Dex::Operation

Operations are service objects that encapsulate a single business action. They bring typed properties, error handling, transactions, callbacks, and more – all in a clean, composable API.

Basic anatomy

class CreateUser < Dex::Operation
  prop :name, String
  prop :email, String

  def perform
    User.create!(name: name, email: email)
  end
end

Every operation has a perform method that contains the business logic. Properties declared with prop become the operation's inputs – typed, validated, and available as instance methods.

Calling an operation

# Class-level shorthand
user = CreateUser.call(name: "Alice", email: "[email protected]")

# Two-step form (needed for .safe and .async)
user = CreateUser.new(name: "Alice", email: "[email protected]").call

Both forms do the same thing: instantiate with properties, then execute the pipeline. The two-step form is required when chaining modifiers like .safe.call or .async.call.

What happens when you call

Behind the scenes, call doesn't just run perform – it runs it through a pipeline of wrapper steps. The default pipeline, from outermost to innermost:

result > lock > transaction > record > rescue > callbacks > perform

Each step wraps the next one. Transactions wrap your database calls. Callbacks hook into the lifecycle. Errors are caught and converted. You get all of this out of the box, and every step can be configured or disabled.

Return values

Whatever perform returns is the operation's return value:

class FullName < Dex::Operation
  prop :first, String
  prop :last, String

  def perform
    "#{first} #{last}"
  end
end

FullName.call(first: "John", last: "Doe")  # => "John Doe"

You can also halt early with success! or error! – see Error Handling for the full story.

Inheritance

Operations are regular Ruby classes, so inheritance works as expected:

class BaseOperation < Dex::Operation
  transaction false  # disable transactions for all children
end

class ReadOperation < BaseOperation
  prop :id, Integer

  def perform
    Record.find(id)
  end
end

Settings, callbacks, error declarations, and pipeline steps all inherit from parent classes. Child classes can override or extend anything.

What's next

• Properties & Types – defining inputs with type validation
• Error Handling – error!, assert!, success!, rescue_from
• Callbacks – before, after, around
• Transactions – automatic database transactions