[akka-user] Re: Materialize future after content negotiation
Today if found out that content negotiation is not done in
Marshal(result).to[__] case. (I should had tests for that)
Only solution I can find is to copy Marshal.toResponseFor method as it is
not expandable at all. and add flatMap(identity) there:
implicit def toFutureResponseMarshallable[A](_value: A)(implicit
_marshaller: FutureResponseMarshaller[A]): ToResponseMarshallable = new
ToResponseMarshallable{
type T = A
def value: T = _value
implicit def marshaller: ToResponseMarshaller[A] = null
override def apply(request: HttpRequest)(implicit ec: ExecutionContext):
Future[HttpResponse] = {
import akka.http.scaladsl.util.FastFuture._
import akka.http.scaladsl.marshalling.Marshal._
val ctn = ContentNegotiator(request.headers)
_marshaller(value).fast.map { marshallings ⇒
val supportedAlternatives: List[ContentNegotiator.Alternative] =
marshallings.collect {
case Marshalling.WithFixedContentType(ct, _) ⇒ ContentNegotiator
.Alternative(ct)
case Marshalling.WithOpenCharset(mt, _) ⇒ ContentNegotiator
.Alternative(mt)
}(collection.breakOut)
val bestMarshal = {
if (supportedAlternatives.nonEmpty) {
ctn.pickContentType(supportedAlternatives).flatMap {
case best @ (_: ContentType.Binary | _: ContentType.
WithFixedCharset | _: ContentType.WithMissingCharset) ⇒
marshallings collectFirst { case Marshalling.
WithFixedContentType(`best`, marshal) ⇒ marshal }
case best @ ContentType.WithCharset(bestMT, bestCS) ⇒
marshallings collectFirst {
case Marshalling.WithFixedContentType(`best`, marshal) ⇒
marshal
case Marshalling.WithOpenCharset(`bestMT`, marshal)⇒
() ⇒ marshal(bestCS)
}
}
} else None
} orElse {
marshallings collectFirst { case Marshalling.Opaque(marshal) ⇒
marshal }
} getOrElse {
throw UnacceptableResponseContentTypeException(
supportedAlternatives.toSet)
}
bestMarshal()
*}.flatMap(identity)*
}
}
On Wednesday, September 27, 2017 at 12:34:11 PM UTC+3, Muntis Grube wrote:
>
> Thanks. It seams that it worked:
>
> type FutureResponse = Future[HttpResponse]
> type FutureResponseMarshaller[T] = Marshaller[T, FutureResponse]
>
> def httpResponse(iterator: Iterator[Data])(implicit ec: ExecutionContext
> ) = {
> Source.fromGraph(sourceGrap(iterator)).runWith(entitySink).map(entity
> => HttpResponse(entity = entity))
> }
>
> val toResponseIteratorJsonMarshaller: FutureResponseMarshaller[Iterator[
> Data]] =
> Marshaller.withFixedContentType(`application/json`) {
> result => httpResponse(result)
> }
>
> implicit val toResponseIteratorMarshaller: FutureResponseMarshaller[
> Iterator[Data]] =
> Marshaller.oneOf(
> toResponseIteratorJsonMarshaller,
> toResponseIteratorOdsMarshaller,
> toResponseIteratorExcelMarshaller
> )
>
>complete {
> val result = ???
> Marshal(result).to[FutureResponse].flatMap(identity)
>}
>
>
>
>
> On Tuesday, September 26, 2017 at 4:13:15 PM UTC+3,
> johannes...@lightbend.com wrote:
>>
>> Oops, one should read the whole question before answering... Just saw
>> that you already tried that. Unfortunately, it seems that this is indeed a
>> shortcoming of the current model.
>>
>> I guess with a bit of fiddling you could try making all of those
>> marshallers marshal to `Future[HttpResponse]` instead of `HttpResponse` and
>> then use something like
>>
>>
>>
>> val toResponseIteratorJsonMarshaller: Marshaller[Iterator[Data],
>> Future[HttpResponse]] =
>> Marshaller.withFixedContentType(`application/json`) {
>> result => httpResponse(result)
>> }
>>
>> implicit val toResponseIteratorMarshaller: Marshaller[Iterator[Data],
>> Future[HttpResponse]] =
>> Marshaller.oneOf(
>> toResponseIteratorJsonMarshaller,
>> toResponseIteratorOdsMarshaller,
>> toResponseIteratorExcelMarshaller
>> )
>>
>> and then in your route:
>>
>> val responseFuture =
>> Marshal(data).toResponseFor(request)(toResponseIteratorMarshaller): //
>> Future[Future[HttpResponse]]
>>
>> .flatMap(identity)
>> complete(responseFuture)
>>
>> Would be interesting to know if that works.
>>
>> Johannes
>>
>
--
>> 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
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For more
[akka-user] Re: Materialize future after content negotiation
Thanks. It seams that it worked:
type FutureResponse = Future[HttpResponse]
type FutureResponseMarshaller[T] = Marshaller[T, FutureResponse]
def httpResponse(iterator: Iterator[Data])(implicit ec: ExecutionContext)
= {
Source.fromGraph(sourceGrap(iterator)).runWith(entitySink).map(entity =>
HttpResponse(entity = entity))
}
val toResponseIteratorJsonMarshaller: FutureResponseMarshaller[Iterator[
Data]] =
Marshaller.withFixedContentType(`application/json`) {
result => httpResponse(result)
}
implicit val toResponseIteratorMarshaller: FutureResponseMarshaller[
Iterator[Data]] =
Marshaller.oneOf(
toResponseIteratorJsonMarshaller,
toResponseIteratorOdsMarshaller,
toResponseIteratorExcelMarshaller
)
complete {
val result = ???
Marshal(result).to[FutureResponse].flatMap(identity)
}
On Tuesday, September 26, 2017 at 4:13:15 PM UTC+3,
johannes...@lightbend.com wrote:
>
> Oops, one should read the whole question before answering... Just saw that
> you already tried that. Unfortunately, it seems that this is indeed a
> shortcoming of the current model.
>
> I guess with a bit of fiddling you could try making all of those
> marshallers marshal to `Future[HttpResponse]` instead of `HttpResponse` and
> then use something like
>
>
>
> val toResponseIteratorJsonMarshaller: Marshaller[Iterator[Data],
> Future[HttpResponse]] =
> Marshaller.withFixedContentType(`application/json`) {
> result => httpResponse(result)
> }
>
> implicit val toResponseIteratorMarshaller: Marshaller[Iterator[Data],
> Future[HttpResponse]] =
> Marshaller.oneOf(
> toResponseIteratorJsonMarshaller,
> toResponseIteratorOdsMarshaller,
> toResponseIteratorExcelMarshaller
> )
>
> and then in your route:
>
> val responseFuture =
> Marshal(data).toResponseFor(request)(toResponseIteratorMarshaller): //
> Future[Future[HttpResponse]]
>
> .flatMap(identity)
> complete(responseFuture)
>
> Would be interesting to know if that works.
>
> Johannes
>
--
>> 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
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[akka-user] Re: Materialize future after content negotiation
Oops, one should read the whole question before answering... Just saw that
you already tried that. Unfortunately, it seems that this is indeed a
shortcoming of the current model.
I guess with a bit of fiddling you could try making all of those
marshallers marshal to `Future[HttpResponse]` instead of `HttpResponse` and
then use something like
val toResponseIteratorJsonMarshaller: Marshaller[Iterator[Data],
Future[HttpResponse]] =
Marshaller.withFixedContentType(`application/json`) {
result => httpResponse(result)
}
implicit val toResponseIteratorMarshaller: Marshaller[Iterator[Data],
Future[HttpResponse]] =
Marshaller.oneOf(
toResponseIteratorJsonMarshaller,
toResponseIteratorOdsMarshaller,
toResponseIteratorExcelMarshaller
)
and then in your route:
val responseFuture =
Marshal(data).toResponseFor(request)(toResponseIteratorMarshaller): //
Future[Future[HttpResponse]]
.flatMap(identity)
complete(responseFuture)
Would be interesting to know if that works.
Johannes
--
>> 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
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[akka-user] Re: Materialize future after content negotiation
Hi Mantis,
you are right, `Marshaller.withFixedContentType` is a bit restricted in
that regard. Fortunately, it is only a shortcut for simpler cases and the
full asynchronous functionality is available for marshallers. Try something
like
Marshaller[Iterator[Data], HttpResponse] { implicit ec => it =>
doSomethingWhichReturnsFutureOfHttpResponse.map { response =>
Marshalling.WithFixedContentType(contentType, () ⇒ response) :: Nil
}
}
Cheers,
Johannes
On Wednesday, September 20, 2017 at 12:10:24 PM UTC+2, Muntis Grube wrote:
>
> Hello
>
> Is there way to trick marshallers to accept my Future[HttpResponse]
> in withFixedContentType ?
>
> To provide large responses from cursor I'm trying to materialize class
> that extends Iterator. To do that we created SourceShape[ByteString] that
> wraps the iterator and
> corrseponding GraphStageWithMaterializedValue[SinkShape[ByteString],
> Future[MessageEntity]]
> that pools first values from source and decides if HttpEntity.Strict
> or HttpEntity.Chunked should be creaded.
>
>
> def httpResponse(iterator: Iterator[Data])(implicit ec: ExecutionContext
> ) = {
> Await.result(Source.fromGraph(sourceGrap(iterator)).runWith(entitySink
> ).map(entity => HttpResponse(entity = entity)), 60 seconds)
> }
>
> val toResponseIteratorJsonMarshaller: ToResponseMarshaller[Iterator[Data
> ]] =
> Marshaller.withFixedContentType(`application/json`) {
> result => httpResponse(result)
> }
>
> implicit val toResponseIteratorMarshaller: ToResponseMarshaller[Iterator
> [Data]] =
> Marshaller.oneOf(
> toResponseIteratorJsonMarshaller,
> toResponseIteratorOdsMarshaller,
> toResponseIteratorExcelMarshaller
> )
>
>
> As you can probably guess the biggest concern for me is
> unnecessary Await.result. One of the promising solutions was to drop await
> and to rewrite marshaller as:
>
> def httpResponse(iterator: Iterator[Data])(implicit ec: ExecutionContext)
> = {
>Source.fromGraph(sourceGrap(iterator)).runWith(entitySink).map(entity
> => HttpResponse(entity = entity))
> }
>
> val toResponseIteratorJsonMarshaller: ToResponseMarshaller[Iterator[Data
> ]] = Marshaller{ implicit ec => result =>
>httpResponse(result).map(response => Marshalling.WithFixedContentType(
> `application/json`, () => response ) :: Nil)
> }
>
> Unfortunately project structure is built that way that query is executed
> and cursor is opened when iterator hasNext or next methods are called. And
> in this solution it is done before content negotiation is done and causes
> multiple queries called for each response type at best or multiple queries
> on one connection at worst.
>
>
> Thanks.
> Muntis
>
--
>> 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
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