Hello, Friends, Welcome to the next lab. In this lab, we will learn what is VPN? Actually, API means application programming interface is a dotnet Web API. It is a framework for creating a web API. And this, it sits on top of the dotnet core framework, because in this, we will create a pm on dotnet core framework 2.2 version. When you create a VPN, it will be consumed by server and client, like your website, mobile apps.

Next up IoT devices. Actually, what is the meat of it? In today's world, the data is stored on a cloud. And you can use several devices on which you can access that data from Cloud. So, there may be a communication medium for your application and the database. This communication it work on VBA.

Now, we will learn what is the RESTful API, RESTful API and restful services. The same list, it is an architectural pattern for creating API. And in this, it use HTTP protocol for communication. There are six constant of rate. In this first one is a plan server means Plan sent and request and server respond to that request. Separation of concern is achieved here.

Next is a stateless what means stateless communication between the client and server must be stateless means we are not saving any client data on server. So for processing the request on server, client needs to send the respect to data along with that request. So server will process that request. And therefore, every request is treated as independent by the server. Next one is a cacheable. Now, there may be a condition where the 1020 1500 client use the same server They might want the same data okay.

So, for that, when the client requesting that resources on a server, we can cache that data. So, using caching, we can achieve the performance and the processing get fast. Next one is a uniform interface, uniform interface or this unit to understand some concept of some term. First one is an HTTP verb. There are several HTTP verbs. In this.

We mainly use, get, put, post and delete. After that your means or resource name. Whatever you call for image, audio fine Data JSON data XML file like that, all our resources, and it will be identified by the specific URL. So, the interface, uniform interface constraint defines the interface between the client and server. It simplifies and decouples the architecture. Okay.

Next one is a layered system. In a layered system. We can take an example like our API, sit on a server a, our data will sit on a server B, and our authentication logic for our API sit on server C. So client cannot ordinarily tell whether it is connected directly to the end server, or a data server like that. This is a layer system means each part, we can do it into the model and place that respect to part on the super server layer kind of architecture. After that last one is a core on demand. Because an optional constant cookie, you'll know that you might have the APC data in the form of JSON or XML.

But there might be the condition where client needs some code that is that will be executed on the client machine. So for my product purpose when client decreased such kind of resources on APA it will save that code and it will run by the client by using applets My screen. So that's all about rest, rest constraint. Thank you for watching.