Support for classes and methods

[ream88]

In my current project I use a lot of DI in the form of:

def do_something(first: SomeClass, second: SomeClass.method(:some_method))
  # ...
end

Passing my dependencies to an ActiveJob fails with an ActiveJob::SerializationError: Unsupported argument type: Class (or respectively Unsupported argument type: Method). However, I think this could be easily done by serialising methods and classes into:

SomeClass.method(:some_method).to_global_id # => gid://App/SomeClass/some_method
SomeClass.to_global_id # => gid://App/SomeClass/class

Anyone interested in this feature? Suggestions?

[ream88]

Btw this could be more of an ActiveJob problem, just tell me if this belongs to the Rails repository.

[rafaelfranca]

I don't know if it is a good idea to include this behavior by default. Right now I think you can implement your own to_global_id implementation.

[kaspth]

Yeah, I don't see this in Global ID directly. I'd probably create some sort of wrapper model that takes a method or class and implements find. Good luck ❤️

[ream88]

Just for the record, and if anybody else needs something similar:
Solved it for now using this dirty (overwriting private methods 👎) module:

# class_and_method_arguments.rb
require 'active_job/arguments'


module ActiveJob
  module ClassAndMethodArguments
    def serialize_argument(argument)
      case argument
      when Class, Module
        URI::GID.build(app: GlobalID.app, model_name: argument.name, model_id: :itself).to_s
      when Method
        URI::GID.build(app: GlobalID.app, model_name: argument.receiver.name, model_id: argument.name).to_s
      else
        super
      end
    end


    def deserialize_argument(argument)
      case argument
      when String
        gid = URI::GID.parse(argument)

        # GID probably references an Model instance,
        # when model_id starts with numeric characters.
        case gid.model_id
        when /^\d+/
          super
        when 'itself'
          gid.model_name.constantize
        else
          gid.model_name.constantize.method(gid.model_id)
        end
      else
        super
      end
    rescue URI::BadURIError
      super
    end
  end


  Arguments.send :extend, ClassAndMethodArguments
end

# class_and_method_arguments_test.rb
require_relative '../../test_helper'


module ActiveJob
  class ClassAndMethodArgumentsTest < Minitest::Test
    def test_classes
      argument = [ActiveJob::Base]

      assert_equal argument, Arguments.deserialize(Arguments.serialize(argument))
    end


    def test_modules
      argument = [ActiveJob]

      assert_equal argument, Arguments.deserialize(Arguments.serialize(argument))
    end


    def test_methods
      argument = [ActiveJob::Base.method(:new)]

      assert_equal argument, Arguments.deserialize(Arguments.serialize(argument))
    end
  end
end