Juniper: Any way to auto-generate struct field resolvers, and also hand-write a custom one?

Created on 21 Jun 2019 · 5Comments · Source: graphql-rust/juniper

Is there a way to have all fields of a struct have auto-generated resolvers, as provided by #[derive(GraphQLObject)], but be able to custom-derive a few more, as can be done with graphql_object! macro?

Since the two techniques don't mix, it seems the only choice is to use graphql_object! macro, and hand-write all of the trivial resolvers along with the custom ones.

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hrbigelow

Most helpful comment

This is much wanted and there are multiple paths to this.

One option, merging definitions, is discussed in #182 .

My personally preferred way forward would be to apply a proc macro to a whole module to make this easy.

This is currently only possible on nightly with the proc_macro_hygiene feature.

I'd want us to have code like this and make it just work:

#[juniper::module]
mod graphql {
  #[derive(GraphQLObject)]
  struct MyType {

  }

  #[juniper::object]
  impl MyType {
    fn extra_resolver() -> bool { true } 
    ....
  }
}

theduke on 25 Jun 2019

👍3

All 5 comments

I don't believe there is. Happy to review a PR!

LegNeato on 25 Jun 2019

This is much wanted and there are multiple paths to this.

One option, merging definitions, is discussed in #182 .

My personally preferred way forward would be to apply a proc macro to a whole module to make this easy.

This is currently only possible on nightly with the proc_macro_hygiene feature.

I'd want us to have code like this and make it just work:

#[juniper::module]
mod graphql {
  #[derive(GraphQLObject)]
  struct MyType {

  }

  #[juniper::object]
  impl MyType {
    fn extra_resolver() -> bool { true } 
    ....
  }
}

theduke on 25 Jun 2019

👍3

Hi Christian,

That's great to hear there is interest in this. At the moment my macro
writing skills are not up to the task, but if that changes, I'll try to do
it. Incidentally, I did also try to write another unrelated macro, but
noticed that it doesn't work when called from within the graphql_object!()
call.

Cheers,

Henry

On Mon, Jun 24, 2019 at 7:38 PM Christian Legnitto notifications@github.com
wrote:

I don't believe there is. Happy to review a PR!

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