CODEWITHSUNDEEP
javaplayframeworkjava-8
ss1
ss1

Reputation: 1191

PlayWS - How to throw an exception when Request Timeout is reached?

When performing long downloads with PlayWS, which uses CompletableFuture, these sometimes reach the defined request timeout. When that happens, then PlayWS doesn't seem to throw an exception (at least in my configuration), so the download can't be marked as failed and is processed although the data is corrupt.

Please excuse this abomination of code: 

final CompletionStage<WSResponse> futureResponse = this.playWS.client
        .url(importSource.getDownloadUrl())
        .setMethod(HttpMethod.GET)
        .setRequestTimeout(Duration.ofSeconds(5)) // When the timeout is reached, the download gets canceled
        .stream();

try {
    futureResponse
            .thenAccept(res -> {
                try (OutputStream outputStream = Files.newOutputStream(file.toPath())) {
                    final Source<ByteString, ?> responseBody = res.getBodyAsSource();
                    final Sink<ByteString, CompletionStage<Done>> outputWriter =
                            Sink.foreach(bytes -> {
                                outputStream.write(bytes.toArray());
                            });
                    responseBody
                            .runWith(outputWriter, this.playWS.materializer)
                            .whenComplete((value, error) -> {
                                System.out.println("VALUE: "+value); // == "Done"
                                System.out.println("Error: "+error); // == null
                            })
                            .exceptionally(exception -> {
                                throw new IllegalStateException("Download failed for: " + importSource.getDownloadUrl(), exception);
                            })
                            .toCompletableFuture().join();
                } catch (final IOException e) {
                    throw new IllegalStateException("Couldn't open or write to OutputStream.", e);
                }
            })
            .exceptionally(exception -> {
                throw new IllegalStateException("Download failed for: " + importSource.getDownloadUrl(), exception);
            })
            .toCompletableFuture().get();
} catch (InterruptedException | ExecutionException e) {
    throw new IllegalStateException("Couldn't complete CompletableFuture.", e);
}

Am I doing something fundamentally wrong or is this a bug?

The only solutions I see are:

  1. Count the received bytes and compare them to the Content-Length header.
  2. Set the request timeout to -1 (indefinite).

Thanks for any suggestion.

Upvotes: 0

Views: 173

Answers (1)

Daniel Hinojosa
Daniel Hinojosa

Reputation: 992

I think there is some over-complication.

You can just attach from the Future or CompletableStage to Source. Akka Streams has a more robust API than CompletableFuture (my opinion)

final CompletionStage<WSResponse> futureResponse = this.playWS.client
        .url(importSource.getDownloadUrl())
        .setMethod(HttpMethod.GET)
        .setRequestTimeout(Duration.ofSeconds(5)) 
        .stream();

Source<WSResponse> source = Source.fromCompletableStage(futureResponse);
source.map(...).filter(...).recover(...).runforeach(..., playWS.materializer)

Upvotes: 1

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