Interface segregation principle

isp.rb

module ClientFeatures
  def authenticate(username, password)
    puts "Authenticating #{username}..."
  end

  def send_notification(message)
    puts "Sending notification: #{message}"
  end

  def send_email(to, subject, body)
    puts "Sending email to #{to}: #{subject}"
  end

  def log_request(endpoint)
    puts "Logging request to #{endpoint}"
  end

  def track_analytics(event)
    puts "Tracking analytics: #{event}"
  end
end

# Base class with full CRUD operations
class BaseClient
  def create(data)
    puts "Creating resource: #{data}"
  end

  def read(id)
    puts "Reading resource: #{id}"
  end

  def update(id, data)
    puts "Updating resource #{id}: #{data}"
  end

  def delete(id)
    puts "Deleting resource: #{id}"
  end

  def batch_operation(items)
    puts "Performing batch operation on #{items.length} items"
  end
end

class ReadOnlyClient < BaseClient
  include ClientFeatures

  def initialize(name)
    @name = name
  end

  def fetch(id)
    # Only uses read() from BaseClient
    read(id)

    # Only uses log_request() from ClientFeatures
    log_request("/api/resources/#{id}")
  end
end

# Demonstration
client = ReadOnlyClient.new("read-only-api")

# What the client actually uses:
client.fetch(123)