web services - Converting a Future[T] to an always-successful Future[Option[T]] -

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the motivating use-case have in mind follows:

  • in play framework controller, calling play's ws. produces potentially-failing future
  • i want handle separate cases of ws request succeeding vs failing. in both cases, want produce play response (likely future[response])

what think trying is:

  • asynchronously, after future completes, unconditionally handle completion
  • produce future[response] corresponding desired response

i don't believe can use future.map because need customize handling of failure case , not pass on future's failure.

if have alternative suggestions how solve cleanly, please let me know.

you're looking future.recover.

val wsresponse: future[wsresponse] = ???  wsresponse map { response =>   // success case   ok(response.json) } recover {   // failure case, turn throwable response   case t: throwable =>     internalservererror(t.getmessage) }

recover takes partial function throwable => t. in case, t option[response] can construct according whatever business logic in both success , fail cases.

do note play's ws library return successful future failed http call, if (e.g.,) call returns 404 external server, map function still need error handling.


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