EMRPC is a EventMachine-based remote procedure call library. It looks like DRb, but is much more efficient and provides asynchronous erlang-like interface along with blocking synchronous interface.

Author: Oleg Andreev <oleganza@gmail.com>

FEATURES

1. Object-oriented evented API based on lightweight processes called Pids.

2. Automatically reconnecting clients (blocking and evented).

3. Support for both TCP and Unix sockets. (Use “emrpc://host:port” or “unix:///path/to/my.sock”)

4. Modularity and good specs coverage: EMRPC is easy to learn, extend and optimize.

VERSION AND STATUS

This is v0.3 alpha. It is being used in several projects of my own, but is not tested on many interesting cases. It has also several issues with performance and specs stability (see TODO file).

THANKS TO

• linkfeed.ru for the real-world EMRPC-based application.

• pierlis.com for the table/chair/wifi in Paris.

EXAMPLES

You may try out examples using bin/emrpc IRB session. Just open the console and paste the code.

---

HELLO WORLD (BLOCKING API)

class HelloWorld
  def action
    "Hello!"
  end
end

server = EMRPC::Server.new(:address => 'emrpc://localhost:4000/', 
                           :backend => HelloWorld.new)
EM::safe_run(:background) { }

server.start

client = EMRPC::Client.new('emrpc://localhost:4000/')
client.action == "Hello!" #=> true

---

HELLO WORLD (EVENTED API)

class HelloWorld
  include Pid
  def action(sender)
    puts "HelloWorld replies to the sender #{sender}..."
    sender.reply(self, "Hello!")
  end
end

class User
  include Pid
  def connected(pid)
    puts "Pid #{pid} connected with the user."
    pid.action(self)
  end
  def reply(pid, msg)
    puts "Pid #{pid} replied: #{msg}"
  end
end

EM::run do
  hw = HelloWorld.new
  hw.bind('emrpc://localhost:4000/')  # bind a pid to the address 

  oleg = User.new
  oleg.connect('emrpc://localhost:4000/') # connect to that address
end

# Output:
Pid #<EMRPC::RemotePid:0x143b740> connected with the user.
HelloWorld replies to the sender #<User:0x143b4d4>...
Pid #<HelloWorld:0x143d540> replied: Hello!

---

HELLO WORLD (EVENTED WRAPPER, MIXED API)

# in first process:
class HelloWorld
  def action
    "Hello!"
  end
end

server = EMRPC::Server.new(:address => 'emrpc://localhost:4000/', 
                           :backend => HelloWorld.new)

EM::run do
  server.start
end

# in the other process (actually, this works in the same process with the server too):
class User
  include Pid
  def connected(pid)
    puts "Pid #{pid} connected to the user."
    pid.send(self, :action)
  end
  def on_return(pid, msg)
    puts "Pid #{pid} replied: #{msg}"
  end
end

EM::run do
  oleg = User.new
  oleg.connect('emrpc://localhost:4000/') # connect to that address
end

# Output:
Pid #<EMRPC::RemotePid:0x143b740> connected to the user.
Pid #<HelloWorld:0x143d540> replied: Hello!

---