http4s/http4s

We're on discord at http://sca.la/typeleveldiscord (Please do not use threads)

Christopher Davenport

@ChristopherDavenport

Sane error messaging, that seems unreasonable.

This is FP. 234sekjfasdf or it didn’t happen.

Fabio Labella

@SystemFw

with just that code if you do logMe("hello") you get "Magnet[F] does not get parameters"

let me see if I can remember how to fix that

(if it's fixable, lost track)

Christopher Davenport

@ChristopherDavenport

To be fair, logMe is definitely incorrect in the way scala does type identification in the first place.

Fabio Labella

@SystemFw

mm I think in the end I settled for just renaming apply to something else to get implicitNotFound-driven errors to work, can't quite remember anymore

I think the reason that makes it work in the correct scenario (it doesn't necessarily go through implicit search, but goes via the implicit conversion, thus avoiding the confusion between the input and the implicit parameter), it's also why implicitNotFound does not work (if it fails the implicit search you simply do not trigger the conversion)

Fabio Labella

@SystemFw

ah! I managed (just for the laughs though)

  def yolo = logMe[IO]("hello")
  // scala> yolo.unsafeRunSync
  // hello

  def well = logMe("hello")
Users/fabio/projects/playground/src/main/scala/Playground.scala:57: Specify `IO` there: `logMe[IO]("hello")`
[error]   def well = logMe("hello")

  def logMe[F[_]]: Magnet[F] = new Magnet[F]

  class Magnet[F[_]]
  trait LowPrio {
    @annotation.implicitNotFound("""Specify `IO` there: `logMe[IO]("hello")`""")
    trait Error
    class Catch[F[_]] {
      def apply(s: String, logAction: String => F[Unit] = ???)(implicit ev: Error) =
        ???
    }

    implicit def conv2[F[_]](m: Magnet[F]): Catch[F] =
      new Catch[F]
  }
  object Magnet extends LowPrio {
    implicit def conv[F[_]: Sync](m: Magnet[F]): LogMePartiallyApplied[F] =
      new LogMePartiallyApplied[F]

    class LogMePartiallyApplied[F[_]: Sync] {
      def apply(s: String, logAction: String => F[Unit] = { s =>
        Sync[F].delay(println(s))
      }) =
        logAction(s)
    }
  }

enjoy

Ross A. Baker

@rossabaker

So getting back to working around that error, I think the two questions are:
1) Do we want to be able to inspect the context on the builder?
2) What failure mode do we want if the default is bad and was not overridden?

Fabio Labella

@SystemFw

when you talk about 1), is the problem the fact that if you suspend the creation of SSLContext I can't see what's there without building one?

Ross A. Baker

@rossabaker

Yes.

Valentin Willscher

@valenterry

Is there a recommended way to unit test routes that returns streams of data?

I know that I can use the http4s web client for more integration-like tests, but I couldn't figure out how to test a routes (which is Kleisli) directly

The reason is that all the helper functions like HttpRoutes.of return org.http4s.package$#HttpRouteswhich is type HttpRoutes[F[_]] = Http[OptionT[F, ?], F] with Http being type Http[F[_], G[_]] = Kleisli[F, Request[G], Response[G]]

That means, the result will have Request[G] and Response[G] with the same effect - but my request is supposed to work with IO and the response should be a stream.

I can build that up myself, but I wondered if there is a better or already existing solution

Ross A. Baker

@rossabaker

orNotFound (on implicits) gets you to F[Response[F]]

map(_.body) gets you to F[Stream[F, Byte]]

Stream.eval gets you to Stream[F, Stream[F, Byte]]

And flatten gets you to Stream[F, Byte]

There's probably a shorter way but I just woke up and my brain is still booting.

Ross A. Baker

@rossabaker

I revisted that SSL issue. We can avoid that lazy hack in a binary-compatible way.

This as a default argument gets the job done: Try(SSLContext.getDefault()).toOption. The question is whether to log a warning that the default failed.

I'll open a PR and can discuss more there.

Ross A. Baker

@rossabaker

Nuts, my idea breaks semantics.

Christopher Davenport

@ChristopherDavenport

Yup, that’s not delayed.

Ross A. Baker

@rossabaker

I was going to add support for disabling SSL to get rid of the lazy hack.

Christopher Davenport

@ChristopherDavenport

I think that new solution is much nicer.,

Ross A. Baker

@rossabaker

It's a subtle change, so I moved that to 0.21. I think it would have been binary compatible.

Jakub Kozłowski

@kubukoz

Why was Uri.uri deprecated? The interpolator is nice, but it's quite hard to find the right import that doesn't end with an underscore

having two possible ways to write an URI from a string literal was actually cool

Gavin Bisesi

@Daenyth

Hey, what's the shape of the landscape in terms of AWS request signing?

Christopher Davenport

@ChristopherDavenport

I thought someone had implemented that somewhere.

Gavin Bisesi

@Daenyth

Assume I want to add a project-internal client for an api that doesn't have a pre-existing api client, but uses that signing method - is there something I can depend on that drops the middleware in?

I implemented it myself once before but was sad about it

and then when I brought it up here I heard there were some approaches

There's aws4s but I'm not convinced that I want to base my api client on their model, and I don't know to what extent the signing can be abstracted out

because I also need to go through the LWA (SSO) system, which I think the public-facing services don't force

Christopher Davenport

@ChristopherDavenport

Haven’t played with it, sorry hopefully someone who has can be more informative.

Abhishek Srivastava

@abhishes_twitter

I wrote this code

BlazeClientBuilder[IO](global).resource.use { client =>
for {
    response <- foo( client)
 } yield ()
 }

def foo(client: Client) : IO[String] = ...

this gives me error trait Client takes type parameters

How should I define the signature of method foo?

oh wait .... got it def foo(client: Client[IO]) : IO[String] = ...

Henri Cook

@henricook

Hi all, i'm hoping to receive a POST of a JSON object, i'm struggling to find an example of a post endpoint that parses a json object modelled by a case class though, can anyone point me in the right direction?

Fabio Labella

@SystemFw

https://http4s.org/v0.20/json/

check the "putting it all together" section towards the bottom of the page

Henri Cook

@henricook

ahhh i hadn't read that far, i'd stopped/got confused around Decoding JSON to a case class

Where communities thrive

People

Repo info

Activity