defmodule Absinthe.Plugin do
@moduledoc """
Plugin Behaviour
Plugins are an additional set of callbacks that can be used by module based
middleware to run actions before and after resolution, as well as add additional
phases to run after resolution
"""
@type t :: module
@doc """
callback to setup the resolution accumulator prior to resolution.
NOTE: This function is given the full accumulator. Namespacing is suggested to
avoid conflicts.
"""
@callback before_resolution(execution :: Absinthe.Blueprint.Execution.t()) ::
Absinthe.Blueprint.Execution.t()
@doc """
callback to do something with the resolution accumulator after
resolution.
NOTE: This function is given the full accumulator. Namespacing is suggested to
avoid conflicts.
"""
@callback after_resolution(execution :: Absinthe.Blueprint.Execution.t()) ::
Absinthe.Blueprint.Execution.t()
@doc """
callback used to specify additional phases to run.
Plugins may require additional resolution phases to be run. This function should
use values set in the resolution accumulator to determine
whether or not additional phases are required.
NOTE: This function is given the whole pipeline to be inserted after the current
phase completes.
"""
@callback pipeline(
next_pipeline :: Absinthe.Pipeline.t(),
execution :: Absinthe.Blueprint.Execution.t()
) ::
Absinthe.Pipeline.t()
@doc """
Returns the list of default plugins.
"""
def defaults() do
[Absinthe.Middleware.Batch, Absinthe.Middleware.Async]
end
@doc false
def pipeline(plugins, exec) do
Enum.reduce(plugins, [], fn plugin, pipeline ->
plugin.pipeline(pipeline, exec)
end)
|> Enum.dedup()
|> List.flatten()
end
end