nest Add support for dynamically generating URLs

Is there an existing issue that is already proposing this?

[x] I have searched the existing issues

Is your feature request related to a problem? Please describe it

I am wondering how to generate URLs in NestJS. For example in a Controller or Service. Something like in symfony routing. I found that there is an external package Nest-URL-Generator but it isn't that popular and has not many downloads. I am wondering how all the users of NestJS generate URLs in their application without hardcoding them? The Github API for example has at their API entrypoint a list full of URLs for their resources https://api.github.com/ I want to do the same, but without hardcoding all the URLs. Because if one URL changes, I would have to edit it everywhere in the application.

Describe the solution you'd like

So I want an UrlGeneratorService where you can generate a URL for a specific controller with method and params. Without that it's for example impossible to develop a RestAPI. Or for example if you have a controller method for creating users: UserController.createUser() After successfully creating the user, I have to send back the URL of that user resource in the location header, so I want something like: urlGenerator.generateUrl(UserController.name, UserController.prototype.getUser.name, { uuid: uuid }) or with named Controller methods where you can give a controller method a name and then route to that name: urlGenerator.generateUrl('getUser', { uuid: uuid })

Or in Rest APIs you often have to send back links to other resource endpoints. I don't want to hardcode that URLs. I want to generate that URLs dynamically.

This is a very basic functionality and every framework has it, so I am really wondering how to generate URLs in NestJS.

Teachability, documentation, adoption, migration strategy

https://symfony.com/doc/current/routing.html#generating-urls-in-controllers

What is the motivation / use case for changing the behavior?

I want that NestJS has the same basic features that other popular frameworks also have.

Aug 03 '22 14:08 zetti-caletti

looks like that lib is abandoned :disappointed:

Another thing we could do is: provide reliable ways to retrieve the metadata needed for such task, ie.,

retrieve all routes for a given controller
retrieve all routes for a given controller's method

so the dev doesn't need to use Reflect.metadata and so on.

Maybe under the DiscoverModule or RouterModule

https://github.com/nestjs/nest/blob/721372f0c6b1e64a2c9a6a3dbc5ef5e90fa5bd40/packages/core/discovery/discovery-module.ts#L8-L12

Aug 03 '22 22:08 micalevisk

This feature should return a url like

/getUsers?randomParam=randomValue

Or return the app base url too? Because if needs the base url I think can be more complex because u can change the url on infrastructure 🤔 Maybe have a optional param called baseUrl?

Aug 05 '22 22:08 wesleymatosdev

Another question @zetti-caletti, u are thinking about something under the RouterModule for example or something more specific?

Aug 05 '22 23:08 wesleymatosdev

This feature should return a url like

/getUsers?randomParam=randomValue

Or return the app base url too? Because if needs the base url I think can be more complex because u can change the url on infrastructure thinking Maybe have a optional param called baseUrl?

Yes, but you should also have the opportunity to replace the slugs in the URLs. So e. g. /users/{uuid}/?sort=xxx Yes I think the best would be under the RouterModule. Hold on, I'm making a PR and then we can discuss or make further changes.

Aug 23 '22 15:08 zetti-caletti

@micalevisk @ologbonowiwi @kamilmysliwiec I forked the project, created a branch and added the feature with my ideas. It was hard but I liked it because I never saw the internals of nestjs. I created a separate UrlGeneratorModule and you can configure the absoluteUrl there. I added a RoutingTable service where the routes are stored during bootstrap and then can be fetched from within the UrlGenerator. Didn't knew how to get these routes otherwise. I also added a sample. These are just thoughts, so I didn't added tests. Please review and then we can discuss. https://github.com/zetti-caletti/nest/tree/feature/url-generator

Thanks

Aug 26 '22 02:08 zetti-caletti

feel free to make a draft PR

would be easier to discuss, I guess

Aug 26 '22 02:08 micalevisk

If you need a routing table, you could just extend the existing HTTP adapter (be it ExpressAdapter or FastifyAdapter), override HTTP-related methods (get/post/patch/etc) and just put routes alongside their handlers into a collection (map?).

Sep 19 '22 13:09 kamilmysliwiec

Ok, how to extend the HTTP adapter? But why don't you make this part of the framework? If YOU have to write for example a rest api, how would you generate the links without hardcoding them? I think every framework has tools to generate the urls for controller methods except NestJS? Another example:

return {
    data: post,
    links: {
        self: {
            href: https://www.example.com/api/v2/posts/${post.uuid}
        }
    }
}

Oct 09 '22 23:10 zetti-caletti

as the http adapter is a concrete JS class (namely ExpressAdapter and FastifyAdapter). You could extend it like any other class and pass it to the NestFactory.create

I like the ideia of having such feature into the fw but, to me, the proposed solution looks to unflexible and opinative, and a bit hard to follow.

I'm thinking on making something with a simple API that still could be used as a building block of something fancy that the end dev could implement...

Oct 10 '22 00:10 micalevisk

I was thinking of something like this:

@Controller({
  path: 'posts',
  version: '2'
})
export class AppController {
  @Get()
  fetchPost(
    @Param('post_id') postId: string
  ) { ... }
}

// This will generate:
// http://localhost:3000/api/v2/posts/123
this.urlGeneratorService.generateUrl({
  controller: AppController,
  controllerMethod: 'fetchPost',
  version: '2', // optional. But raise an exception at runtime if not supplied if there's no NEUTRAL version.
  params: { // optional as there's no way to know if `AppController#fetchPost` has `@Param` at build time.
    'post_id': 123,
    // Should raise an exception if `post_id` is not supplied as we know it must exists at runtime.
  },
})

and everything must be strongly typed as much as we could.

Oct 10 '22 00:10 micalevisk

as the http adapter is a concrete JS class (namely ExpressAdapter and FastifyAdapter). You could extend it like any other class and pass it to the NestFactory.create

I like the ideia of having such feature into the fw but, to me, the proposed solution looks to unflexible and opinative, and a bit hard to follow.

I'm thinking on making something with a simple API that still could be used as a building block of something fancy that the end dev could implement...

I am open for new proposals, but why looks my proposal too unflexible and hard to follow? It's one method call: urlGenerator.generateUrl('getPost', { uuid: uuid })

The difference is only that in your proposal you give the controller and controller method as a param and my mine I give the method a name and get the URL by route name?!

Undependent how the implementation is done in the end, this frameworks needs definitely such a feature. And again, this framework has over 1 Million downloads per week. I am wondering how all this users build their URLs?! I mean it isn't only for REST APIs. If you want for example render a html view and embed there a link, you also have to generate the URL for that link. But how does all the people do this? Hardcoding all links? I'm surprised that I am the only one who needs this or am I missing something? :D

@micalevisk You can also do a PR, maybe your solutions gets accepted and integrated in the framework :)