ferrlin / akka-sse

akka-sse adds support for Server-Sent Events to akka-http

akka-sse

akka-sse adds support for [Server-Sent Events](http://www.w3.org/TR/eventsource/#event-stream-interpretation SSE specification) (SSE) to akka-http.

Installation

akka-sse depends on akka-http 1.0-RC2.

Grab it while it's hot:

// All releases including intermediate ones are published here,
// final ones are also published to Maven Central.
resolvers += "hseeberger at bintray" at "http://dl.bintray.com/hseeberger/maven"

libraryDependencies ++= List(
  "de.heikoseeberger" %% "akka-sse" % "0.13.0",
  ...
)

Usage

First, mix EventStreamMarshalling into your request handling classes or actors, e.g.:

class HttpService
    extends Actor
    with Directives
    with EventStreamMarshalling { ... }

Then, define an implicit view from your domain events to ServerSentEvents, e.g.:

implicit def flowEventToServerSentEvent(event: Flow.Event): ServerSentEvent =
  event match {
    case messageAdded: Flow.MessageAdded =>
      val data = PrettyPrinter(jsonWriter[Flow.MessageAdded].write(messageAdded))
      ServerSentEvent(data, "added")
  }

Finally, simply complete a request to get an SSE stream with a akka.stream.scaladsl.Source of your domain events, e.g.:

private def messages: Route =
  path("messages") {
    get {
      complete {
        Source(ActorPublisher[Flow.Event](createFlowEventPublisher()))
      }
    }
  }

There's also early support for consuming server-side events via EventStreamUnmarshalling. Take a look at the example project for details.

A complete demo using akka-sse is Reactive Flows. Have fun, and please report any issues, suggestions, complaints.

Contribution policy

Contributions via GitHub pull requests are gladly accepted from their original author. Along with any pull requests, please state that the contribution is your original work and that you license the work to the project under the project's open source license. Whether or not you state this explicitly, by submitting any copyrighted material via pull request, email, or other means you agree to license the material under the project's open source license and warrant that you have the legal authority to do so.

License

This code is open source software licensed under the Apache 2.0 License.