Reading version in controllers

[noble silo]

Hiya! 👋

I have a case where a controller method (endpoint) can have multiple versions. During the controller logic I will need to perform an action based on which version is in use. Anyone knows if its possible to read the version somehow?

Example:

class AnimalController {
  @Version(['dog', 'cat'])
  @Post()
  createAnimal() {
    if (version === 'cat') {
      // Meow
    }
  }
}

[ember adder]

import { SetMetadata } from '@nestjs/common';

export const VERSION_METADATA_KEY = 'versions';

export const Version = (versions: string[]) =>
  SetMetadata(VERSION_METADATA_KEY, versions);

class AnimalController {
  @Version(['dog', 'cat'])
  @Post()
  createAnimal() {
    const versions = Reflect.getMetadata(
      VERSION_METADATA_KEY, // <-- the key we defined earlier above
      AnimalController.prototype.createAnimal, // <-- current method
    );

    console.log(versions); // ['dog', 'cat']

    if (versions.includes('cat') {
      // Meow? :)
    }
  }
}

[frank harness]

I believe OP's want to use the versioning feature from nestjs, not its own decorator. Right, @noble silo ?

[ember adder]

yeah most likely, checking an static array doesn't make sense, mb

[frank harness]

and there's no abstraction to retrieve which version is being invoked

[noble silo]

Exactly 🙂 Essentially I have a method that will be used in two cases, and instead of creating a method for each case, I was hoping to just use the same and check on the version used.. I could have it as a route param also, but since its a spec implementation, it has to be part of the version and not just a route param (which would have been alot easier :D)

[frank harness]

you can open a feature request at https://github.com/nestjs/nest
that sounds reasonable since versioning is a "first-class citizen" in nest

[noble silo]

Yeah I also think it would be a good feature to have.. I'll set up a request when back at the job tomorrow 🙂 Thanks!

[meager forge]

@frank harness How would you propose we determine this during runtime? Or rather, how would we pass this information to the controller? Modify how the version filter returns the new routeHandler? https://github.com/nestjs/nest/blob/master/packages/core/router/router-explorer.ts#L204

[frank harness]

I'm not sure if it would be feasible (nor if it does makes sense) but I'm thinking on adding such info to the execution context obj (https://docs.nestjs.com/fundamentals/execution-context)

or maybe as a new parameter decorator
but I'd like to avoid adding new decorators

[meager forge]

The thing with the execution context is it wouldn't be available in the controller unless it's added rto the request itself