Support Alpakka listBucket

[jorkzijlstra]

Attempting a listBucket with alpakka results in Unsupported Content-Type, supported: application/xml; charset=UTF-8. This is likely caused by the returned content type from s3mock being plain/text for the InitiateMultiUpload request.

Using the latest master (containing the upload fix) lets me put the objects, but it does not let me do a listBucket after it.

It tries to Unmarshal:

HttpEntity.Strict(text/plain; charset=UTF-8,<ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
      <Name>testBucket</Name>
      None
      None
      
      <KeyCount>3</KeyCount>
      <MaxKeys>1000</MaxKeys>
      <IsTruncated>false</IsTruncated>
        <Contents>
          <Key>2b2ce68f-676a-4cab-9627-51d9e8408d46.xml</Key>
          <LastModified>2017-09-14T12:06:22Z</LastModified>
          <ETag>0</ETag>
          <Size>477332</Size>
          <StorageClass>STANDARD</StorageClass>
        </Contents>
    </ListBucketResult>)

So it seems to be a similar issue as in #61

The Output

Unsupported Content-Type, supported: application/xml; charset=UTF-8
akka.http.scaladsl.unmarshalling.Unmarshaller$UnsupportedContentTypeException: Unsupported Content-Type, supported: application/xml; charset=UTF-8
	at akka.http.scaladsl.unmarshalling.Unmarshaller$UnsupportedContentTypeException$.apply(Unmarshaller.scala:158)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$EnhancedFromEntityUnmarshaller$.$anonfun$forContentTypes$3(Unmarshaller.scala:114)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$$anon$1.apply(Unmarshaller.scala:58)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$EnhancedUnmarshaller$.$anonfun$mapWithInput$3(Unmarshaller.scala:91)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$$anon$1.apply(Unmarshaller.scala:58)
	at akka.http.scaladsl.unmarshalling.Unmarshaller.$anonfun$transform$3(Unmarshaller.scala:23)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$$anon$1.apply(Unmarshaller.scala:58)
	at akka.http.scaladsl.unmarshalling.Unmarshal.to(Unmarshal.scala:25)
	at akka.stream.alpakka.s3.impl.S3Stream.$anonfun$signAndGetAs$2(S3Stream.scala:248)
	at scala.concurrent.Future.$anonfun$flatMap$1(Future.scala:302)
	at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:37)
	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:60)
	at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
	at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:91)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:81)
	at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:91)
	at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:39)
	at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:415)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

[ncanibano]

We are testing s3 using alpakka with s3mock and we are also facing this same issue.