+doc #20699 improve docs for akka-http (#20722)

Made imports in docs snippets more complete and a few minor improvements

akka-docs/rst/scala/code/docs/http/scaladsl/HttpServerExampleSpec.scala

@@ -5,10 +5,6 @@
 package docs.http.scaladsl
 
 import akka.event.LoggingAdapter
-import akka.http.scaladsl.Http.ServerBinding
-import akka.http.scaladsl.model._
-import akka.stream.ActorMaterializer
-import akka.stream.scaladsl.{ Flow, Sink }
 import akka.testkit.TestActors
 import docs.CompileOnlySpec
 import org.scalatest.{ Matchers, WordSpec }
@@ -44,37 +40,50 @@ class HttpServerExampleSpec extends WordSpec with Matchers
   "binding-failure-high-level-example" in compileOnlySpec {
     import akka.actor.ActorSystem
     import akka.http.scaladsl.Http
+    import akka.http.scaladsl.Http.ServerBinding
     import akka.http.scaladsl.server.Directives._
     import akka.stream.ActorMaterializer
 
-    implicit val system = ActorSystem()
-    implicit val materializer = ActorMaterializer()
-    // needed for the future onFailure in the end
-    implicit val executionContext = system.dispatcher
+    import scala.concurrent.Future
 
-    val handler = get {
-      complete("Hello world!")
+    object WebServer {
+      def main(args: Array[String]) {
+        implicit val system = ActorSystem()
+        implicit val materializer = ActorMaterializer()
+        // needed for the future onFailure in the end
+        implicit val executionContext = system.dispatcher
+
+        val handler = get {
+          complete("Hello world!")
+        }
+
+        // let's say the OS won't allow us to bind to 80.
+        val (host, port) = ("localhost", 80)
+        val bindingFuture: Future[ServerBinding] =
+          Http().bindAndHandle(handler, host, port)
+
+        bindingFuture.onFailure {
+          case ex: Exception =>
+            log.error(ex, "Failed to bind to {}:{}!", host, port)
+        }
+      }
     }
-
-    // let's say the OS won't allow us to bind to 80.
-    val (host, port) = ("localhost", 80)
-    val bindingFuture: Future[ServerBinding] =
-      Http().bindAndHandle(handler, host, port)
-
-    bindingFuture.onFailure {
-      case ex: Exception =>
-        log.error(ex, "Failed to bind to {}:{}!", host, port)
-    }
-
   }
 
   // mock values:
-  import akka.http.scaladsl.Http
-  import akka.actor.ActorSystem
-  val handleConnections: Sink[Http.IncomingConnection, Future[Http.ServerBinding]] =
+  val handleConnections = {
+    import akka.stream.scaladsl.Sink
     Sink.ignore.mapMaterializedValue(_ => Future.failed(new Exception("")))
+  }
 
   "binding-failure-handling" in compileOnlySpec {
+    import akka.actor.ActorSystem
+    import akka.http.scaladsl.Http
+    import akka.http.scaladsl.Http.ServerBinding
+    import akka.stream.ActorMaterializer
+
+    import scala.concurrent.Future
+
     implicit val system = ActorSystem()
     implicit val materializer = ActorMaterializer()
     // needed for the future onFailure in the end
@@ -102,11 +111,8 @@ class HttpServerExampleSpec extends WordSpec with Matchers
     import akka.actor.ActorSystem
     import akka.actor.ActorRef
     import akka.http.scaladsl.Http
-    import akka.http.scaladsl.model.HttpEntity
-    import akka.http.scaladsl.model.ContentTypes
-    import akka.http.scaladsl.server.Directives._
     import akka.stream.ActorMaterializer
-    import scala.io.StdIn
+    import akka.stream.scaladsl.Flow
 
     implicit val system = ActorSystem()
     implicit val materializer = ActorMaterializer()
@@ -132,8 +138,9 @@ class HttpServerExampleSpec extends WordSpec with Matchers
   "connection-stream-failure-handling" in compileOnlySpec {
     import akka.actor.ActorSystem
     import akka.http.scaladsl.Http
-    import akka.http.scaladsl.model.{ ContentTypes, HttpEntity }
+    import akka.http.scaladsl.model._
     import akka.stream.ActorMaterializer
+    import akka.stream.scaladsl.Flow
 
     implicit val system = ActorSystem()
     implicit val materializer = ActorMaterializer()
@@ -203,6 +210,7 @@ class HttpServerExampleSpec extends WordSpec with Matchers
   }
 
   "low-level-server-example" in compileOnlySpec {
+    import akka.actor.ActorSystem
     import akka.http.scaladsl.Http
     import akka.http.scaladsl.model.HttpMethods._
     import akka.http.scaladsl.model._
@@ -286,7 +294,9 @@ class HttpServerExampleSpec extends WordSpec with Matchers
   }
 
   "minimal-routing-example" in compileOnlySpec {
+    import akka.actor.ActorSystem
     import akka.http.scaladsl.Http
+    import akka.http.scaladsl.model._
     import akka.http.scaladsl.server.Directives._
     import akka.stream.ActorMaterializer
     import scala.io.StdIn
@@ -319,13 +329,14 @@ class HttpServerExampleSpec extends WordSpec with Matchers
 
   "long-routing-example" in compileOnlySpec {
     //#long-routing-example
-    import akka.actor.ActorRef
+    import akka.actor.{ActorRef, ActorSystem}
     import akka.http.scaladsl.coding.Deflate
     import akka.http.scaladsl.marshalling.ToResponseMarshaller
     import akka.http.scaladsl.model.StatusCodes.MovedPermanently
     import akka.http.scaladsl.server.Directives._
     import akka.http.scaladsl.unmarshalling.FromRequestUnmarshaller
     import akka.pattern.ask
+    import akka.stream.ActorMaterializer
     import akka.util.Timeout
 
     // types used by the API routes
@@ -427,6 +438,7 @@ class HttpServerExampleSpec extends WordSpec with Matchers
 
   "stream random numbers" in compileOnlySpec {
     //#stream-random-numbers
+    import akka.actor.ActorSystem
     import akka.stream.scaladsl._
     import akka.util.ByteString
     import akka.http.scaladsl.Http
@@ -483,15 +495,15 @@ class HttpServerExampleSpec extends WordSpec with Matchers
   "interact with an actor" in compileOnlySpec {
     //#actor-interaction
     import akka.actor.ActorSystem
-    import akka.actor.Props
-    import scala.concurrent.duration._
-    import akka.util.Timeout
-    import akka.pattern.ask
-    import akka.stream.ActorMaterializer
     import akka.http.scaladsl.Http
+    import akka.http.scaladsl.model.StatusCodes
     import akka.http.scaladsl.server.Directives._
     import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport._
+    import akka.pattern.ask
+    import akka.stream.ActorMaterializer
+    import akka.util.Timeout
     import spray.json.DefaultJsonProtocol._
+    import scala.concurrent.duration._
     import scala.io.StdIn
 
     object WebServer {