验证 Akka Persistence 命令的最佳实践

Question

假设我们有一个命令 AddUser:

case class AddUser(username: String, password: String)

在持久化事件之前验证此命令的最佳方法是什么？比如这样搞，好像有点乱。

override def receiveCommand: Receive = {
    case AddUser(username, password) =>
      if (username.trim.length > 25) {
        sender() ! UsernameTooLong
      } else if (password.trim.length > 25) {
        sender() ! PasswordTooLong
      } else {
        persist(UserAdded(User(username, password))) {
          userAdded =>
            sender() ! userAdded
        }
      }
}

Answer 1

您需要使用接收管道模式：http://doc.akka.io/docs/akka/2.4.1/contrib/receive-pipeline.html

你可以这样做：

trait AuthenticatedUser { this: ReceivePipeline =>
   pipelineInner {
    case msg@AddUser(username, password) => 
     if (username.trim.length > 25) {
        sender() ! UsernameTooLong
     } else if (password.trim.length > 25) {
        sender() ! PasswordTooLong
     } else {
       Inner(msg)
     }
   case msg => Inner(msg)
   }
}

class UserActor extends Actor with ReceivePipeline with AuthenticatedUser {

 def receive = {
   case AddUser(username, password) =>
    persist(UserAdded(User(username, password))) {
          userAdded =>
            sender() ! userAdded
        }
  }
}

PS: 我没有编译和测试这段代码，但我相信它会起作用，如果有任何问题请告诉我。

验证 Akka Persistence 命令的最佳实践

Best practice to validate Akka Persistence commands

scala

akka

akka-persistence