From majestic-rails
Implements state machines with AASM gem in Rails apps for workflow management. Covers transitions, guards, callbacks, error handling, and RSpec testing.
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/majestic-rails:aasm-coderThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
State machine patterns for managing workflow states in Rails.
State machine patterns for managing workflow states in Rails.
# Gemfile
gem "aasm", "~> 5.5"
class Order < ApplicationRecord
include AASM
aasm column: :status do
state :pending, initial: true
state :paid
state :processing
state :shipped
state :cancelled
event :pay do
transitions from: :pending, to: :paid
after do
OrderMailer.payment_received(self).deliver_later
end
end
event :process do
transitions from: :paid, to: :processing
end
event :ship do
transitions from: :processing, to: :shipped
end
event :cancel do
transitions from: [:pending, :paid], to: :cancelled
before do
refund_payment if paid?
end
end
end
end
order = Order.create!
order.pending? # => true
order.may_pay? # => true
order.pay! # Transition + callbacks
order.paid? # => true
order.may_ship? # => false (must process first)
order.aasm.events # => [:process, :cancel]
# Scopes created automatically
Order.pending
Order.paid.where(user: current_user)
event :pay do
transitions from: :pending, to: :paid, guard: :payment_valid?
end
def payment_valid?
payment_method.present? && total > 0
end
# Usage
order.pay! # Raises AASM::InvalidTransition if guard fails
order.pay # Returns false (no exception)
aasm do
# State callbacks
state :paid, before_enter: :validate_payment,
after_enter: :send_receipt
# Event callbacks
event :ship do
before do
generate_tracking_number
end
after do
notify_customer
end
transitions from: :processing, to: :shipped
end
end
Callback order:
before (event)before_exit (old state)before_enter (new state)after_exit (old state)after_enter (new state)after (event)event :approve do
transitions from: :pending, to: :approved, guard: :auto_approvable?
transitions from: :pending, to: :review, guard: :needs_review?
transitions from: :pending, to: :rejected # fallback
end
First matching guard wins.
# Safe (returns false on failure)
order.pay # => false if invalid
# Raises exception
begin
order.pay!
rescue AASM::InvalidTransition => e
Rails.logger.error("Invalid transition: #{e.message}")
end
# Check before transition
if order.may_pay?
order.pay!
end
RSpec.describe Order do
let(:order) { create(:order) }
it "starts in pending state" do
expect(order).to be_pending
end
describe "pay event" do
it "transitions to paid" do
expect { order.pay! }
.to change(order, :status).from("pending").to("paid")
end
it "sends payment received email" do
expect(OrderMailer).to receive_message_chain(:payment_received, :deliver_later)
order.pay!
end
end
describe "ship event" do
context "when pending" do
it "raises error" do
expect { order.ship! }.to raise_error(AASM::InvalidTransition)
end
end
context "when processing" do
before { order.update!(status: :processing) }
it "transitions to shipped" do
expect { order.ship! }
.to change(order, :status).to("shipped")
end
end
end
end
For multiple state machines, persistence options, and history tracking see:
references/aasm-patterns.mdevent-sourcing-coder - For recording domain events when state transitions should trigger notifications, webhooks, or audit trails.npx claudepluginhub majesticlabs-dev/majestic-marketplace --plugin majestic-railsImplements Rails business logic with ActiveInteraction operations and AASM state machines. Covers combined patterns, transactions, and routes to specialized skills.
Builds, tests, and debugs event-driven state machines in Laravel using EventMachine. Activates on state machine definitions, behaviors, test assertions, parallel states, delegation, timers, and endpoints.
Finite state machines, event sourcing, CQRS (Command Query Responsibility Segregation), and state modeling.