Unable to Materialise Request Body in Action Filter

Play Framework
1

Please refer to this SO post which describes the problem and this GitHub post on latest conversation on this issue with the Playframework developers

2

Hmm… I guess you can use

request.body.asInstanceOf[Request[AnyContent]].body.asFormUrlEncoded

(you need to import play.api.mvc.AnyContent)

Seems like the Request[A] passed is still too generic and casting should help. Of course only when the body parser you use gives you AnyContent, but that is the default anyway.

3

This was one of the first solutions I tried but it doesn’t work as well. I always get back a AnyContentEmpty result.

4

Actually, this results in an exception:

play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[ClassCastException: play.api.mvc.AnyContentAsFormUrlEncoded cannot be cast to play.api.mvc.Request]]
at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:351)
at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:267)
at play.core.server.AkkaHttpServer$$anonfun$1.applyOrElse(AkkaHttpServer.scala:448)
at play.core.server.AkkaHttpServer$$anonfun$1.applyOrElse(AkkaHttpServer.scala:446)
at scala.concurrent.Future.$anonfun$recoverWith$1(Future.scala:417)
at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:41)
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:92)

5

I actually think this is a bug which is why I opened the issue in GitHub.

Even though the Content-Length indicates there is content in the request body, that request body cannot be accessed in any shape or form inside the filter method of the Action Filter. I also conjecture it is the same for all the other types of Action composition types.

6

Sorry, actually I meant:

request.asInstanceOf[Request[AnyContent]].body.asFormUrlEncoded

Please try this.

1 Like
7

Yes, this works! From what I remember last time, I was trying to cast directly to AnyContentAsFormUrlEncoded and I kept getting back AnyContentAsEmpty.

Even though this does work and unblocks me, is there a better solution than casting?

8

Doesn’t looks like there is a better solution. However I primarily use the Java API myself, so maybe I am wrong. Maybe someone else will comes up with a better solution.

9

Any idea why my attempt does not work?

  override protected def filter[A](request: Request[A]): Future[Option[Result]] =
    parse.formUrlEncoded.apply(request).run().map {
      case Left(result) => Some(result)
      case Right(formUrl) =>
        logger.info(formUrl.isEmpty.toString)
        None
    }
}
10

It depends on which body parser the action is using, but usually, you are either using the default one (which produces a body of type play.api.mvc.AnyContent) or something more specific, for example, play.api.mvc.AnyContentAsFormUrlEncoded. I assume your action is NOT using play.api.mvc.PlayBodyParsers.formUrlEncoded since the cast failed before. The docs have more information about it, but you need to do:

// This is your action
def action = Action(parse.tolerantFormUrlEncoded) { req: Request[Map[String, Seq[String]]] =>
  Ok(s"Request body: ${req.body}")
}

And ActionFilter can look like this:

class SomeActionFilter @Inject()(implicit val executionContext: ExecutionContext) extends ActionFilter[Request] {
  override protected def filter[A](request: Request[A]): Future[Option[Result]] = Future.successful {
    request.body match {
      case AnyContentAsFormUrlEncoded(data) =>
        println(s"Checking request data: $data")
        // Suppose checking data failed, so return a BadRequest
        Some(Results.BadRequest)
      case _ =>
        // Decide what to do if it is not the expected body type
        None
    }
  }
}

Best.

1 Like
11

Thanks @marcospereira.

You’re right, in my main Action I was not using any body parser. I was simply composing the action as follows:

Action.andThen(exampleFilter)

I still can’t it to work with your new proposed solution, see here:

import javax.inject.Inject
import play.api.Logging
import play.api.mvc._

import scala.concurrent.{ExecutionContext, Future}

class ExampleActionFilter @Inject()(
  implicit val executionContext: ExecutionContext
) extends ActionFilter[Request]
    with Logging {
  override protected def filter[A](request: Request[A]): Future[Option[Result]] = Future.successful {
    request.body match {
      case AnyContentAsFormUrlEncoded(data) =>
        logger.info(s"Checking request data: $data")
        // Suppose checking data failed, so return a BadRequest
        Some(Results.BadRequest)
      case _ =>
        logger.info(s"No data")
        // Decide what to do if it is not the expected body type
        None
    }
  }
}

With a controller method which looks like this:

  def status = Action(parse.tolerantFormUrlEncoded).andThen(exampleActionFilter) {
    req: Request[Map[String, Seq[String]]] =>
      Ok(s"Request body: ${req.body}")
  }

This does print out:

Request body: ListMap(param1 -> List(value1), param2 -> List(value2))

But it does not print out “Checking request data: …” because it doesn’t match on AnyContentAsFormUrlEncoded.