Custom Directive and specifying the same on a Field and Type

I’ve tried looking at the documentation to figure out how to accomplish this but got no where.

How do I define a schema like this using Graphene?

directive @unique(
  info: String = "Blah blah"
) on FIELD_DEFINITION | ENUM_VALUE

directive @ignore(
  info: String = Blah blah"
) on OBJECT

type ExampleType @ignore(info: "Blah"){
  newField: String
  oldField: String @unique(info: "Blah")
}

[prashanthellina]

@jkimbo Thank you for the confirmation. I thought I was missing something. I believe there is merit in implementing directives as I find that a good way to signal behavior formally (rather than in comments) to both the user of the schema/service and the implementer of the resolver logic.

I quite liked the way that prisma (https://www.prisma.io/) uses directives to provide more expressiveness when using the SDL to describe ORM like interactions with a database.

For the moment, I am exploring using GraphQLS2S for defining the schema in an SDL superset (that support inheritance, generics etc to help reduce verbosity) and then transpiling it to standard SDL. After I have the final schema, I am using ariadne to implement the actual resolver logic.

[jkimbo]

@prashanthellina thanks for your patience. So I’ve looked into this a bit more and it looks like it’s not possible to apply directives on a field/object level. This is a conscious limitation of the reference GraphQL server implementation graphql-js. You can read more about the reasoning here: https://github.com/graphql/graphql-js/pull/746#issuecomment-301554231 and follow the ongoing discussion about it here: https://github.com/graphql/graphql-js/issues/1343

The relevant comments from leebyron are:

Right now directives are purely a feature of the GraphQL language and IDL, so a schema not created using IDL definitionally won’t contain directives. When building a schema in code, you have the full power of the host programming environment, so directives shouldn’t be necessary. Directives are a tool for supplying additional intent to be later interpreted by the host programming environment.

and

Directives are purely a feature of the GraphQL language and are not part of type definitions - this is because different tools will use and interpret directives in different ways.

(there is also a great long comment which explains things in detail)

Since Graphene is based on graphql-core which is a direct port of the graphql-js implementation, support for directives on fields/objects won’t happen until that support is available in graphql-js.

I hope that’s helpful. You might also want to checkout ariadne which is an alternative way of building a GraphQL server using the SDL.

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I’m going to create an new issue to document adding custom directives to the schema and then close this one.