Domainic::Command

A robust implementation of the Command pattern for Ruby applications, providing type-safe, self-documenting business operations with standardized error handling and composable workflows.

Tired of scattered business logic and unclear error handling? Domainic::Command brings clarity to your domain operations by:

• Enforcing explicit input/output contracts with type validation
• Providing consistent error handling and status reporting
• Enabling self-documenting business operations
• Supporting composable command workflows
• Maintaining thread safety for concurrent operations

Quick Start

class CreateUser
  include Domainic::Command

  # Define expected inputs with validation
  argument :login, String, "The user's login", required: true
  argument :password, String, "The user's password", required: true

  # Define expected outputs
  output :user, User, "The created user", required: true
  output :created_at, Time, "When the user was created"

  def execute
    user = User.create!(login: context.login, password: context.password)
    context.user = user
    context.created_at = Time.current
  end
end

# Success case
result = CreateUser.call(login: "user@example.com", password: "secret123")
result.successful? # => true
result.user       # => #<User id: 1, login: "user@example.com">

# Failure case
result = CreateUser.call(login: "invalid")
result.failure?   # => true
result.errors     # => { password: ["is required"] }

Installation

Add this line to your application's Gemfile:

gem 'domainic-command'

Or install it yourself as:

gem install domainic-command

Key Features

• Type-Safe Arguments: Define and validate input parameters with clear type constraints
• Explicit Outputs: Specify expected return values and their requirements
• Standardized Error Handling: Consistent error reporting with detailed failure information
• Thread Safety: Built-in thread safety for class definition and execution
• Command Composition: Build complex workflows by combining simpler commands
• Self-Documenting: Generate clear documentation from your command definitions
• Framework Agnostic: Use with any Ruby application (Rails, Sinatra, pure Ruby)

Documentation

For detailed usage instructions and examples, see USAGE.md.

Contributing

We welcome contributions! Please see our Contributing Guidelines for:

• Development setup and workflow
• Code style and documentation standards
• Testing requirements
• Pull request process

Before contributing, please review our Code of Conduct.

License

The gem is available as open source under the terms of the MIT License.