Remote Procedure Call Server and Client for Crystal
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Latest commit 8b116a1 Dec 6, 2018

README.md

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::SocketServer.new("127.0.0.1", 9000).run
end

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

p result.error # => SimpleRpc::Error::OK
p result.value # => 16.5

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

p result.error # => SimpleRpc::Error::OK
p result.value # => 16.5

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

require "simple_rpc"

record Struct1, x : String, y : Hash(String, String) { include MessagePack::Serializable }
record Struct2, q : Float64, w : Array(Tuple(Int32, String)) { include MessagePack::Serializable }

class MyRpc 
  include SimpleRpc::Proto

  def complex(data : Struct1) : Struct2
    # ...
  end
end

Example calling from ruby

# 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