simple_rpc

Remote Procedure Call Server and Client for Crystal. Designed to be reliable and stable (catch every possible protocall errors). Compatible with msgpack-rpc protocall.

Installation

Add this to your application's shard.yml:

dependencies:
  simple_rpc:
    github: kostya/simple_rpc

Usage

require "simple_rpc"

class MyRpc 
  include SimpleRpc::Proto

  def bla(x : Int32, y : String) : Float64
    x * y.to_f
  end
end

spawn do
  MyRpc::Server.new("127.0.0.1", 9000).run
end

sleep 0.1
client = MyRpc::Client.new("127.0.0.1", 9000)
result = client.bla(3, "5.5")

if result.ok?
  p result.value! + 1 # => 17.5
else
  p result.message!
end

When client code have no access to server proto, you can call raw requests:

require "simple_rpc"
class MyRpc 
  include SimpleRpc::Proto
end

client = MyRpc::Client.new("127.0.0.1", 9000)
result = client.request(Float64, :bla, 3, "5.5")

if result.ok?
  p result.value! # => 16.5
else
  p result.message!
end

If you want to exchange complex data types, you should include MessagePack::Serializable

require "simple_rpc"

class MyData
  include MessagePack::Serializable

  property a : Int32
  property b : String
  property c : Float64?
  property d : Hash(String, String)?

  @[MessagePack::Field(ignore: true)]
  property e : Int32
end

class MyRpc 
  include SimpleRpc::Proto

  def complex(value : Int32) : MyData
    # ...
  end
end

Example calling from ruby, with gem msgpack-rpc

require 'msgpack/rpc'

client = MessagePack::RPC::Client.new('127.0.0.1', 9000)
result = client.call(:bla, 3, "5.5")
p result # => 16.5