This extension enables to use block on messagepack-prc. Free variable must be an object which acccepts 'Marshal.dump'.

use_closure_on_msgpack_rpc.rb

require 'msgpack/rpc'
require 'sourcify'

# client extension
module ClientProcHandler
  def call_block(&proc)
    self.call(:process_block,proc_dump(proc))
  end
  private
  def proc_dump(proc)
    local_variables = eval('local_variables',proc.binding).inject(Hash.new){|h,i|
      s = Marshal.dump(eval(i.to_s,proc.binding)) rescue (next h)
      h[i]= s
      h
    }
    return proc.to_source,local_variables
  end
end

# server extension
class ServerProcHandler
  def process_block(dumped)
    p = proc_load(*dumped)
    return p.call
  end

  private

  def proc_load(stmt, local_variables_dump)
    local_variables = local_variables_dump.each_with_object(Hash.new){|(i,v),obj| obj[i.to_sym]=Marshal.load(v)}
    prog = String.new
    prog << local_variables.map{|i,v| "#{i}=local_variables[:#{i}]"}.join("\n")+"\n"
    prog << stmt
    puts prog
    eval(prog)
  end
end


# how to use

use_case = 1
is_server = ARGV[0] == 'server'

if is_server
  # server code
  server = MessagePack::RPC::Server.new
  server.listen('0.0.0.0', 18800, ServerProcHandler.new)
  server.run
else
  # client code
  case use_case
  when 1 then
    client = MessagePack::RPC::Client.new('localhost', 18800).extend(ClientProcHandler)
    j = 22
    result = client.call_block do
      j*100
    end
    puts result # (stdout) => 2200
    
  when 2 then 
    require 'td-client'
    require 'mongo'
    client = MessagePack::RPC::Client.new('localhost', 18800).extend(ClientProcHandler)
    job = TreasureData::Client.new(API_KEY).query('database','some_hive_query')
    date = Date.today
    client.call_block do
      job.wait
      # store to database
      collection = MONGODB.collection('some_collection')
      job.result.each do |result|
        collection.insert(score: result, date: date)
      end
    end
  end
end