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‫In this lecture, things will start

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‫to get a bit more advanced.

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‫And that is because we'll now create multiple routers

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‫and use a process called mounting.

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‫So let's see how all that works.

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‫Now, before doing any of that, let's keep in mind

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‫that the ultimate goal will be to separate all the code

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‫that we have in this file into multiple files.

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‫So what I want, is to have one file

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‫that only contains all of these routes

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‫then I want to have another file,

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‫which has the routes for the users.

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‫I will also want to have a file which contains the handlers

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‫only for the users and then also one file

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‫that will contain all the handlers for the tours, okay?

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‫And so that's actually what we're gonna do

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‫in the next lecture.

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‫But in order to be able to do that,

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‫we actually need to now create one separate router

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‫for each of our resources.

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‫So, let's go back to our routes here and so right now,

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‫we can say that all our routes, so these four routes here,

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‫we can say that they're all kind of

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‫on a same router, okay?

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‫And the router, is this app object.

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‫But if we want to separate these routes

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‫into different files, so again,

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‫one file for these two routes

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‫and one file for these two routes,

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‫then the best thing to do, is to create one router

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‫for each of the resources, okay?

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‫And so, this is how we're gonna do.

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‫It's actually not that complicated,

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‫but you will have to wrap your head

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‫around a couple of concepts, okay?

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‫So, let's start by saying,

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‫const tourRouter is equal to express.Router.

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‫Okay, so just like this,

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‫we create a new router and save it into this variable.

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‫Alright, and so now let's use that router

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‫for these two routes.

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‫So here we use it instead of app.

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‫Alright, so now we have two router and then route

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‫and then of course, the get and the post routes

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‫on that router.

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‫Now, how do we actually connect this new router

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‫with our application?

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‫Well, we'll use it as middleware, alright?

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‫And so that is because, this new modular tool router here,

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‫is actually a real middleware, alright?

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‫And so we can say, (keyboard typing),

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‫app.use, and then the route but let's keep that for later.

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‫So we can use, the tourRouter on our application

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‫and where do we want to use the tourRouter?

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‫Well, we want to use it on,

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‫/api/version one/tours, okay?

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‫So again, this tourRouter here, is a real middleware.

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‫And we want to use that middleware for this specific route.

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‫Okay, and so we use app.use

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‫and specify the middleware function, which is this router,

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‫then we specify the the route so the URL,

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‫for which, we actually want to use that middleware, okay?

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‫And so just like this,

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‫we created basically a sub application, okay?

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‫Now, there's just one thing

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‫that we really need to change here,

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‫which is these routes in here, okay?

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‫So let me change this here, and then explain

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‫why it has to be this way.

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‫So here, we only want the route,

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‫and in here, we only want the id, okay?

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‫Now, why is that?

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‫Well, it's because this tourRouter middleware,

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‫only runs on this route here anyway, okay?

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‫And so once we are in the router,

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‫then we already are at this route.

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‫So at our tourRoute, and so this first route

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‫that we had to before, we only want to run it as,

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‫api/version one/tours

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‫and so that is what this route here now means, okay?

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‫So it's basically the route of this URL, okay?

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‫So is this small mini application, alright?

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‫So, actually, when we create a router system like this,

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‫we actually say that we kind of create a small sub app

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‫for each of these resources, okay?

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‫So this is the route of or mini application,

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‫which is again, at /tours, Okay?

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‫And then the second route, is at /id, right?

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‫And that's because, before,

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‫it was at tours /id, so it was all of this.

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‫So like this, but now, this URL here

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‫is already in our kind of parent route up here, right?

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‫So let's say that we have an incoming request now

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‫for /api/version one /tours/version id.

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‫So the request goes into the middleware stack

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‫and when it hits this line of code here,

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‫it will match this URL here, right?

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‫So it will match this route and therefore

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‫or two router middleware function will run.

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‫So or two router is this sub application that we created,

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‫which in turn has its own routes, okay?

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‫And if the request was for /id, well,

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‫then it will inside our mini app,

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‫hit this route here, right?

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‫And finally, of course,

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‫it will run one of these handles here,

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‫depending on the method that was used.

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‫So I hope that made sense.

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‫And so let's now actually go ahead and do the same

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‫for all users, alright?

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‫So, I will go ahead and create another router here,

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‫(keyboard typing) called, the userRouter,

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‫and then just like before, it's express.Router

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‫not like that, yeah.

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‫Okay, so use a router,

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‫and then we need to do the same process as here.

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‫And by the way, this is called mounting the router, okay?

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‫So mounting a new router on a route, basically, okay?

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‫So we have now users and here user.

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‫And actually, mounting the routers,

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‫has to come after all of these definitions

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‫or at least after we declared a variable, right?

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‫So we cannot use the routers

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‫before we actually declare them.

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‫Okay, now all we need to do is to go ahead

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‫and also change the routes in here.

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‫And so just like before, if there is now a request

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‫for /api/version one/users/id,

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‫the request will enter the middleware stack

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‫and when it hits this middleware here,

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‫it will run the user router,

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‫because this route here is matched, okay?

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‫And so then it enters the user router

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‫and again, just like before,

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‫this error is the route basically in our sub application,

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‫and this here, is the entire URL/id, okay?

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‫Does that make sense?

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‫So before moving on,

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‫let's actually test if this still works.

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‫So, let's get all the tours here and indeed, it does.

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‫So everything still works to the same with the users

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‫and also that still works.

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‫So we did all these changes and decode the works,

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‫meaning that our two new routers are correctly mounted.

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‫Alright, and with that, we are ready to actually separate

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‫or different routers now into different files.

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‫And that we will do right in the next lecture.