad Scope method in which we'll add i vehicle interface and the legal service class. Now, let's take responsibility of this L scoped, which will create a new instance of vehicle service class. If you're using the older version of Dortmund core, then you'll add this line in the configured service method of startup class. Okay, So we have registered the dependencies in the program dot CSS. Now, in the next lesson, we'll create the controller. So I'll catch you in the next lesson. 18. Vehicles Controller: In the last lesson, we have worked with the inversion of control container and we have resolved the dependencies in the IOC container. Now, in this lesson, we'll add a controller and inject the interface in the constructor of the controller. So let's go to the controllers folder and I'm going to add a new controller class. Make sure you have selected this API option. And then just pick this template with readwrite actions. This template will already contains some code and we just need to modify this. Then I'm going to name this controller to vehicles controller. Make sure that controller must ends with the keyword controller, because it's a naming convention. Let's add it. And here we go. You can see that this controller contains some built-in code for GET, post, PUT, and delete methods. We'll modify these methods according to your choice. First of all, let's create a field of type, vehicle interface, resolve the namespace, and give it a name which is underscore vehicle service. Now we're going to add a constructor by using this snippet CTE OR, and twice hit the Tab key. Okay, now let's inject the eye vehicle interface inside this constructor. Right after that, we'll assign this vehicle service to this underscore vehicle service. Now with this underscore vehicle service will pick all the methods that we have written in the I vehicle interface. Let's go to this getMethod. Currently it's returning the list of string. Let's remove this code. And instead of string, we'll use the eye innumerable of Laker. Just make sure to solve namespace for the modal class. Okay, now we'll add the async keyword along with this method. And right after that, we'll use this underscore vehicle service and pick this get all vehicles method, which will return the list of labels, will get an error. And it says the type of this method must be dusk. Use the task. Because this call is async. So we also need to use the await keyword here. Now we'll go to the other overload of getMethod. And this method is returning the string. Instead of using the string will make the type of this method to dusk off label. Use the async keyword. Then let's return underscore vehicle service dot get labeled by ID method, which will take the ID parameter as past this id here. And don't forget to use the let keyword. Okay, now let's go to the post method. And they will first make the type of this method to task and use the async here. Right after that we will use the await. Then use underscore vehicle service and pick the ad legal method. This ad vehicle method will take the object of vehicle class. Instead of using the string, let's add the vehicle class object and pass this vehicle here inside the add method. Similarly, we'll go to the put method. And this PUT method is just like the post method. There's only a slight difference between these two methods and that is the use of ID parameter. First will make the type of this method to task. Then use the async. And right after that we'll pass the vehicle here as a parameter. Now we'll use the await. Then choose underscore vehicle service, and pick the update vehicle method, which will take the id and the vehicle object. Okay, let's pass it. Now we'll shift to the delete method. And here, let's pick the type of this method to dusk and use the async keyword. Now, let's use the await here. And along with that, we'll use underscore Maker service dot delete method, which will take an ID parameter. Okay, so we have completed the functionality of the controller class. Now let's run this API and test that good functionality in the next lesson. 19. Run Vehicle Microservice: In the last lesson, we have worked with the controller class. Now in this lesson we will run our project and Tesla vehicles microservice. So let's quickly run this project inside of our browser. And here's you'll see the struggle documentation page for our API. At this moment, data equals table inside a database is empty. So first we will go to the post request and click this triad option. Then we need to add the JSon data here. Just remove the ID because ID is auto incremented, so we don't need to pass the ID here. Now, let's add some decent data and execute this request. Here we go. Let's add more data. Now let's go to the get request. Choose tried out, and execute this request. As soon as we will execute this request will get all the records. Let's say we just want to get the data of this vehicle, will simply copy the idea of this vehicle. Then we'll go to the other getMethod. And let's pass this id and execute the request. This time, instead of getting all the Legos data, we only get a single vehicle data. Okay, now let's say we want to update. This radical will go to the update method. And let's add the ID of the vehicle and gender JSon data. Now, let's execute the request to check whether this vehicle data has been updated or not, will again send a get request. And this time you'll see this vehicle data has been updated. Okay, now let's say we want to delete this vehicle. So we'll go to the delete request. We're going to pass the vehicle ID and just execute it. Now let's check whether this data has been deleted or not. So we'll send a get request. And here we go. We don't get any data. Alright, so far, we have worked with the vehicle microservice. Now, in the next section, we'll work with our customers, microservice. So I'll see you in the next section. 20. Overview Customer Microservice: In this section, we're going to create the micro service for customers. So let me tell you the basic flow of this customer's microservice. This Christmas micro service will be based on a single method which is at customer. Instead the client side. After mobile application or web application, the customer can add the details. And behind this, the post method or add customer method will be executed. You can also add other methods in discussion as micro service, just like we have added in the vehicle microservice, like get all customers, get customer by id, update customer and delete customer. But our requirement is just one method which is an add customer method. So let's start writing these customers micro service in the next lesson. 21. Create Models For Customers Service: In this lesson, we're going to start getting that customers microservice will open this customers micro service project. And then first of all, we'll add a modal class. And for this purpose, we'll get a new folder and name it models. Now inside this model's folder, we're going to add a new C-Sharp class. We name it customer. Okay, here we go. Inside this Christmas class. Let's add some properties like id of the customer, name of the customer, e-mail, and phone number of the customer. Okay, here we have added the necessary properties for customer mortal glass. Now let me tell you that what the customer wants to book a test drive for some particular vehicle. Then we also need to handle that vehicle service data. For example, let's say that the customer wants to book a test drive against this vehicle. So that means we also need to send them vehicle data to the customer, microservice. Normal rest APIs. We can achieve this via relations between tables. But here, the vehicle microservice has a separate database and the customer microservice will not create a database after vehicle microservice, but the customer microservice will replicate the data of the vehicle. Microservice is the general rule of microservice. That to microservices can not share that database, but they can share the data. So we'll apply this principle to our customers microservice. And here in Santa customers micro service will need to model classes. One for customer N14 vehicle. When the customer will book the test drive. Then we'll also send them vehicle name to the customer, microservice. In the vehicle class, we just need two properties. Now, equal id and then legal name. One customer can book a single vehicle at one time. So the vehicle ID will be the foreign key in the customer table. Okay, we'll add a property in the customer class, and let's name it Michael ID. Now let's add a property of glass Michael and name it Michael. This will create a one-to-one relation between the customer and the vehicle class. But where is the vehicle class? Let's get our vehicle class in this model's folder. And here we go. Now we'll add two properties, one for vehicle ID and the other is for legal name. Once we'll add the vehicle class, then you don't see any error in the customer class. Okay. Now, let me tell you that the ID in the vehicle class will be auto incremented. But we want to pass that ID, which will get when the customer wants to book some vehicle. Let's say this vehicle has the following ID. So when the customer wants to book a test drive of this vehicle, then we need to store the same vehicle ID in the vehicle table. On top of this id will add a key attribute and use that database generated option to none. That means ID in this table is primary key, but it's not auto-increment it. Okay, we have created two classes, one for customer N14 vehicle. Now, in the next lesson, we'll get the DB context class. So I'll see you in the next lesson. 22. DbContext For Customers Service: In the last lesson, we have created the modal class for customer and vehicle. And now in this lesson, we're going to create the DB context class. I've already told you that DB context act as a bridge between your model class and your database. So we'll save our time and create a folder, name it data. Then inside this data folder within the class. So instead of creating a new class, let's copy the API DB context class from the vehicle microservice. And then we're going to paste this class inside the data folder of customers microservice. Okay, now here we need to fix the namespaces because now we are inside a customer's microservice project. So we'll add the namespace for customers project. Then we need to DB set properties. One is for vehicle and the other is for customer. Db set property is already present. So we'll add a new property of type, customer, name it, customers. Now let's provide the connection string to this DB context class. We defined our connection string inside this own configuring method. This time we have working with the customers micro service projects. So we will not change anything here other than the database name. Okay, so I'll see you in the next lesson. 23. Migrations in Customer Service: In the last lesson, we have set up the connection string and we have also created that DB context class. Now, in order to create the database, we need to add them migrations. To enable the migrations, make sure you have installed this NuGet package inside your customer's Microsoft Project. Okay, now we'll go to the Package Manager console. And let's add the migrations. But before adding the migrations, the select the project in which we're going to add the migrations. This time we want to add the migrations in the customer's microservice. So make sure customer project is selected. Then in the Package Manager console will also select the customer project. Okay, Now let's add a command that is add dash migration and provides a user-friendly name to the migration. I limit initial create unless it enter. Okay, here we go. This will generate the migration script. The script will be used to add the database and tables. But we have not actually created the database yet. Again, in the Package Manager console, we'll use the command update dash database. And let's hit Enter. Now this will add the database and tables inside the SQL Server Object Explorer. Let me go to the SQL Server Object Explorer. There. Let's refresh the server. And if we expand this server, then we'll see the Databases folder. If we will expand this further, then we'll see our database for customers microservice. And if we will expand this again, then inside the tables will see the tables for vehicles and customers. Okay, So far, we've added a database and the tables. Now, let's continue our work in the next lesson. 24. Create Interface For Customers Service: In the last lesson, we have worked with the migrations. And now in this lesson, we're going to start with the interfaces. So what we're gonna do is we'll use the same strategy that we have used in the vehicle micro-service. First of all, let's add a new folder and name it interfaces. Then inside this folder, Let's add a new interface. We're going to name this interface to customer. Alright, let's add n Here we are. Now inside this interface, we're going to add a method of die das, name this method to add customer. This customer method is basically used to add the customer information. And inside this method, Let's pass the parameter of type customer. And for this customer, we need to add the namespace for models folder. Alright, so we just need one method for adding the customer and which we have added. If you want to add other methods like get customers, opted customer or delete customer, then you can apply the same strategy which we have used in the vehicle interface of legal microservice. But that's not a real project requirement. We will go ahead with this one method. Now, in the next lesson, we'll add the services from this interface method. So I'll see you in the next lesson. 25. Create Customers Service: Earlier we have worked with the interfaces, and now in this lesson, we're going to work with the services. So let's get a new folder and rename IT services. Then inside this folder, we're going to add a new C-Sharp class. Then we name it customer service. Alright, Inside this customer service, we write the implementation of method which we have defined in the eye customer interface. Let's implement this customer service class from II customer interface. Alright, there's all the namespace for this interface. Then we need to implement the method for this high customer interface. Now, we just need to add the logic inside this add customer method. But before this, let's add a field of type EPA DB context, result, the namespace. Then we'll name this field to DB context. Right after that, we'll add a constructor. And here we will get a new instance of API DB context and assign this to DB context. Now, with this DB context, we can pick the DB set customers and vehicles property, which we have defined in the APA DB context class. Let me tell you the logic which will write inside this method. Suppose a customer wants to book a test drive against this vehicle. So when he will provide the customer details than a record for customer a against this vehicle ID will be added. Now, customer B also wants to book a test drive against the same vehicle. So in that case, customer B record will be added. But as you know that Customer a and Customer B wants to book a test drive against the same vehicle and the vehicle ID is obviously same. That means we'll get the primary key error. Because the general principle of database table is that primary key is unique. So what we will check, the customer will book a test drive against some vehicle. Then we will first query from the vehicles table and check whether the vehicle is present inside the database or not. If no records exist. Then we'll first add a new vehicle inside the vehicles table. And right after that, if the vehicle is already there inside the database, then we'll set null to this vehicle property of customer class because the data is already there. And now there is no need to add the same legal record again. And right after that, we'll add the customer inside the database. Okay, let's add this code inside the add customer method. First of all, let's make this method Async. Then use the await keyword. And right after that, we'll pick the DB context dot vehicles DB set property called the first or default async method. And inside this, we'll use the lambda expression and check whether the ID of the legal stable is equal to that vehicle ID, which we will get from this customer object. Then let's store the result in a variable and name it legal in dB. Okay, now we'll check if the vehicle in dB is null. Then let's add the weight given to the DB context dot vehicles dot add async. And inside this, let's pass this customer. Then. As always, we'll use the DB context dot save changes async method. And don't forget to add the weight here. Okay? Now, if delta equal Racket is already present inside the database, then there is no need to add the same vehicle again in the database. Because this will cause a violation of primary key. Because the primary key is unique for every bucket. So in that case, we don't want to add the new vehicle record. And we'll set customer vehicle equals null. And right after that, we'll add the customers inside the database by using await keyword. Then we'll choose DB context dot customers, dot, add async, and pass this customer here. Right after that, we'll call a Save Changes async method. Okay, here we go. We have completed the service layer. Now, I'll see you in the next lesson. 26. Extension Method and IOC in Customer Service: Earlier we have created the customer service class. Now, in this lesson, we're going to work with a dependency injection inside the document Core project. As we discussed earlier, that by default, ASP.net Core comes with the built-in IOC container. So we just need to use it. Let me go to the program.cs file. And they will use the builder dot service. Right after that, we'll pick the ad Scope method in which we will add the customer interface and the customer service class. Now, it's the responsibility of this ad scope, which we'll get a new instance of customer service class. Okay, So we have registered the dependencies in the program.cs class. Now, in the next lesson, we'll create the controller. So I'll get you in the next lesson. 27. Customers Controller: In the last lesson, we have worked with the inversion of control container and we have resulted dependencies in the IOC container. Now, in this lesson, we'll add a controller and inject the interface in the constructor of the controller. So let's go to the controllers folder. I'm going to add a new controller class. Make sure that you have selected this API option. And then just pick this template with readwrite actions. This template will already contains some code and we just need to modify this. Then I'm going to name this controller to customers controller. And let's add it. You can see that this controller contains some built-in code for GET, post, PUT, and delete methods. In the customer's controller. We don't need all these action methods. We just need a post method. So first of all, let's remove the rest of the code inside the customers controller. Okay, here we go. Now let's get a field of type II customer interface. Here's all the namespace. And give it a name which is underscore customer service. Then we're going to add a constructor and inject the customer interface inside this constructor. Right after that, we'll assign this customer surveys to this underscore customer service. Okay, now we'll go to this post method. Let's make the type of this method to task and use the async here. Right after that, we would use the await keyword. Then we use underscore customer service and pick the add customer method. This add customer method will take the object of customer class. So instead of using the string here, let's add the customer class object and then pass this customer here inside the add customer method. Okay, so we have completed the functionality of the customer class. Now let's run this API and test add Casper functionality. In the next lesson. 28. Run Customers Service: In the last lesson, we have worked with a controller class. And now in this lesson, we'll run our projects and tests the customers micro service. If you want to run both customers and vehicles microservice, then right-click on the Solution. Then click Set as data projects. Currently, single starter project is selected. So we will choose multiple starter projects and then pick the Start option for this customer and legal project and hit Okay, right after that, let's run the projects. And this time, we'll Studio will build two projects, one for customers and the second is for vehicles. Okay, let's go to the vehicles project and execute a get request. And here we'll get the list of labels. Let's say the customer wants to book a test drive against this vehicle. Obviously, the customer will have a good-looking user interface. For this purpose. You may have a mobile application or web application for booking the desk drive. But right now, we didn't have micro-service development. So we need to pass the vehicle ID manually. In case of web application or mobile application, this will be done behind the user interface. And the user who is using the mobile application will have no idea what's going on in the back-end. You'll just see the user interface. So we'll suppose that the customer wants to book a test drive for this particular vehicle. So we'll switch to the customers microservice. And there, Let's go to this post request. And right after that, let's add a customer's data. Then we need to pass the vehicle ID and legal name here. Then let's see the post request and here we go. Now check whether this record is added or not. So we'll switch to the SQL Server Object Explorer and let's refresh it. Open the database for customers microservice. And here, if I will, open the customer table and you'll see that the record has been added. Similarly, we'll open the vehicles table and the record is present here. Now let's see. Another user wants to look at desktop for the same vehicle. In the customer's microservice will add the details of another user. And because he also wants to book a desktop for this vehicle, so we will not change that label id. Okay, let's send a request. And here we go. Now in the customers table, if we refresh it, then we have two customers. And if we refresh the vehicle table, then here we just have one vehicle because to customers wants to book a test drive for the same vehicle. And that's why we only have one vesicle inside the database. Okay, so I hope you got an idea of what's actually happening in the customer's microservice. That's all from this lesson. Now, I'll see you in the next section. 29. Azure Service Bus Overview: In this section, we're going to work with the Azure Service Bus. Let me tell you what is Azure Service Bus? Azure Service Bus is basically a cloud messaging service and it's fully managed enterprise message broker with message queues and publish subscribe topics. Basically, it's used to connect any applications, devices, and services running in the Cloud to any other applications or services. With the help of Azure messaging service, we can exchange data between two or more than two services. Earlier we have created the customers microservice, and I want to tell you that men will add the customer's data. Then we will also send a copy of data to the Azure messaging service. And then we'll get the reservations microservice. Then we'll get that data from the Azure Bus. Tick off azure burst as a queue where a center, which in our case is the customer's microservice, will send a message to the Azure messaging queue. And later the receiver, which will be the reservation service, will get that message from the Azure Queue. So in this section, we'll work with the center part of the Azure messaging bus. And later when we'll use that as a vision microservice, then we'll work or the receiver part of the Azure Service Bus. Okay, so let's start working on the Azure Bus from the next lesson. 30. Setting Up Azure Service Bus: In this lesson, we need to create the Azure Service Bus queues. So let's go to the Azure portal and we're going to select this, Create a Resource option. Okay, then in the search bar, Research Service Bus. And just select this. You'll see the details of service bus like a sack cloud based messaging service, providing cues and topics. In this course, we'll work with the queues. Let's create the Service Bus. First of all, we need to choose the resource group. Think of this resource group as a folder in which we can add multiple things. Let's create a new resource group at Gibson user-friendly name. Alright, then let's add the namespace. Well, a namespace is actually the URL of your Service Bus. Make sure this is unique. Then we need to choose the location where we want to get the Service Bus. Just select any location, RG or nearby location. Then we have an option of pricing with some plants like basic, standard and premium. In this course, we will use the basic plan. If you'll click this View Full pricing details, then you'll see all the plans with their prices and functionalities. The basic plan is quite cheaper. So we will choose this because we're not working with the topics. So this basic plan is perfect for this course. Let's click Review plus Create option. And this will perform some validation check. Once the validation is succeeded, then we'll select this option. Deployment starts. The deployment is in progress. So we need to wait here. We will see a message, we see the deployment is complete. Now let's go to the Resource option. We need to create the queue. Here. We'll select this kid Q option. And then we have been asked to name our cube. Let's provide some user-friendly name to our queue. Then we'll go to the default settings. Here I need to tell you that this message time is 14 days. It means if the message will not retrieve from the queue, then after 14 days the message will be removed from the queue. You can increase or decrease the time. But I'll go with the default settings. Let's get the Q. And R Q is currently being created. Soon we'll see a message which says your Q was successfully created. Now, in the next lesson, we'll send that data to this cube. I'll see you in the next lesson. 31. Azure Sender Service: In the last lesson, we have created the Azure Service Bus queue. And now in this lesson, we're going to send that data from the Christmas micro-service to the Azure Service Bus queue. So first of all, let's go to the studio. And they will right-click on the customer's microservice project. Select Manage NuGet packages. And right after that, lets us this NuGet package for Azure Service Bus. The name of this package is Azure dot messaging, dot service plus. Alright, we're going to install this NuGet package. And here we go. Once the installation is done, then we'll go to the Project link of this package. And here you will see Getting Started guide for using this package. Just scroll down. And here we have a sample code which tells us how to send a message to the Azure Service Bus. First, we'll deduct connection string for our Azure Service Bus. Then you'll need a queue name where we want to send a message. Right after that, we'll create a service bus line, which takes a reference to the connection string. Then we'll get a center, which we'll get a reference to the queue. Then we'll get a Service Bus message with take a message that we want to send. And finally, the sent message ac method will send a message to the Azure Service Bus. Similarly, when we want to receive the message, then we'll use this code. But right now our focus is to send a message to the Azure Service Bus. So we'll focus on this code later when who worked on the reservations microservice. Then we'll also talk about this received message code for Azure Service Bus. Okay, so we'll go to the video studio. And I'm going to add the code for sending data to Azure Service Bus. Let me go to the Customer Service. And inside this add customer method, we can to write the code for sending data to Azure Service Bus. So we'll go to the GitHub Documentation page of Azure Service Bus. And they will see this code, just copied that part of this code. And then in the customer service class, we'll paste this code. Now, we need to modify this code a little bit. First of all, we need to resolve the namespaces. Then we need to pass the connection string and the queue name. In order to get the connection string will switch to the Azure portal. And then we'll go to the Azure Service Bus. Will open the Service Bus. And right after that, we will see the Shared access policies. Just click this and then we'll see this road manager shared access key will select this. Then we'll see a primary connection string. We're going to copy this connection string. And right after that, we'll switch it up. We'll studio space disconnects this thing here. Okay, Now what about the queue name? Again, we'll switch to the Azure portal. And on the right-hand side, we'll see these cues. Just select this. And here we'll see our queue name. Will pass this queue name inside a customer service class. Alright, here we go. Now let me tell you that this code is perfect to send the data to the Azure Service Bus. But the problem here is this code will just send a string message to the Azure Service Bus. But we want to send the customer object. So what we're gonna do is we'll first satellites the customer object to JSON. And then we'll send the customer object. So we'll use decent convert dot civilized object and 40s Jason convert to use the neutral soft NuGet package. And the namespace. Then industrialized object will pass this customer object. And this object will convert this Christmas object to JSON string. Let's total result in a variable. And we then made object as text. Then the Service Bus message will pass this object as text. Alright, now let's run the project. And let's say the customer wants to book the vehicle desk drive against this vehicle ID. So we'll pass the necessary details here. And then let's send the post request. Okay, here we go. Now, if we go to the SQL database, then we'll see that that customer record has been added. Then we'll go to the Azure portal. In the Azure Service. Let's go to the cues, select our queue. And right after that, we will see this service bus Explorer preview option, deselect this. We'll adapt this big option. Here we'll see the details in the JSON format which we send from the CRISPR micro service. Alright, so we have edited data to the Azure Bus queue. Now, when we work with the reservations microservice then will consume this data from the Azure Bus queue. So that's all from this lesson. Now, I'll see you in the next section. 32. Reservations Service Overview: In this section, we're going to get the microservice far as iterations. Let me teach you the basic flow of this reservations microservice. This reservation microservice will be based on two methods. And these are get reservations and update status. When the customer will book a test drive of some vehicle, then one copy of that data will go to the Azure Service Bus queue. And now in the reservation service will call the get reservations method. And inside that get reservations method, first, we'll fetch the data from the Azure Service Bus queue. Then we'll store the data inside the database. And right after that will display the list of reservations. And the other method is update male status, which will be used to send a confirmation email to the customers, will explore things as we move forward in this course. Okay, so let's start writing that admissions micro service in the next lesson. 33. Create Models For Reservations Service: In this lesson, we're going to start getting the reservation microservice will open this reservation micro service project. They are, first of all, we'll add a modal class. And for this purpose, we'll create a new folder and name it models. Inside this folder, we need a class which will hold the data which we want to fight from the Azure Service Bus queue. Inside the Azure Service Bus queue, you will see that we have following JSon data. Let's copy this JSon data. And then we'll go to the gym to C-sharp website. And they're just paste this DSM engineered a CTL properties. Okay, here we go. We have two classes than glass. At the root class. Let's create these glasses inside the reservations microservice project. Inside that we'll studio. We're going to create a new C-Sharp class. And then we named this class to legal. Right after that, we'll copy the properties of this vehicle class and paste it inside this glass. Now we'll get another class. Well, Jason to CTL website has named this class to route, but we want to give some other name to this class. Let's say we want to name this class to Reservation Data class, intimate reservations. Okay, now we'll copy these properties and paste it inside the reservation glass. Now, inside the reservation class, Let's add one more property which tells us whether the confirmation email has been sent to the customer or not. So we'll add a property of dipole and name it is male scent. Then in that particular class, we can't make this ID as a primary key because we'll get this id from the Azure Service Bus queue. And what if two customers booked the same vehicle? Which means the data that will get will be in the following format. Where two different customers, the vehicle test drive for us same vehicle and the vehicle ID is obviously same. And if you try to store the same vehicle ID twice, then we'll get an error of primary key, because primary key must be unique. So we'll add another property in the vehicle class and name it V. Let's make this property as a primary key by adding the key attribute and then dissolve the namespace. Okay, here we go. We have created the model classes. Now let's continue our work in the next lesson. 34. DbContext For Reservations Service: In the last lesson, we have created the model class for reservation and vehicle. And now in this lesson, we're going to create the DB context class. I've already told you that DB context act as a bridge between your model class and your database. So we will see a time and create a folder, name it data. Then inside this data folder within the class. So instead of creating a new class, we're going to copy the APA DB context class from the Waco microservice and then paste it inside the data folder of reservation micro service project. Now, we need to fix the namespaces here, because now we're inside the reservation microservice projects. So we will add the namespace for reservations project. Then we need to DB set properties. One is for radical and the other is for reservation. So we're going to add a new property of type reservation and name it reservations. Okay, now let's provide the connection string to this DB context class. We defined our connection string inside this on configuring method. This time we're working with our reservation microservice project. So we'll name our database to reservation API db. Ok, now in the next lesson, we'll add the migrations to add the database inside the SQL Server. So I'll see you in the next lesson. 35. Migrations In Reservation Service: In the last lesson, we have set up the connection string and we have also created that DB context class. Now, in order to create a database, we need to add them migrations. To enable the migrations, make sure you have installed the NuGet package inside your reservations microservice project. Then we'll go to the Package Manager console. And we're going to add the migrations. But before adding the migrations, just select the project in which we're going to add them migrations. This time we want to add the migrations in doubt reservation microservice project. So make sure as innovation project is selected. Then in the Package Manager console will also select the reservation microservice project. Now let's add a command that is at the migration. Then provide a user-friendly name to the migration. I'm going to name it initial, create, ls, hit Enter. This will generate the migration script. This script will be used to add the database and tables, but we have not actually created the database yet. So again, we'll switch to the Package Manager console. Here. I'm going to add a command that is update dash database unless it Enter. And this will generate the database and tables inside the SQL Server Object Explorer. So let's go to the SQL Server Object Explorer and then less effect the server. Okay, If we expand this server, then we will see the Databases folder. If we will expand the databases, then we'll see our database for reservations microservice. And if we will expand this again, then inside the tables will see the tables for vehicles and reservations. Okay, so far we have added the database and the tables. Now let's continue our work in the next lesson. 36. Create Interface For Reservations Service: Earlier we have worked with the migrations, and now in this lesson, we're going to start our work with our interfaces. So what we can do is we'll use the same strategy that we have used in the legal micro-service. Let's add a folder and name it interfaces. Then inside that folder, we're going to add a new interface. And this time we're going to name this interface to reservation. Okay, let's add it. And here we go. Now inside this interface, let's add a method of die, das list of reservation. Then there's all the namespace name. This method to get reservations. This get reservations method is basically used to get the list of reservations which will get from the Azure Service Bus queue. Once we will get the reservations, then we will send a confirmation email to those customers who book the vehicle for test drive. So we will add another method of type task. And then we'll name this method to update male status. And this method will take the reservation ID, will pass ID here of integer type. Okay, so we have added these two methods. One for getting televisions list and the other is used to send a confirmation email to the customers. Now, in the next lesson, we'll add the services from the interface methods. Okay, so I'll see you in the next lesson. 37. Create Reservations Service: We have worked with the interfaces, and now in this lesson, we're going to work with the services. So we're going to create a new folder and name it services. Then inside the folder, we're going to add a new C-Sharp class. At this time we name it has elevation service. Okay, now, inside the class who write the implementation of methods which we have defined in the reservation interface. So let's implement this exhibition class from reservation interface. Then result in namespace for this interface. And right after that, we need to implement the methods for this either as a visual interface. Okay, so we just need to add the logic inside this, get reservations and update male status methods. But before this, let's get a field of type API DB context, all the namespace. Then we'll name this field to DB context. Then we're going to add a constructor. And here we'll create a new instance of API DB context and assign this to this DB context. Now with this DB context, we can pick the DB set reservations, and vehicles property, which we have defined in the APA DB context class. Let me tell you the logic which will write inside the get reservations method. As you know that we have Azure Service Bus queue where we have sent a data in the customer's microservice and now in the reservation microservice will fix that data from the Azure Service Bus queue. Then we'll save that data inside the MS SQL server database. And right after that will return the data. So we'll fetch the data from the Azure Service Bus queue later in this course. So I'll add a comment here that we will add the Azure Service Bus receiver code later. Then we'll return this DB ctx dot reservations, da2 list async. Don't forget to add the async await and make sure to resolve the namespaces. We have left this step where it will fetch the data from the Azure Service Bus queue. But don't worry, we'll move forward, then we'll complete dysfunctionality. Let's move to the second method, which is update status. This update meal status will add a logic to send a confirmation e-mail to the customer. Let's say we have the following data in their reservations table for few customers. Now we want to send a confirmation email to this customer. So we will use this update male status method. We will pass the reservation ID. Then we'll check whether the record is present in the reservations table for this reservation ID or not. If the record is not null and this is male scent property is false, then we'll send an e-mail to the customer. And right after that, we'll set that is mail sent property to true and just save the changes. So let's add this code inside this update status method. First we'll add this DB context dot reservations dot find async method and pass this id. Then we use async await. Right after that we will store the result in a variable and just name it as a result. Now we will check if the reservation result is not null. And this is male-centered property is false, then we'll add the logic to send that e-mail to the customer. So for sending emails, let's initialize the SMTP client. Then dissolve the namespace. In this SMTP client. First we'll set the port number 2587. Then we'll add a property credentials and initialize a new instance of network credentials. Then inside this will pass the email and password. For this tutorial. I'll recommend you to make some extra e-mail for testing purpose. Then we'll use the enable SSL and set to true. Once we add that part of the code, then we'll use this SMTP client and call the send method. And descent method will take four things from two, subject and polish. The first parameter, which is from, we'll pass our email address. And in the second parameter, which is to the recipient, we need to pass the e-mail. That customer really want to send that email. And we'll get this from the database by using the reservation itself, Dodd email property. Then in the subject, Let's pass a message. And also in the body, just add some text. Alright, this code will send a confirmation e-mail to the customer. Now, once we will send the e-mail to the customer, then we need to set this is male scent property to true. And right after that, Let's call the Save Changes async method. Okay, That's all from this lesson. Now, I'll see you in the next one. 38. Extension Method and IOC in Reservation Service: Earlier, we have created the reservation service class. Now, in this lesson, we're going to work with the dependency injection inside the doctrine core project. As we discussed earlier, that bite fork.net core comes with a built-in IOC container. So in this lesson, we're going to use it. Let me go to the program.cs class. And here we'll use the builder dot service. And right after that, we'll pick the ad Scope method in which we'll add the ideas innovation interface and the reservation service class. Now, it's this possibility of this add scoped, which we'll get a new instance of the reservation service class. Okay, So we have registered the dependencies in the program.cs class. And now in the next lesson, we'll create the controller. Okay, I'll catch you in the next lesson. 39. Reservations Controller: In the last lesson, we have worked with the inversion of control container and we have to solve the dependencies in the IOC container. Now, in this lesson, we'll add a controller and inject the interface in the constructor of the controller. So let's go to the controllers folder and I'm going to add a new controller class. Make sure you have selected this API option. And then just pick this template with readwrite actions. Now let's name this controller to reservations controller. You can see that this controller contains some built-in code for GET, post, PUT, and delete methods. In the reservations controller. We don't need all these action methods. We just need two methods. One for getting data that vision list. And the second is used to send the e-mail to the customer. For sending the e-mail to the Customer, we can use the put method. So we'll remove other methods except the port and the getMethod. Now, let's create a field of type either salvation interface is all the namespace and give it a name which is underscore reservation service. Then we'll add a constructor and inject the reservation interface inside the constructor. Right after that, we will assign this reservation service to this underscore reservation service. Okay, now we'll go to this getMethod. First of all, let's change the return type of this method to dusk I innumerable of preservation. Then use the async here. And right after that, we will use the await operator. Then we'll use underscores envision service and pick the get reservations method. Okay, right after that, we will store the result in a variable and name it reservations. And finally, return the reservations. Then we'll go to the put method. Here. We don't want to pass the object because this update middle status will just take an ID parameter. So we'll remove the other parameter from this method. Then we'll turn the type of this method to task. And right after that, we'll choose underscore reservation service. Then pick the update middle status method and pass this id here. Don't forget to add await async. Alright, so we have completed the functionality of the controller class. Now in the next section, we'll fix that data from the Azure Service Bus queue, and then we'll complete the admissions method of reservation service class. Okay, I'll see you in the next section. 40. Azure Service Bus Receiver Overview: In this section, we're going to work with the Azure Service Bus. Later in this course, we have sent the data to the Azure Service Bus queue when we've worked with our customers microservice. Now in this section, we'll fetch that data from the Azure Service Bus queue will target this reservation project. And inside this, I'm going to install the NuGet package. As always, we'll right-click on the reservation project, then go to the Manage NuGet packages. And here I'm going to search this new vote for Azure messaging service bus. Alright, let's install this package. And here we go. It's solution has been completed. And now in the next lesson, we will write the code to fetch the data from the Azure Service Bus queue. So I'll see you in the next lesson. 41. Azure Consumer Service: In this lesson, we need to fetch the data from the Azure Service Bus queue. In the last lesson, we have installed this NuGet package for Azure messaging service bus. Now, if you'll go to this project link of the package, then we will see the sample code of how to use this package. Scroll down. And this is the code I was talking about. We have used this code earlier in the customer's micro-service to send the data to the Azure Service Bus. And now we'll use this code to fetch the data from the Azure Service Bus. There's only a slight difference between the sender and the receiver code. Earlier we have used this code to send the data to the Azure Service Bus queue. Now let me tell you that we will still use these lines of code for connection string, queue name, and Service Bus client. But rather than using the sender code, this time we'll use the receiver code. We'll go to the customer service project. In the service class. We have used these lines of code for connection string, queue name, and Service Bus client has copied these lines of code. And then we'll go to the red emission service. And in the get reservations method, I'm going to paste this code. Okay, now let's resolve the namespaces. Then we'll go to the documentation page of this nugget. And let's copy these lines of code and paste it inside the reservations method. Now, let me tell you that currently this code is used to get a single string message from the Azure Service Bus. But we want to get the list of records and the records are in the JSON format. So this service bus received message will be of type. I, need only list. Let's give some name like received messages. Okay, right after that, Let's say we want to fetch ten records in a single request. So we will pass Then here. Then we check if the received messages are null. Then return null here. Otherwise, bulls use the for each loop for arbitration. So let's add a for-each loop. And here we want to hydrate in this received messages. So we will use Service Bus received message and name it received message. Then we'll add in keyword and use the received messages, which is our list. Okay, we'll cut these lines of code and paste it inside this foreach loop. Basically this line is used to get the body of the data and convert it into string. Okay, now the data that will get will be in the form of JSON, and we need to convert the JSON data into C-Sharp objects. So we'll use just one convert. Dissolve the namespace. This decent convert comes from the neutrals of package. Then we'll call this satellites object. We want to map this body according to the reservation class. We will pass reservation here and body here. Then let's store the result in a variable and name it message created. Once will fetch the data, then store it inside the database. So we'll use DB context, dot reservations, add async and pass this message created. Then use the await keyword. And right after that, Let's call the Save Changes async method. Okay, This code is enough to fetch the data from the Azure Service Bus and store the data in the reservations table. Now, let's say we have five lectures inside the Azure Service Bus queue. And was will fetch those five records and store the result in reservations table. Then we need to remove those five records from the Azure Service Bus queue. And on the documentation page, you can see that we have this complete message code. And it says that in order to remove the message from the queue or subscription, we need to call the complete async method. We will use this line of code. What I'm gonna do is I'll copy this line and then paste it inside the for each loop. Alright, we have added all the code for fetching the data from Azure Service Bus queue. Now, in the next lesson, we'll run the reservations microservice project and check the functionality. So I'll see you in the next lesson. 42. Run Reservations Service: In the last lesson, we have created the code for getting data from Azure Service Bus queue. Now, in this lesson we're going to run the reservations micro-service to check the functionality. So before ending, that is invasions micro-service. First, Ireland, the customers microservice and try to add some data inside the Azure Service Bus queue. Okay, here we go. We have added few records. Now let's try to run that as admissions microservice. And here we go. Our reservations micro service is running. Now let's try to call the get reservations endpoint. And behind the scenes, it will fetch the data from the Azure Service Bus queue, and we'll add it inside the reservations and the light goes stable. And finally, we'll get the result here. Okay, here we go. We'll get the data. Now, if you'll go to the reservations table and vehicles table, then we will see the records which we got from the Azure Service Bus queue. Now let's say we want to send a confirmation email to this customer. So we'll pass the ID of this customer in the update status method and send that request. Okay, here we go. Now, if the event is correct that it will send a confirmation e-mail to the Customer here. I have checked it and you'll see that we've got a confirmation email. Okay, That's all from this lesson. Now, I'll see you in the next section. 43. Api Gateway Overview: In this section, we'll talk about an API gateway. So what exactly the APA gateways and why we need API Gateway microservices. Let me tell you that an API Gateway is an API management tool that sits between a client and a collection of back-end services. This definition is 100% correct. But let me make things easier. Suppose you have few micro services like vehicles, customers and reservations. And a client, which could be a mobile device or application, can talk to our microservice with the different URLs. Instead of giving an access to all these URLs, we'll add a gateway right after the client or in front of the microservices. Now, in the API gateway will configure all the code to access these micro-services. But the client will not know the URL of microservice. If the client wants to test the vehicle microservice, then the client will send a request to the API Gateway. And API Gateway will send a request to the vehicle microservice and get the response. And right after that, API Gateway will return that responds to the client. In short, API Gateway is used to protect your APIs from our use and abuse. Because in API Gateway, we can also use rate-limiting. Whenever microservices are very complex and when we want to scale, then API Gateway will play a very important role. Load balancing is also very perfect with API Gateway. In short, we can see that there are multiple benefits of using API Gateway. And in the next lesson, we'll configure the NuGet package for using API Gateway. I'll see you in the next lesson. 44. Setup Api Gateway: In this course, we'll use the ocelot API gateway. So before moving forward, let's go and get a new doctrine called API project. Will name this project to API Gateway. Alright, let's add this project. Now, let's do a few things inside this project. We don't need the controller and the model classes. So we'll remove the controllers folder. And then we will also delete the weather forecast class. Okay, now the project is empty and it just contains the app settings class and the program class, which we need to configure the API Gateway. Now inside this project to add the NuGet package for ocelot. We'll search for this API gateway package, which is ocelot. Then let's install this package. Okay, here we go. The package has been installed. Now we'll go to the program glass and they will configure this ocelot package. First we'll add builder dot services. Then we will use to add ocelot method here. For this ADD ocelot method, we need to resolve the namespace, that is ocelot dot dependency injection. Again, we'll use f dot. Then we will add use ocelot method here, which will configure the middleware. And for this purpose, we'll add this namespace that is ocelot dot middleware. Alright, so these two lines are important to configure the ocelot. Now, in the next lesson, we'll map the routes for API gateway. So I'll see you in the next lesson. 45. Configure Routes: In the last lesson, we've installed a NuGet package for ocelot. And now in this lesson, we're going to add the route for API gateway will go to the app settings dot json file. And we'll start over. I'm going to tell you a few things. Let's take a look at this picture. We have a client and API Gateway and a legal service. The client will know the URL of API gateway. So the client will send a request to that API Gateway. And API Gateway will further send the request to the microservice. This URL which is exposed to the client, is an upstream URL. And the URL of the microservice is the downstream URL. Okay, just remember this, upstream and downstream because we'll use it heavily inside the API Gateway. Alright, let's go back to the app settings dot json file. And we'll add the routes. So let's use the routes. Then open the square brackets. And inside this will add the curly brackets. Now let's use the downstream but doublet. The downstream part template is basically the endpoint of the microservice. I know you're thinking that how to find the APA end point. Let's say we want to find the API endpoint for local micro service project. So we'll run this vehicle microservice. Here, instead of a browser, we'll see the end points for these methods. This slash api slash vehicles is the endpoint of this method. And similarly, we have endpoints of all the methods. Okay, let's start with this get method, which will return the list of vehicles. As we know that the end point for this request is slash api slash vehicles in the downstream path template whose use slash api slash vehicles. Then we'll add the downstream scheme. And here we need to set the HTTPS because we want to access the HTTPS protocol right after that. Use the downstream hosts and ports. And then let's add the square brackets. And inside this will add the host and port number. The host is local host because we are running down legal microservice inside the local host. So this will be the host and port number. We need to pass the port where vehicle microservice is running. Let's check in which poor we're running the vehicle microservice. So if we will run the vehicle microservice project that we'll see the port number. Let's copy this port number. Right after that. We'll go to the API Gateway app settings file. There. Let's base this port number. Alright, then place a comma separator after the square bracket. And outside this will add upstream bot template. As we discussed earlier, the upstream part template will be that URL, which is exposed to the client, will expose this slash gateway slash vehicles to the client. Alright, then we'll add the upstream HTTP method. And here we need to define this upstream part of that will target how many HTTP methods? Let's add the Gettier. If will go to the web browser. Then we'll see that both GET and post head same endpoints. So we will also add boost in the upstream HTTP method. Alright, that's it. Just like that. We need to add the route for other methods. So we'll add a comma. Then instead of adding the code, I'll just copy this part and paste it here. Let's say this time we worked out good, Get, update and delete methods. And these methods have the same API endpoint. In the downstream path template will add slash, api slash, vehicles slash. And then we'll add the ID in the curly brackets. Now, in the upstream part template will also change the URL to slash gateway slash vehicles. Right after that, we'll add slash id in the curly brackets. Then in the abstract method, we want to tell how many action matters this route will target. With this route will target, GET, PUT, and delete. And we'll add these HTTP methods here. Alright. Now just like this, we need to add the routes for other micro-services like customers and reservations. So again, let's copy this code and paste it here. This time, we're going to target the customers microservice. So what I'm gonna do is I'll just run the customer's Microsoft Project. Will see the routes. We just have one route which is slash api slash customers. So we'll add it here at the port number. So we'll copy the port number of customers micro service project. And then paste it here. Right after that, less than the upstream bot template to slash gateway slash customers. And obviously this case plus microservice will talk with the post method. So we'll add post STP action method here. Then we'll copy this code and paste it here. This time we're going to target the reservations Microservice. Again, what I'm gonna do is run that envisions microservice project. And here we'll see the APA end points. We have two different routes here. So first, we'll use the code for this slash api slash reservations. In the app settings file will change as template to slash api slash reservations. Then we'll add the port number here forever. Reservations microservice project. Right after that will change the downstream part template accordingly. Then this outlet darker getMethod. So make sure to add the action method here. Okay, Let's copy this code for as a vicious route and paste it once again. This time we'll change the API endpoint according to this PUT method. So we will use slash, api slash reservations, and then we'll add the ID in the curly brackets. Similarly, we'll add the ID and the downstream part template. Then in the upstream HTTP method will pass. But because we want to die Good put action method from this allowed URL. Okay, here we go. We have completed the code for API Gateway. Now, in the next lesson, we'll check the functionality. So I'll see you in the next lesson. 46. Test Api Gateway: In the last lesson, we have added a quote for API Gateway. And now in this lesson, we're going to desktop micro services via API Gateway. Alright, now I'm to run all the four projects. So we'll right-click on the Solution, then set starter projects and just make sure this multiple starter projects is selected. Then we'll start all the projects and hit Okay, let's run the projects. And here we go. This will load all the four projects. Now we're using the API gateway. That means we will not use the vehicle, customer or reservations project directly. We'll choose an API Gateway. Api Gateway project. Let's add API endpoint for vehicle. And hit Enter. Here we go. We'll get w equals theta. Similarly, you can check other end points. I want to tell you that this API gateway doesn't contain the documentation for APIs. So in order to check the other end points like post, PUT and delete unit is use the Postman tool. You've already covered how to test our APIs via Postman inside my last APA course. Okay, That's all from this lesson. Now, I'll see you in the next one.