Akka Http. Transform API response and forward it - scala

Question

I have an Akka-Http route where I'm calling Bing Search API. I want to add some extra records to the result, before sending the response to client. I'm using circe to handle json.
Here is the code which doesn't work but illustrates the idea:
val extraData = Map("key1"->"value1","key2"->"val2").asJson
val query = URLEncoder.encode(q, "utf8")
val responseFuture: Future[HttpResponse] = Http().singleRequest(
HttpRequest(uri = "https://api.cognitive.microsoft.com/bing/v7.0/search?q=" + query)
.withHeaders(RawHeader("Ocp-Apim-Subscription-Key", k1)))
val alteredResponse = responseFuture.map{ response => {
response.entity.toStrict(2 seconds) flatMap { e =>
e.dataBytes
.runFold(ByteString.empty) { case (acc, b) => acc ++ b }
.map(k => parse(k.utf8String)
match {
case Left(failure) => "Can't parse"
case Right(json) => Try {
json.hcursor.withFocus{
_.mapObject(x =>
x.add("extraData",extraData)
)
}
}}
)
}
}}
complete(alteredResponse)
Is it a good approach to take ? How can I get it to work ?

Answer 1

I ended up using flatMap and creating HttpResponse object manually:
val responseFuture: Future[HttpResponse] = Http().singleRequest(
HttpRequest(uri = "https://api.cognitive.microsoft.com/bing/v7.0/search?q=" + query)
.withHeaders(RawHeader("Ocp-Apim-Subscription-Key", k1)))
.flatMap{ response => {
response.entity.toStrict(2 seconds) flatMap { e =>
e.dataBytes
.runFold(ByteString.empty) { case (acc, b) => acc ++ b }
.map(k => parse(k.map(_.toChar).mkString)
match {
case Left(failure) => HttpResponse(
StatusCodes.OK,
List(),
HttpEntity("NO RESULTS".map(_.toByte).toArray),
HttpProtocol("HTTP/1.1")
)
case Right(json) => {
json.hcursor.withFocus{
_.mapObject(x =>
x.add("extraData",extraData)
)
}.top match {
case Some(jsn) => {
HttpResponse(
StatusCodes.OK,
List(headers.`Content-Type`(ContentType(MediaTypes.`application/json`,() => HttpCharsets.`UTF-8`))),
HttpEntity(jsn.noSpaces.toCharArray.map(_.toByte)),
HttpProtocol("HTTP/1.1")
)
}
}
}}
)
}
}}
complete(responseFuture)
When converting response Bytes from Bing, i tried to use .utf8String function, but it messed up the Json, so I eneded up parsing bytes with map.(_toChar).mkString.
If there is a better way of writing this code, it would be nice to see it. Thanks.