Overriding invoke_method example

calculator.rb

class Calculator < MyHandler
  before_method_invokation :log_method_call

  expose_all

  def add(left, right)
    left + right
  end
  
  private
  
  def log_method_call
    puts "Received Calculator##{json_rpc_request.method} with params: #{json_rpc_request.params}"
  end
end

handler.rb

require 'active_support'

class MyHandler
  include ActiveSupport::Callbacks
  include JsonRpc::Handler

  define_callbacks :method_invokation

  class << self
    [:before, :around, :after].each do |kind|
      define_method "#{kind}_method_invokation" do |*method_names|
        options = method_names.extract_options!
        _normalize_callback_options(options)

        method_names.each do |method_name|
          set_callback :method_invokation, kind, method_name, options
        end
      end
    end

    private

    def _normalize_callback_options(options)
      _normalize_callback_option(options, :only, :if)
      _normalize_callback_option(options, :except, :unless)
    end

    def _normalize_callback_option(options, from, to)
      if from = options[from]
        from = Array(from).map { |o| "json_rpc_request.method.split('.').last == '#{o}'" }.join(' || ')
        options[to] = Array(options[to]).unshift(from)
      end
    end
  end

  def invoke_method(method_name, params)
    run_callbacks(:method_invokation) do
      super
    end
  end
end