Custom Async Http Client Example for Java

[rameetchandok]

Hi team, i am working on integrating a custom http client implementation based on org.dispatchhttp.dispatch-core with S3AsyncClient however the REST request is sent via the client but there is response saying "400 Bad Request". Can you please help me understand the mistake and also provide an example in the documentation as well.

val builder = S3AsyncClient.builder .credentialsProvider( StaticCredentialsProvider.create( AwsBasicCredentials.create( s3Conf.key.accessKey, s3Conf.key.secretKey ) ) ) .serviceConfiguration(s3ConfigurationBuilder) .httpClient(httpClient)

Transformer

` implicit object AsyncExecuteRequestTransformer extends RequestTransformerFactory[AsyncExecuteRequest] {

private val HOST: String = "Host"
private val IGNORE_HEADERS: List[String] = List(HOST)

override def apply(request: AsyncExecuteRequest): Req =
  Req { requestBuilder =>
    transformMethod(request.request(), requestBuilder)
    transformHeaders(request.request(), requestBuilder)
    transformUrl(request.request(), requestBuilder)
    transformBody(request, requestBuilder)
  }

private def encodedPathAndQueryParams(sdkRequest: SdkHttpRequest) = {
  var encodedPath = sdkRequest.encodedPath
  if (StringUtils.isBlank(encodedPath)) encodedPath = "/"
  val encodedQueryParams = sdkRequest.encodedQueryParameters.toScala.map(queryParams => "?" + queryParams).getOrElse("")
  encodedPath + encodedQueryParams
}

private def getHostHeaderValue(request: SdkHttpRequest) =
  if (SdkHttpUtils.isUsingStandardPort(request.protocol, request.port)) request.host
else request.host + ":" + request.port

private def transformMethod(request: SdkHttpRequest, requestBuilder: RequestBuilder) =
  requestBuilder.setMethod(request.method().name().toUpperCase)

private def transformHeaders(request: SdkHttpRequest, requestBuilder: RequestBuilder) = {
  requestBuilder.addHeader(HOST, getHostHeaderValue(request))

  request.forEachHeader((name, values) => {
    if (!IGNORE_HEADERS.contains(name))
      values.forEach(value => requestBuilder.addHeader(name, value))
  })
}

private def transformUrl(request: SdkHttpRequest, requestBuilder: RequestBuilder) = {
  val uri = encodedPathAndQueryParams(request)
  requestBuilder.setUrl(request.protocol() + "://" + getHostHeaderValue(request) + uri)
}

private def transformBody(request: AsyncExecuteRequest, requestBuilder: RequestBuilder) = {
  val bodyCollector = new java.io.ByteArrayOutputStream()
  request.requestContentPublisher.subscribe(new Subscriber[ByteBuffer] {
    override def onSubscribe(s: Subscription): Unit = s.request(Long.MaxValue)

    override def onNext(item: ByteBuffer): Unit = while (item.hasRemaining) bodyCollector.write(item.get())

    override def onError(t: Throwable): Unit = requestBuilder.setBody("")

    override def onComplete(): Unit = requestBuilder.setBody(bodyCollector.toByteArray)
  })
  requestBuilder
}

}`

The code is in scala and uses java awssdk dependency "software.amazon.awssdk" % "s3" % "2.25.45",

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