how is (myActor ? q) async in following scalatra example?

StackOverflow https://stackoverflow.com/questions/19428289

Question

in this post Angular.js with Scalatra it is said that the http call is asynchronous. I see that the call to the actor is done with:

myActor ? q

however in scalatra home page i see they encapsulate the call with AsyncResult see:

get("/"){
    new AsyncResult { def is = 
      Future {
        // Add async logic here
        <html><body>Hello Akka</body></html>
      }
    }
  }

is there a difference between the two? I understand that the first one is calling an actor which returns a future, does that mean that both calls are async?

can you elaborate a little more about how the synchronicity of 

 get("/query/:key/:value") {
    contentType = formats("json")
    val q = Query(params("key"), params("value"), mongoColl)
    myActor ? q
  }

is the http thread released?

Was it helpful?

Solution

Both calls are async. 'get' will either return a result or timeout. The request will wait for some kind of reaction from the Actor in this case however.

The application will not lock up if a result is not returned because of the protected implicit val timeout = Timeout(10) at the top of the class (this will instruct myActor ? q to give up on a result after 10 seconds).

The second example is a pure future based approach in which the body of 'Future' performs a series of operations async and onComplete returns a result.

I suggest you read Akka Actors documentation for more details

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