Akka HTTP

How to use Akka HTTP

Akka HTTP is a toolkit for building reactive web applications on top of the Akka actor model. Here are the steps to use Akka HTTP:

1. Add Akka HTTP dependency: Start by adding the Akka HTTP dependency to your build configuration, depending on your build system (e.g., Maven, Gradle, SBT).

2. Create routes: Define your HTTP endpoints using the Route DSL. A route defines a request handler and can decompose incoming requests into their constituent parts.

3. Bind to an interface: Use the Http().bindAndHandle() method to bind the route to a specific network interface and port.

4. Handle requests: Once Akka HTTP is running, it will handle incoming requests according to your defined routes. Incoming requests will be handled in a reactive, non-blocking way, thanks to the underlying Akka actor model.

For example, here's some code that defines a simple "Hello, world" endpoint:

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.server.Directives._
import scala.io.StdIn

object HelloWorldServer {
  def main(args: Array[String]) {

    implicit val system = ActorSystem("hello-world-system")
    implicit val executionContext = system.dispatcher

    val route =
      path("hello") {
        get {
          complete("Hello, world!")
        }
      }

    val bindingFuture = Http().bindAndHandle(route, "localhost", 8080)

    println(s"Server online at http://localhost:8080/\nPress RETURN to stop...")
    StdIn.readLine()

    bindingFuture
      .flatMap(_.unbind())
      .onComplete(_ => system.terminate())
  }
}

This code defines a single endpoint at

that responds with to GET requests. It binds the route to the interface on port . When the program starts, it prints a message indicating the URL where the server is running. The server runs until the user presses the key.

This is just a simple example of what Akka HTTP can do. With its powerful routing DSL and support for reactive streams, you can build complex, highly scalable web applications with ease.