1 00:00:06,100 --> 00:00:07,660 Welcome back. 2 00:00:07,689 --> 00:00:12,820 In this video, let's see how authentication works. 3 00:00:12,820 --> 00:00:14,950 So let's get started. 4 00:00:15,610 --> 00:00:16,680 All right. 5 00:00:16,690 --> 00:00:25,720 First of all, let's say that we have this particular client or user who is trying to use our application, 6 00:00:25,900 --> 00:00:31,720 and definitely the user is going to use a browser in this case, Google Chrome. 7 00:00:32,290 --> 00:00:39,430 So as soon as the user open our application, a form will be open to the person. 8 00:00:39,640 --> 00:00:43,690 But before logging in, let's see what goes on here. 9 00:00:44,020 --> 00:00:52,510 First, we need a server where the user is going to make a request to and for this particular server. 10 00:00:52,630 --> 00:00:59,800 Let's say we build this server using Node.js and definitely having server alone. 11 00:00:59,800 --> 00:01:02,530 We need a way to store data. 12 00:01:02,620 --> 00:01:05,530 That is why we need data source. 13 00:01:05,530 --> 00:01:09,250 And for this case it's going to be MongoDB. 14 00:01:09,430 --> 00:01:13,030 Now we have these three things in the mix. 15 00:01:13,300 --> 00:01:15,580 So now let's look at the flow. 16 00:01:15,940 --> 00:01:21,460 When a user visit our URL, a form will be open for the user. 17 00:01:22,300 --> 00:01:28,120 So as soon as the user enter the login credentials, let's say email and password. 18 00:01:28,150 --> 00:01:32,890 The first point is that the data will be sent to our server. 19 00:01:33,490 --> 00:01:42,490 Then the server will also send the request to the database to find if this particular user details is 20 00:01:42,490 --> 00:01:44,800 really inside this database. 21 00:01:45,070 --> 00:01:52,870 So if it founds, for example, if the username here is a and then inside the DB is A and the password 22 00:01:52,870 --> 00:01:58,030 is B, and inside DB the password is B, it means that it matches. 23 00:01:58,210 --> 00:02:05,590 So we are going to implement that logic inside our server where we are going to check the user data 24 00:02:05,590 --> 00:02:08,590 against the data inside the database. 25 00:02:08,889 --> 00:02:14,860 So once the user logging credential is wrong, then the process will exit. 26 00:02:15,400 --> 00:02:21,040 So you will see what is called login failed or invalid login credentials. 27 00:02:21,790 --> 00:02:30,430 In this way, the response was sent from the client to the server and server to MongoDB, and then MongoDB 28 00:02:30,430 --> 00:02:32,920 will send the response back to the server. 29 00:02:32,950 --> 00:02:39,130 The server response said, Hey, MongoDB says that we don't know this particular email, so you are 30 00:02:39,130 --> 00:02:40,750 not authorized to log in. 31 00:02:41,020 --> 00:02:45,040 But let's say that the user provides the right logging credentials. 32 00:02:45,040 --> 00:02:53,800 Then the database response we give you to our server and our services that Hey, user MongoDB says that 33 00:02:53,800 --> 00:02:58,570 your data are inside the database so you can go ahead and log in. 34 00:02:58,750 --> 00:03:02,120 So at this point, the user has been, what, log in. 35 00:03:02,140 --> 00:03:10,120 So in a nutshell, when entering your record into our server is going to check if the record the user 36 00:03:10,120 --> 00:03:13,420 is trying to enter is inside our database. 37 00:03:13,450 --> 00:03:16,930 If it is there, then the user will go ahead and then log in. 38 00:03:16,960 --> 00:03:19,670 Otherwise, we're not return error. 39 00:03:19,690 --> 00:03:23,880 So this is a basic flow and this is what we are going to implement. 40 00:03:23,890 --> 00:03:29,440 So where we are going to work on is inside our server here. 41 00:03:30,010 --> 00:03:30,640 All right. 42 00:03:30,640 --> 00:03:37,000 So in the next video, let's get started with the low level authentication where a user is going to 43 00:03:37,000 --> 00:03:40,930 log in with a plain email and then password or username. 44 00:03:40,960 --> 00:03:43,300 Let's get into that in the next video.