require 'protobuf/logger'

module Protobuf
  module Rpc
    class ServiceDispatcher
      include ::Protobuf::Logger::LogMethods

      attr_reader :env

      def initialize(app)
        # End of the line...
      end

      def call(env)
        @env = env

        env.response = dispatch_rpc_request
        env
      end

      def rpc_service
        @rpc_service ||= env.rpc_service.new(env)
      end

    private

      # Call the given service method.
      def dispatch_rpc_request
        unless rpc_service.respond_to?(method_name)
          raise MethodNotFound.new("#{service_name}##{method_name} is not a publicly defined method.")
        end

        rpc_service.callable_rpc_method(method_name).call
        rpc_service.response
      end

      def method_name
        env.method_name
      end

      def service_name
        env.service_name
      end
    end
  end
end

require 'protobuf/logger'

module Protobuf
  module Rpc
    class ServiceDispatcher
      include ::Protobuf::Logger::LogMethods

      attr_reader :env

      def initialize(app)
        # End of the line...
      end

      def call(env)
        @env = env

        env.response = dispatch_rpc_request
        env
      end

      def rpc_service
        @rpc_service ||= env.rpc_service.new(env)
      end

    private

      # Call the given service method.
      def dispatch_rpc_request
        rpc_service.callable_rpc_method(method_name).call
        rpc_service.response
      rescue NoMethodError => e
        if e.message =~ /#{method_name}/
          raise MethodNotFound.new("#{service_name}##{method_name} is not implemented.")
        end

        raise
      end

      def method_name
        env.method_name
      end

      def service_name
        env.service_name
      end
    end
  end
end

--- 
+++ 
@@ -26,14 +26,12 @@
 
       # Call the given service method.
       def dispatch_rpc_request
+        unless rpc_service.respond_to?(method_name)
+          raise MethodNotFound.new("#{service_name}##{method_name} is not a publicly defined method.")
+        end
+
         rpc_service.callable_rpc_method(method_name).call
         rpc_service.response
-      rescue NoMethodError => e
-        if e.message =~ /#{method_name}/
-          raise MethodNotFound.new("#{service_name}##{method_name} is not implemented.")
-        end
-
-        raise
       end
 
       def method_name
Check if the service responds to the given method

Instead of catching all NoMethodErrors and checking the message for the
method name (which is brittle), simply check to see if the service
responds to the method. If it's not a publicly defined instance method,
raise an RPC MethodNotFound error.
