GreenFairy.Schema (GreenFairy v0.3.0)

Schema assembly with graph-based type discovery.

Automatically discovers types by walking the type graph from your root query/mutation/subscription modules.

Basic Usage

defmodule MyApp.GraphQL.Schema do
  use GreenFairy.Schema,
    query: MyApp.GraphQL.RootQuery,
    mutation: MyApp.GraphQL.RootMutation,
    subscription: MyApp.GraphQL.RootSubscription
end

The schema will automatically discover all types reachable from your roots.

Inline Root Definitions

Or define roots inline:

defmodule MyApp.GraphQL.Schema do
  use GreenFairy.Schema

  root_query do
    field :health, :string do
      resolve fn _, _, _ -> {:ok, "ok"} end
    end
  end

  root_mutation do
    field :noop, :boolean do
      resolve fn _, _, _ -> {:ok, true} end
    end
  end
end

Options

:query - Module to use as root query (or use root_query macro)
:mutation - Module to use as root mutation (or use root_mutation macro)
:subscription - Module to use as root subscription (or use root_subscription macro)
:repo - Ecto repo module for database operations and Node resolution
:global_id - Custom GlobalId implementation (defaults to GreenFairy.GlobalId.Base64)
:dataloader - DataLoader configuration
- :sources - List of {source_name, repo_or_source} tuples

Custom Global IDs

You can implement custom global ID encoding/decoding:

defmodule MyApp.CustomGlobalId do
  @behaviour GreenFairy.GlobalId

  @impl true
  def encode(type_name, id), do: # your encoding

  @impl true
  def decode(global_id), do: # your decoding
end

use GreenFairy.Schema,
  query: MyApp.RootQuery,
  repo: MyApp.Repo,
  global_id: MyApp.CustomGlobalId

Type Discovery

Types are discovered by walking the graph from your root modules:

Start at Query/Mutation/Subscription modules
Extract type references from field definitions
Recursively follow references to discover all reachable types
Only import types actually used in your schema

This means:

Types can live anywhere in your codebase
Unused types are not imported
Clear dependency graph
Supports circular references

Summary

Functions

resolve_type_for(value, struct_mapping)

Generates resolve_type function for an interface based on discovered implementors.

root_mutation(list)

Define inline mutation fields for this schema.

root_query(list)

Define inline query fields for this schema.

root_subscription(list)

Define inline subscription fields for this schema.

Functions

resolve_type_for(value, struct_mapping)

Generates resolve_type function for an interface based on discovered implementors.

This can be called manually or used by the schema to auto-generate resolve_type functions for interfaces.

Example

def resolve_type(value, _) do
  GreenFairy.Schema.resolve_type_for(value, %{
    MyApp.User => :user,
    MyApp.Post => :post
  })
end

root_mutation(list)

(macro)

Define inline mutation fields for this schema.

root_mutation do
  field :noop, :boolean do
    resolve fn _, _, _ -> {:ok, true} end
  end
end

root_query(list)

(macro)

Define inline query fields for this schema.

root_query do
  field :health, :string do
    resolve fn _, _, _ -> {:ok, "ok"} end
  end
end

root_subscription(list)

(macro)

Define inline subscription fields for this schema.

root_subscription do
  field :events, :event do
    config fn _, _ -> {:ok, topic: "*"} end
  end
end