Merge pull request #56 from joshlemer/try-monad-error

Add TryMonad, implement a delegating TryBackend

2 files changed, 37 insertions, 0 deletions

diff --git a/core/src/main/scala/com/softwaremill/sttp/MonadError.scala b/core/src/main/scala/com/softwaremill/sttp/MonadError.scala
index 77c6235..5751382 100644
--- a/core/src/main/scala/com/softwaremill/sttp/MonadError.scala
+++ b/core/src/main/scala/com/softwaremill/sttp/MonadError.scala
@@ -41,7 +41,16 @@ object IdMonad extends MonadError[Id] {
   override protected def handleWrappedError[T](rt: Id[T])(
       h: PartialFunction[Throwable, Id[T]]): Id[T] = rt
 }
+object TryMonad extends MonadError[Try] {
+  override def unit[T](t: T): Try[T] = Success(t)
+  override def map[T, T2](fa: Try[T])(f: (T) => T2): Try[T2] = fa.map(f)
+  override def flatMap[T, T2](fa: Try[T])(f: (T) => Try[T2]): Try[T2] =
+    fa.flatMap(f)
 
+  override def error[T](t: Throwable): Try[T] = Failure(t)
+  override protected def handleWrappedError[T](rt: Try[T])(
+      h: PartialFunction[Throwable, Try[T]]): Try[T] = rt.recoverWith(h)
+}
 class FutureMonad(implicit ec: ExecutionContext)
     extends MonadAsyncError[Future] {
 
diff --git a/core/src/main/scala/com/softwaremill/sttp/TryBackend.scala b/core/src/main/scala/com/softwaremill/sttp/TryBackend.scala
new file mode 100644
index 0000000..7ec864f
--- /dev/null
+++ b/core/src/main/scala/com/softwaremill/sttp/TryBackend.scala
@@ -0,0 +1,28 @@
+package com.softwaremill.sttp
+
+import java.net.HttpURLConnection
+
+import scala.util.Try
+
+/** A Backend that safely wraps SttpBackend exceptions in Try's
+  *
+  * @param delegate An SttpBackend which to which this backend forwards all requests
+  * @tparam S The type of streams that are supported by the backend. `Nothing`,
+  *           if streaming requests/responses is not supported by this backend.
+  */
+class TryBackend[-S](delegate: SttpBackend[Id, S]) extends SttpBackend[Try, S] {
+  override def send[T](request: Request[T, S]): Try[Response[T]] =
+    Try(delegate.send(request))
+
+  override def close(): Unit = delegate.close()
+
+  override def responseMonad: MonadError[Try] = TryMonad
+}
+
+object TryHttpUrlConnectionBackend {
+  def apply(options: SttpBackendOptions = SttpBackendOptions.Default,
+            customizeConnection: HttpURLConnection => Unit = _ => ())
+    : SttpBackend[Try, Nothing] =
+    new TryBackend[Nothing](
+      HttpURLConnectionBackend(options, customizeConnection))
+}