1 00:00:04,790 --> 00:00:12,880 Welcome to another important concept and that is express media where. 2 00:00:13,790 --> 00:00:23,870 To better understand express you need to understand Major World because Express is all about Meadow 3 00:00:23,870 --> 00:00:24,530 World. 4 00:00:24,740 --> 00:00:29,180 So let's see what Express Meadow World is all about. 5 00:00:29,390 --> 00:00:38,330 Where Express Meadow works are functions that have access to the request object and then the response 6 00:00:38,330 --> 00:00:39,080 object. 7 00:00:39,950 --> 00:00:45,680 If a function can have access to the request object and then the response object. 8 00:00:45,710 --> 00:00:54,800 It tells you how important it is and with the same word it can be used to modify the request object 9 00:00:54,800 --> 00:01:01,790 before they are passed to the next meadow world or before it can get into our route. 10 00:01:02,210 --> 00:01:06,800 So let's see importance of many words and some of the use cases here. 11 00:01:07,370 --> 00:01:13,700 Well, one of the use cases of many words is to implement what is called authorization. 12 00:01:14,240 --> 00:01:18,440 There is differences between authorization and authentication. 13 00:01:18,920 --> 00:01:26,210 Authentication simply means that allowing a user to log in into your system with the right credentials, 14 00:01:26,300 --> 00:01:35,150 email and password if the details are valid and after logging in, what do you want the user to take 15 00:01:35,150 --> 00:01:36,500 inside your application? 16 00:01:36,770 --> 00:01:39,260 And that is what you call authorization. 17 00:01:39,260 --> 00:01:43,280 And we can use middleware to implement authorization. 18 00:01:43,460 --> 00:01:50,780 And after that we can also implement middleware to do what is called login, meaning we can display 19 00:01:50,780 --> 00:01:57,380 custom messages upon each request and we can also use middleware for error handling. 20 00:01:57,380 --> 00:02:00,020 And you talk about all these ones. 21 00:02:00,290 --> 00:02:06,170 After that, we can use middleware to implement what is called rate limiting. 22 00:02:06,530 --> 00:02:14,630 This simply means that let's say we have an endpoint or route for fetching or posts, we can implement 23 00:02:14,630 --> 00:02:20,660 it in such a way that a user can make a request five times that endpoint. 24 00:02:20,660 --> 00:02:23,750 If you make a request, that list is six times. 25 00:02:23,750 --> 00:02:31,100 We are going to, through errors that you have, exceed the request limit and we can use express middleware 26 00:02:31,100 --> 00:02:32,750 to implement that. 27 00:02:32,750 --> 00:02:37,430 You see how awesome middleware is and not all. 28 00:02:37,430 --> 00:02:42,290 We can use middleware to implement what is called data validation. 29 00:02:42,560 --> 00:02:49,490 So for the application that we built, we haven't implement what is called validation, whether the 30 00:02:49,490 --> 00:02:57,440 user is providing the right data or not, and we can use express middleware to implement data validation. 31 00:02:57,680 --> 00:03:05,270 And the cool part about Express middleware is that we can use you to implement any business logic. 32 00:03:05,270 --> 00:03:10,370 So if you understand middleware, you can do a lot of in your application. 33 00:03:10,490 --> 00:03:16,610 So let's say that if your account is on a starter account, then you can create, let's see, five posts 34 00:03:16,610 --> 00:03:17,810 or three posts. 35 00:03:18,080 --> 00:03:25,340 And if your account is a account, then we can allow you to create unlimited posts and we can get that 36 00:03:25,340 --> 00:03:28,430 one done using what is called medium well. 37 00:03:28,790 --> 00:03:37,130 The next video, let's talk more about how middleware works and the next middleware that we spoke about 38 00:03:37,130 --> 00:03:41,390 in the previous video, which is this next module. 39 00:03:41,420 --> 00:03:43,940 Let's get into that in the next video.