absinthe v0.2.2 Absinthe.Type.FieldDefinition

Used to define a field.

Usually these are defined using the Absinthe.Type.Definitions.fields/1 convenience function.

See the t type below for details and examples of how to define a field.

Summary

Types

t()

The configuration for a field

Types

t :: %{name: binary, description: binary | nil, type: Absinthe.Type.identifier_t, deprecation: Absinthe.Type.Deprecation.t | nil, args: %{binary | atom => Absinthe.Type.Argument.t} | nil, resolve: (any, %{binary => any} | nil, Absinthe.Type.ResolveInfo.t | nil -> Absinthe.Type.output_t) | nil}

The configuration for a field

:name - The name of the field, usually assigned automatically by the Absinthe.Type.Definitions.fields/1 convenience function.
:description - Description of a field, useful for introspection.
:deprecation - Deprecation information for a field, usually set-up using the Absinthe.Type.Definitions.deprecate/2 convenience function.
:type - The type the value of the field should resolve to
:args - The arguments of the field, usually created by using the Absinthe.Type.Definitions.args/1 convenience function.
resolve - The resolution function. See below for more information.

Resolution Functions

Default

If no resolution function is given, the default resolution function is used, which is roughly equivalent to this:

{:ok, Map.get(parent_object, field_name)}

This is commonly use when listing the available fields on a Absinthe.Type.Object that models a data record. For instance:

@absinthe :type
def person do
  %Absinthe.Type.Object{
    description: "A Person"
    fields: fields(
      first_name: [type: :string],
      last_name: [type: :string],
    )
  }
end

Custom Resolution

When accepting arguments, however, you probably need do use them for something. Here’s an example of definining a field that looks up a list of users for a given location_id:

def query do
  %Absinthe.Type.Object{
    fields: fields(
      users: [
        type: :person,
        args: args(
          location_id: [type: non_null(:integer)]
        ),
        resolve: fn
          %{location_id: id}, _execution ->
            {:ok, MyApp.users_for_location_id(id)}
        end
      ]
    )
  }
end

Custom resolution functions are passed two arguments:

A map of the arguments for the field, filled in with values from the provided query document/variables.
An Absinthe.Execution struct, containing the complete execution context (and useful for complex resolutions using the resolved parent object, etc)