Example pure Ruby client of the Arachni-RPC protocol

arachni_rpc_client_pure.rb

require 'socket'
require 'openssl'
require 'yaml'
require 'ap'

class Connection

    def initialize( opts )
        @opts = opts

        socket = TCPSocket.new( opts[:host], opts[:port] )

        @ssl_context = OpenSSL::SSL::SSLContext.new

        if opts[:ssl_cert] && opts[:ssl_pkey]
            @ssl_context.cert = OpenSSL::X509::Certificate.new( File.open( opts[:ssl_cert] ) )
            @ssl_context.key = OpenSSL::PKey::RSA.new( File.open( opts[:ssl_pkey] ) )
        end

        @ssl_socket = OpenSSL::SSL::SSLSocket.new( socket, @ssl_context )
        @ssl_socket.sync_close = true
        @ssl_socket.connect
    end

    def close
        @ssl_socket.close
    end

    def send_rcv_object( obj )
        send_object( obj )
        receive_object
    end

    def send_object( obj )
        serialized = serializer.dump( obj )
        @ssl_socket.puts( [ serialized.bytesize, serialized ].pack( 'Na*' ) )
    end

    def receive_object
        while data = @ssl_socket.gets
            (@buf ||= '') << data
            while @buf.size >= 4
                if @buf.size >= 4 + ( size = @buf.unpack( 'N' ).first )
                    @buf.slice!(0,4)

                    complete = @buf.slice!( 0, size )
                    @buf = ''
                    return serializer.load( complete )
                else
                    break
                end
            end
        end
    end

    private

    def serializer
        @opts[:serializer] ? @opts[:serializer] : YAML
    end


end

class Client

    def initialize( opts )
        @opts = opts
    end

    def call( msg, *args )
        conn = Connection.new( @opts )
        obj = conn.send_rcv_object( prep_request( msg, *args ) )['obj']
        conn.close

        handle_exception( obj )
        return obj
    end

    private

    def handle_exception( obj )
        if exception?( obj )
            e = RuntimeError.new( obj['exception'] )
            e.set_backtrace( obj['backtrace'] )
            raise e
        end
    end

    def exception?( obj )
        obj.is_a?( Hash ) && obj.include?( 'exception' )
    end

    def prep_request( msg, *args )
        {
            'message'     => msg, # RPC message in the form of 'handler.method'
            'args'        => args, # optional array of arguments for the remote method
            'token'       => @opts[:token], # optional authentication token,
        }
    end

end


client = Client.new(
    :host  => 'localhost',
    :port  => 7331,
    :token => 'superdupersecret'
)

begin
    ap client.call( 'bench.foo' )

    # Will throw exception because the remote method expects an argument
    #
    # ./examples/server.rb:15:in `foo': wrong number of arguments (0 for 1) (Exception)
        # from /home/zapotek/workspace/arachni-rpc/lib/arachni/rpc/server.rb:345:in `call'
        # from /home/zapotek/workspace/arachni-rpc/lib/arachni/rpc/server.rb:105:in `receive_request'
        # from /home/zapotek/workspace/arachni-rpc/lib/arachni/rpc/protocol.rb:66:in `receive_object'

rescue
end

# This is just an echo method so it will return: 2
ap client.call( 'bench.foo', 2 )