There was no intention in the tone, sorry if it came across that way. It just feels like there is an issue. I will check out the article, thanks.
On Monday, April 3, 2017 at 10:52:05 AM UTC-5, Ryan Tanner wrote: > > Leaving aside the tone of this post... > > Have you looked at the longer example of the DSL? > > > http://doc.akka.io/docs/akka-http/current/scala/http/routing-dsl/index.html#longer-example > > It has examples of how to delegate an endpoint's business logic off to > actors or futures. > > On Sunday, April 2, 2017 at 7:09:32 PM UTC-6, kraythe wrote: >> >> I was really excited about akka-http as I would be able to unburden my >> code from the baggage of play and handle my server side as a pure akka >> actors app but unless I am much mistaken something is dreadfully amiss with >> the implementation. >> >> One of the main core features is the actor paradigm and the integration >> of a rich actor system. However, the preferred approach to akka-http seems >> to be a throwback to one file programming. The main reason it seems this >> way is the DSL. Take this example from a tutorial: >> >> path("bank" / IntNumber) { id => >> get { >> complete { >> getById(id).map{result => >> if(result.isDefined) >> HttpResponse(entity =write(result.get)) >> else >> HttpResponse(entity ="This bank does not exist") >> } >> >> >> } >> } >> }~ >> path("bank" / "update") { >> post { >> entity(as[String]) { bankJson => >> complete { >> val bank =parse(bankJson).extract[Bank] >> update(bank).map{result => HttpResponse(entity ="Bank >> has been updated successfully")} >> } >> } >> } >> } >> } >> } >> >> >> Simple enough right? Too me I see the start of an anti-pattern but lets >> look further. It gets worse though, quickly, as shown in the akka-http >> documentation here >> <http://doc.akka.io/docs/akka-http/10.0.0/scala/http/routing-dsl/index.html#longer-example>. >> >> Still not bothered? The problem is that these examples are shallow and not >> rooted in the real world. In the bank application above would be hundreds >> of endpoints and each endpoint would have to validate data send by the >> user, check to see whether that data correct against the database and a >> dozen other things that would alter the nature of the return type to a bad >> request or internal error. The banking app would also have to log the >> problems so forensics can be done on malicious users. Just taking one route >> "deposit" would be several hundred lines of code INSIDE the route. However, >> it seems that there is no way to break off the route, offload it to another >> component (such as a Per Request Actor) and then continue the DSL where you >> left off. I had the chance to see for an app in another company that was >> asking my advice and their route is 12k lines long and at one point nested >> 30 levels deep. >> >> Now I know what you might say, "But Robert, you can break up the route >> into multiple files" which is true but something has to manually >> concatenate all of those routes together and they cant be done off of the >> main route. once you are in the routes DSL you are stuck there. Sure, you >> can call an actor with a future to do a completion but that actor itself >> might return data that requires a different kind of completion based upon >> certain criteria such as whether the user has had their account suspended. >> So if your completions are diverse, how do you break up the route? >> >> Now if someone has answers to these issues I would love to hear them but >> after researching I found that basically PRA's are deprecated in favor of a >> "convenient" DSL that entraps the user. For my purposes I opted to go with >> the low level API and factor off the route dispatching to a routing actor >> (yes, I know this is what the materializer does) and then just pull out >> route data the old fashioned way. My router, does path checking and then >> dispatches to another actor to handle that specific request and then sends >> the HttpResponse entity back to the sender which completes the ask and the >> route. My startup looks like this: >> >> val serverSource: Source[Http.IncomingConnection, Future[Http. >> ServerBinding]] = >> Http().bind(interface = "localhost", port = 8080) >> log.info("Server online at http://localhost:8080";) >> val bindingFuture: Future[Http.ServerBinding] = >> serverSource.to(Sink.foreach { connection => // foreach materializes >> the source >> import akka.pattern.ask >> println("Accepted new connection from " + connection.remoteAddress) >> connection.handleWithAsyncHandler(request => (httpRouter ? request >> ).mapTo[HttpResponse], parallelism = 4) >> }).run() >> >> >> A snippet of the router looks like this. >> >> class HttpRequestRouter extends Actor { >> protected val log = Logging(context.system, this) >> >> >> override def receive: Receive = { >> case request: HttpRequest => >> val requestId = UUID.randomUUID() >> request match { >> case HttpRequest(GET, Uri.Path("/"), _, _, _) => >> notFound(requestId, request) // todo Implement this >> case HttpRequest(POST, Uri.Path("/hello"), _, _, _) => >> invokeActor(classOf[HelloActor], requestId, request) >> case HttpRequest(GET, Uri.Path("/users"), _, _, _) => >> invokeActor(classOf[ListUsersActor], requestId, request) >> case HttpRequest(GET, Uri.Path("/addUser"), _, _, _) => >> invokeActor(classOf[AddUserActor], requestId, request) >> case uri => >> notFound(requestId, request) >> } >> case msg => log.warning("Received unknown message: {}", msg) >> } >> >> >> private def invokeActor(actorType: Class[_], requestId: UUID, request: >> HttpRequest) = { >> context.actorOf(Props(actorType, sender(), requestId, request), >> requestId.toString) >> }} >> >> This allows me to fork off PRAs as needed but it kind of stinks in one >> way because there are a lot of tools in the DSL for unpacking entities and >> so on that I cant use, or rather if there is a way I and neither I nor >> anyone within the reach of google has figured it out. >> >> So what am I missing? Do people really love this monstrous DSL even >> though in a 100 endpoint system the thing will be gargantuan? Is there a >> means to fork off at any point in the DSL and then "reboot the stream"? It >> would be nice if some of the DSL tools could be invoked arbitrarily inside >> the PRAs on the request object like. >> class OrderPRA(replyTo: ActorRef, requestId: UUID, request: HttpRequest) >> { >> >> // ... code >> sender.tell(withRequest(request) { >> entity(as[Order]) { order => >> complete { >> // ... write order to DB >> "Order received" >> } >> } >> }), self) >> } >> >> >> Opinions? Thoughts? >> >> >> >> >> -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. 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