Proposal for shared params

[dspaeth-faber]

Like discussed in #716 I would suggest this DSL for shared params instead of using Helpers.

[dblock]

I am not in love with the name include_params. It seems that you would want to use all kinds of things, params being one of them. I'd like to be able to write use pagination.

I also don't love the SharedParams name, I think maybe it should just be Params?

[dspaeth-faber]

Yeah, it's only a starting point for discussion. Without seeing some code it's difficult some times to discuss things. include_params is only needed because all of the imbue thing like it works today.

In theorie it should be possible to use use inside the params block only. But then it would not be possible to use the same name multiple times within different scopes.

[dm1try]

@dspaeth-faber, @dblock which problem does PR solve? How do you use a "shared params" feature?

from here

In current implementation helper module can include "Enpoint-Instance" and "API-Class" helpers through single syntax helpers.

[dspaeth-faber]

This PR is porposal to solve the semantic gap. Helpers extend an Enpoint instance. Params work on API-Class level. This seems like a missmatch.

shared_params provide a global registry for shared parameters and make it sematicaly clear what is meant.

Furthor more you can extend your module from Grape::SharedParams and use this module together with include_params. This makes it more obvoius what is happening.

Using helpers ParamsModule seem's not obvious to me. That some thing is not ok can you see within the original Helpers module. The methods within this module have only one purpose provide access to the API-Class settings to inject new parameters and they come into play during "compile time". Other DSL methods from API class level are not available.

In my point of view there should a distinction between Helper modules and other DSL methods.
Helpers are the only way to provide Methods to your Endpoint instance and this should be all their
responsibilities.

[dm1try]

@dspaeth-faber fair enough:ok_hand:

[dblock]

I am still 50/50 about this. I understand your point @dspaeth-faber, it makes sense. But something doesn't feel right here. I would like more opinions.

[dmitry]

Why is there are include_params required? Why not simply:

        shared_params :pagination_more do
          optional :per_page, type: Integer
        end

[dm1try]

@dmitry good point 👍

[dm1try]

So @dblock there are no other opinions :)
I can push this forward and finish the PR if needed.

[dblock]

Thanks @dm1try