QueryParamDecoder instance for http4s

[gabro]

FUUIDVar from fuuid-http4s provides support for extracting path params, but there's no support for extracting query params.

It would essentially be something like

implicit val fuuidQueryParamDecoder: QueryParamDecoder[FUUID] =
  QueryParamDecoder.fromUnsafeCast(v => FUUID.fromString(v.value).right.get)("FUUID")

and use

object UserIdQueryParamMatcher extends QueryParamDecoderMatcher[FUUID]("userId")

val routes: HttpRoutes[F] = HttpRoutes.of[F]({
  case req @ GET -> Root / "get" :? UserIdQueryParamMatcher(userId) =>
    for {
      result <- controller.get(userId)
      res <- result.map(Ok(_)).getOrElse(NotFound())
    } yield res
})

@ChristopherDavenport if you agree this is useful, I can send a PR.

[ChristopherDavenport]

Sounds great! Are you on 0.1 or the 0.2 milestones?

If you target 0.1 I can merge it forward or only make it available in the new one. I'll leave that choice up to you.

Regardless it would make a great addition I believe. I imagine you are not alone in this desire.

[gabro]

I'm on 0.2.0-M2 currently, I'll add it to current master and I guess it can be added to the 0.1.0 series if there's demand.

[ChristopherDavenport]

Works for me! 😄