The Resolve middleware will fetch a resource and mark the Absinthe.Resolution as resolved.

It expects a return signature of: {any | {:ok, any}, {:errors, any}

Speakeasy.Resolve has 4 forms:

No arguments

Providing no arguments to the callback will simply return the resource retreived by Speakeasy.LoadResource if it was called:

field :post, type: :post do
  arg(:id, non_null(:string))
  middleware(Speakeasy.Authn)
  middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
  middleware(Speakeasy.Authz, {Posts, :get_post})
  middleware(Speakeasy.Resolve)
end

0 arity function

Functions with an arity of 0 will simply be called:

field :post, type: :post do
  arg(:id, non_null(:string))
  middleware(Speakeasy.Authn)
  middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
  middleware(Speakeasy.Authz, {Posts, :get_post})
  middleware(Speakeasy.Resolve, fn() -> MyApp.Posts.something() end)
end

1 arity function

Functions with an arity of 1 will receive the Absinthe arguments:

field :post, type: :post do
  arg(:id, non_null(:string))
  middleware(Speakeasy.Authn)
  middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
  middleware(Speakeasy.Authz, {Posts, :get_post})
  middleware(Speakeasy.Resolve, fn(attrs) -> MyApp.Posts.get_post(attrs) end)
end

2 arity function

This is a good form to use when creating a resource if your code takes the user in additional to the attributes.

Functions with an arity of 2 will receive the graph will receive the Absinthe arguments and the SpeakEasy current user:

field :post, type: :post do
  arg(:id, non_null(:string))
  middleware(Speakeasy.Authn)
  middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
  middleware(Speakeasy.Authz, {Posts, :create_post})
  middleware(Speakeasy.Resolve, fn(attrs, user) -> MyApp.Posts.create_post(attrs, user) end)
end

3 arity function

This is a good form to use when needing to update a resource.

Functions with an arity of 3 will receive the graph will receive the resource retreived by Speakeasy.LoadResource (if it was called), the Absinthe arguments, and the SpeakEasy current user:

field :post, type: :post do
  arg(:id, non_null(:string))
  middleware(Speakeasy.Authn)
  middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
  middleware(Speakeasy.Authz, {Posts, :update_posts})
  middleware(Speakeasy.Resolve, fn(resource, attrs, _user) -> MyApp.Posts.update_post(resource, attrs) end)
  # middleware(Speakeasy.Resolve, &MyApp.Posts.update_posts/3)
end