Add support for cats effect with AHC backend

1 files changed, 61 insertions, 0 deletions

diff --git a/async-http-client-handler/cats/src/main/scala/com/softwaremill/sttp/asynchttpclient/cats/CatsAsyncHttpClientHandler.scala b/async-http-client-handler/cats/src/main/scala/com/softwaremill/sttp/asynchttpclient/cats/CatsAsyncHttpClientHandler.scala
new file mode 100644
index 0000000..cfd9c5b
--- /dev/null
+++ b/async-http-client-handler/cats/src/main/scala/com/softwaremill/sttp/asynchttpclient/cats/CatsAsyncHttpClientHandler.scala
@@ -0,0 +1,61 @@
+package com.softwaremill.sttp.asynchttpclient.cats
+
+import java.nio.ByteBuffer
+
+import cats.effect._
+import com.softwaremill.sttp.asynchttpclient.AsyncHttpClientHandler
+import com.softwaremill.sttp.{MonadAsyncError, SttpHandler}
+import org.asynchttpclient.{
+  AsyncHttpClient,
+  AsyncHttpClientConfig,
+  DefaultAsyncHttpClient
+}
+import org.reactivestreams.Publisher
+
+import scala.language.higherKinds
+
+class CatsAsyncHttpClientHandler[F[_]: Async](asyncHttpClient: AsyncHttpClient,
+                                              closeClient: Boolean)
+    extends AsyncHttpClientHandler[F, Nothing](asyncHttpClient,
+                                               new AsyncMonad,
+                                               closeClient) {
+  override protected def streamBodyToPublisher(
+      s: Nothing): Publisher[ByteBuffer] = s // nothing is everything
+
+  override protected def publisherToStreamBody(
+      p: Publisher[ByteBuffer]): Nothing =
+    throw new IllegalStateException("This handler does not support streaming")
+}
+
+object CatsAsyncHttpClientHandler {
+
+  def apply[F[_]: Async](): SttpHandler[F, Nothing] =
+    new CatsAsyncHttpClientHandler(new DefaultAsyncHttpClient(),
+                                   closeClient = true)
+
+  def usingConfig[F[_]: Async](
+      cfg: AsyncHttpClientConfig): SttpHandler[F, Nothing] =
+    new CatsAsyncHttpClientHandler(new DefaultAsyncHttpClient(cfg),
+                                   closeClient = true)
+
+  def usingClient[F[_]: Async](
+      client: AsyncHttpClient): SttpHandler[F, Nothing] =
+    new CatsAsyncHttpClientHandler(client, closeClient = false)
+}
+
+private[cats] class AsyncMonad[F[_]](implicit F: Async[F])
+    extends MonadAsyncError[F] {
+
+  override def async[T](
+      register: ((Either[Throwable, T]) => Unit) => Unit): F[T] =
+    F.async(register)
+
+  override def unit[T](t: T): F[T] = F.pure(t)
+
+  override def map[T, T2](fa: F[T], f: (T) => T2): F[T2] = F.map(fa)(f)
+
+  override def flatMap[T, T2](fa: F[T], f: (T) => F[T2]): F[T2] =
+    F.flatMap(fa)(f)
+
+  override def error[T](t: Throwable): F[T] = F.raiseError(t)
+}