AshCommanded.Commanded.Middleware.BaseMiddleware (AshCommanded v0.1.0)

Base module for implementing command middleware in AshCommanded.

This module provides default implementations and helper functions for common middleware patterns. By using this module, you can implement only the callbacks you need while inheriting sensible defaults.

Examples

defmodule MyApp.LoggingMiddleware do
  use AshCommanded.Commanded.Middleware.BaseMiddleware
  
  @impl true
  def before_dispatch(command, context, next) do
    # Log command being dispatched
    IO.inspect(command, label: "Dispatching command")
    next.(command, context)
  end
  
  @impl true
  def after_dispatch({:ok, result} = success, command, _context) do
    # Log successful execution
    IO.inspect(result, label: "Command succeeded")
    success
  end
  
  def after_dispatch({:error, reason} = error, command, _context) do
    # Log failed execution
    IO.inspect(reason, label: "Command failed")
    error
  end
end

Default Implementations

By default, this module:

Passes the command and context unchanged to the next middleware
Returns the result from the command handler unchanged

Summary

Functions

__using__(opts)

Using this module will implement the CommandMiddleware behavior.

apply_middleware(middleware, command, context, final_handler)

Helper to apply a list of middleware to a command.

Functions

using(opts)

(macro)

Using this module will implement the CommandMiddleware behavior.

apply_middleware(middleware, command, context, final_handler)

@spec apply_middleware(
  middleware :: [module()],
  command :: struct(),
  context :: map(),
  final_handler :: (struct(), map() -> {:ok, any()} | {:error, any()})
) :: {:ok, any()} | {:error, any()}

Helper to apply a list of middleware to a command.

Parameters

middleware - List of middleware modules to apply
command - The command to process
context - The context for the command
final_handler - Function to call after all middleware has been applied

Examples

apply_middleware(
  [LoggingMiddleware, ValidationMiddleware],
  %MyCommand{},
  %{},
  fn cmd, ctx -> {:ok, dispatch_command(cmd)} end
)