Class: NexusCqrs::CommandExecutor

Inherits:
Object
  • Object
show all
Defined in:
lib/nexus_cqrs/command_executor.rb

Instance Method Summary collapse

Constructor Details

#initialize(command_bus) ⇒ CommandExecutor

Returns a new instance of CommandExecutor.

Parameters:



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# File 'lib/nexus_cqrs/command_executor.rb', line 6

def initialize(command_bus)
  @bus = command_bus
  @logger = logger
end

Instance Method Details

#autoregister(base_class, dir = 'app/domain/commands', ignore_strings = ['.rb', 'app/domain/']) ⇒ Object 



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# File 'lib/nexus_cqrs/command_executor.rb', line 16

def autoregister(base_class, dir = 'app/domain/commands', ignore_strings = ['.rb', 'app/domain/'])
  if defined?(Rails)
    # Iterate over the directory passed and find all ruby files.
    Dir["#{dir}/**/*.rb"].each do |file|
      # Constantize class name to constant to force rails to autoload this class.
      # Note that autoloading won't work when testing this gem standalone, but this does trigger the necessary
      # loading when in a rails environment.
      ignore_strings.each do |i|
        file.slice!(i)
      end
      @logger.debug { "Attempting constantize of #{file}" }
      file.camelize.constantize
    rescue NameError => e
      @logger.warn { "Failed autoregister #{file.camelize}, received NameError: #{e}" }
    end
  end

  ObjectSpace.each_object(Class).select { |klass| klass < base_class }.each do |c|
    @logger.debug { "Attempting auto registration of #{c}" }
    handler_name = (c.to_s + "Handler")
    begin
      handler = handler_name.constantize.new
    rescue NameError
      @logger.warn { "Command `#{c}` tried to autoregister `#{handler_name}` but the class was not found" }
      next
    end

    if handler.respond_to?(:call)
      register_command(c, handler)
    else
      @logger.warn { "Command `#{c}` tried to autoregister `#{handler_name}` but `call` method did not exist" }
    end
  end
end

#command_bus ⇒ NexusCqrs::CommandBus

Returns the bus used by this executor

Returns:



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# File 'lib/nexus_cqrs/command_executor.rb', line 54

def command_bus
  @bus
end

#configure_handlers(&block) ⇒ Object

Configuration method for allowing handlers to be registered in bulk

Examples:

Registering all queries

executor.configure_handlers do |executor|
  executor.autoregister(NexusCqrs::BaseQuery, 'app/domain/queries')
end

Registering a query manually

executor.configure_handlers do |executor|
  executor.register_command(NexusCqrs::BaseQuery, NexusCqrs::BaseQueryHandler)
end

Parameters:

  • block (Proc) —

    Block to execute to register handlers

See Also:



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# File 'lib/nexus_cqrs/command_executor.rb', line 95

def configure_handlers(&block)
  @register_handlers = block
  @register_handlers.call(self)
end

#execute(message) ⇒ Object

Executes a specific handler on the bus, passing in the provided message (Query/Command)

Parameters:



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# File 'lib/nexus_cqrs/command_executor.rb', line 61

def execute(message)
  @bus.call(message)
end

#logger ⇒ Object

Get logger instance depending on runtime environment.



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# File 'lib/nexus_cqrs/command_executor.rb', line 12

def logger
  defined?(Rails) && defined?(Rails.logger) ? Rails.logger : Logger.new(STDOUT)
end

#register_command(message, handler) ⇒ Object

Helper method for registering a handler on the bus

Parameters:

See Also:



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# File 'lib/nexus_cqrs/command_executor.rb', line 70

def register_command(message, handler)
  @bus.register(message, handler)
end

#reregister_handlers ⇒ Object

Clears all handlers from the bus and invokes the block passed to ‘configure_handlers` to re-register all the handlers again. This can be useful in tests - as we don’t want state to persist across handlers



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# File 'lib/nexus_cqrs/command_executor.rb', line 76

def reregister_handlers
  return if @register_handlers.nil?

  @bus.clear_handlers
  @register_handlers.call(self)
end