WEBVTT 00:05.850 --> 00:07.380 Hey, did everyone share? 00:07.380 --> 00:09.710 And welcome to another video of this section. 00:09.720 --> 00:11.250 I hope you are enjoying this course. 00:11.250 --> 00:13.350 If you are enjoying it even a tiny bit, let me know. 00:13.350 --> 00:16.050 And then Instagram share a story, click a photo or something. 00:16.050 --> 00:21.060 I would be really, really happy to see your feedback and it motivates me to create more awesome courses. 00:21.060 --> 00:23.910 So we have applied a lot from this strategy. 00:23.910 --> 00:27.570 We have seen that how we can register and check already registered users. 00:27.570 --> 00:30.780 Now the problem in front of us is to take care of the password. 00:30.900 --> 00:34.980 I can directly introduce you what the solution is, but I'm not going to do it like that. 00:34.980 --> 00:39.450 I will introduce you to all the possible use case scenario that can happen so that whenever you are 00:39.450 --> 00:41.340 designing any back end, you know what? 00:41.340 --> 00:45.870 All situation goes in and you find out that yes, all of them situations are absolutely correct. 00:45.870 --> 00:48.630 You can choose any path, so it is enough. 00:48.750 --> 00:52.800 Now we cannot avoid one thing which is getting introduced to the middleware. 00:52.980 --> 00:58.500 A lot of people believe that middleware is a concept of express JS or some routing concept, which is 00:58.500 --> 00:59.280 not true. 00:59.280 --> 01:04.890 Yes, it is being used quite a lot in the routing and express, but it is equally used in mongoose, 01:04.890 --> 01:08.070 other libraries, other frameworks and in other languages as well. 01:08.070 --> 01:09.720 Like Python and Java. 01:09.720 --> 01:12.270 This concept is whole in general. 01:12.270 --> 01:17.580 So that's why a lot of people actually adopted a lot of frameworks and libraries adapted by no mean. 01:17.580 --> 01:21.990 This doesn't mean that this is only a concept to JavaScript or only to Node.js. 01:21.990 --> 01:23.100 It is not like that. 01:23.220 --> 01:25.590 So first, let's understand what is the middleware? 01:25.620 --> 01:28.590 Now, middleware is something which happens in between in the middle. 01:28.620 --> 01:33.720 Yes, I know this is super easy, but let's elaborate it a little bit so that you understand it permanently 01:33.720 --> 01:35.310 for the fullest of all. 01:35.400 --> 01:38.250 Now in the middleware, let's go with a very simple example. 01:38.250 --> 01:42.540 In fact, a couple of them, let's just say you are in the office and you want to go to home. 01:42.540 --> 01:46.140 But this is a weekend and you don't want to directly go to home. 01:46.140 --> 01:48.060 You are going to go first to the bakery. 01:48.090 --> 01:53.790 You decided that I'll buy myself a pizza, probably a soft drink, and then I'll go to the home. 01:53.790 --> 01:56.670 So what you did there, you did something in between. 01:56.670 --> 02:00.120 And that's the whole idea of having a concept of middleware. 02:00.120 --> 02:05.790 You do something in between now you actually pass on after that or not, that's up to you. 02:05.790 --> 02:09.990 And the second example will give you more idea of what middleware possibly can do. 02:10.080 --> 02:14.010 You are in the office and this is a working hour probably Monday morning. 02:14.010 --> 02:17.820 And this is you are working into a marketing job or a field job. 02:17.820 --> 02:20.550 And in that you have to go through with couple of vendors. 02:20.550 --> 02:26.190 Now, these vendors are somebody who takes some material or raw material from your organization, and 02:26.190 --> 02:28.530 this is your day where you want to collect some money. 02:28.530 --> 02:33.570 So you go to the vendor and this vendor says, Hey, you take a check from us and you go to the bank 02:33.570 --> 02:34.830 to deposit that check. 02:34.830 --> 02:39.000 But there is also a possibility saying that this vendor doesn't give you a check, but rather gives 02:39.000 --> 02:39.810 you a cash. 02:39.810 --> 02:45.000 So in that case, you simply go ahead, go to your collection office and deposit that check so you can 02:45.000 --> 02:50.150 see in this case, the middle weight is heavily influencing you what you really should do next up. 02:50.160 --> 02:53.640 And if the vendor is not giving you anything, you should not proceed further. 02:53.640 --> 02:56.340 This is one way example, but this can also happen. 02:56.460 --> 03:01.350 So again, moving on to this same scenario, what it can happen, let's go ahead and take it to the 03:01.350 --> 03:02.640 technical side of it. 03:02.670 --> 03:07.710 Now, this is some kind of check or functionality that is injected in between what? 03:07.710 --> 03:08.400 In between? 03:08.400 --> 03:13.530 Yes, it can happen in the root as just we saw, but it can happen in the process of doing something 03:13.530 --> 03:18.270 like, for example, you want to save something into the database just before the save happen, do something 03:18.270 --> 03:20.550 or just after the save happen, do something. 03:20.550 --> 03:21.870 They are also middleware. 03:21.870 --> 03:24.930 So it doesn't mean that the middleware should happen only in between. 03:24.930 --> 03:27.150 It can happen just after that as well. 03:27.360 --> 03:31.680 Sometimes this can also be called as a life cycle event or life cycle hooks as well. 03:31.680 --> 03:36.330 Totally fine as a definition as long as you get the idea and what the concept in between. 03:36.330 --> 03:40.320 We are not in the phase that we should be fighting about what we are calling it. 03:40.320 --> 03:42.960 That's not what we are going to do doing up here. 03:43.110 --> 03:47.700 Now, since we are talking more about the Node.js friendly environment and especially Express and everything, 03:47.700 --> 03:50.280 you should also know about the next keyword. 03:50.280 --> 03:55.770 Now this keyword is really important if you're going to be writing any kind of middleware at all, let's 03:55.770 --> 04:01.110 go ahead and see what this keyword is responsible and how it is going to inject its functionality in 04:01.110 --> 04:03.420 the perspective of the web development. 04:03.810 --> 04:09.300 So let's just say a request comes in to you or your application and you decide that, hey, I am not 04:09.300 --> 04:13.770 going to allow this request is, by the way, to access the dashboard, probably an admin dashboard. 04:13.770 --> 04:16.470 So you have designed multiple functionality in between. 04:16.470 --> 04:20.970 You have said that, hey, this is a functionality or feature to check it whether you are logged in 04:20.970 --> 04:21.540 or not. 04:21.540 --> 04:25.020 So once you have checked that, then you have to use this keyword next. 04:25.020 --> 04:28.950 If you are not going to use this next keyword, it's not going to pass on through whatever next should 04:28.950 --> 04:29.940 happen now. 04:29.940 --> 04:30.900 What should happen next? 04:30.900 --> 04:37.530 Maybe another middleware, maybe another dashboard access or maybe three or four in between checks and 04:37.530 --> 04:38.670 then the access of dashboard. 04:38.670 --> 04:39.180 It can happen. 04:39.180 --> 04:41.280 Anything similar to the vendor operation? 04:41.280 --> 04:46.140 Maybe you are going to one vendor only and collecting cache and depositing maybe are going through five 04:46.140 --> 04:51.180 different vendors and then going to collect the cache or deposit the cache so this can happen. 04:51.180 --> 04:55.140 So in the first phase, we have decided that we will check whether the user is logged in or not. 04:55.140 --> 05:00.210 And in the second phase again since the next is there, that's only the reason why it is moving into 05:00.210 --> 05:01.110 the next phase. 05:01.110 --> 05:04.170 It says that, hey, I want to check whether you have an admin role or. 05:04.280 --> 05:07.580 A manager role and then only allow you to actually get that. 05:07.580 --> 05:11.450 So once this is all done, then only I'll allow you to access the dashboard. 05:11.450 --> 05:13.220 Probably you can have one more to check. 05:13.220 --> 05:15.590 Something else that you want to have a check. 05:15.590 --> 05:21.050 Whether you have created an account this year or after this year, I want to redirect to this dashboard 05:21.050 --> 05:22.070 or a modern dashboard. 05:22.070 --> 05:24.350 So it's totally up to you how you decide it. 05:24.350 --> 05:26.990 And this is how the basic minimum code looks like. 05:26.990 --> 05:31.760 Previously we were having this request and response, but now we also inject the next as a keyword. 05:31.760 --> 05:36.230 And once we have done with all the functionality, we actually go ahead and use the next. 05:36.230 --> 05:41.870 Now the last three double dots actually are the representation that nothing happens after the next is 05:41.870 --> 05:42.260 done. 05:42.260 --> 05:46.910 This means almost like sending a response or taking, Hey, take the control back from me. 05:46.910 --> 05:48.590 I don't know what should happen after that. 05:48.590 --> 05:50.090 And that's the whole idea. 05:50.090 --> 05:53.390 So this is the bare minimum basics of what middleware is. 05:53.390 --> 05:58.610 Once you understand this middleware is there, then we can actually go ahead and take down the situation 05:58.610 --> 06:00.530 of how we can take down the password. 06:00.530 --> 06:04.940 In the next video, I will walk you through with the two possible scenario that can happen. 06:04.940 --> 06:09.260 And then in the next one we are going to write the code to how to solve that problem. 06:09.260 --> 06:11.180 Let's go ahead and move on to the next video.