java-ngrok Example - Play (Scala)

This is an example project that shows how to easily integrate java-ngrok with Play.

Application Integration

Register an eager Singleton in the app's base Module.

class Module extends AbstractModule {
  override def configure(): Unit = {
    bind(classOf[NgrokApplicationLifecycle]).asEagerSingleton()
  }
}

Then create a NgrokApplicatinLifecycle class. If ngrok.enabled config flag is set, we want to initialize java-ngrok when Play is booting in a dev environment.

@Singleton
class NgrokApplicationLifecycle @Inject()(config: Configuration, lifecycle: ApplicationLifecycle) {
  private val environment: String = config.getOptional[String]("environment").getOrElse("production")
  private val ngrokEnabled: Boolean = config.getOptional[Boolean]("ngrok.enabled").getOrElse(false)
  private val region: String = config.getOptional[String]("ngrok.region").orNull

  // java-ngrok will only be installed, and should only ever be initialized, in a dev environment
  if (environment.equals("dev") && ngrokEnabled) {
    val javaNgrokConfig: JavaNgrokConfig = new JavaNgrokConfig.Builder()
      .withRegion(if (nonNull(region)) Region.valueOf(region.toUpperCase) else null)
      .build
    val ngrokClient: NgrokClient = new NgrokClient.Builder()
      .withJavaNgrokConfig(javaNgrokConfig)
      .build

    val port: Int = config.getOptional[Int]("http.port").getOrElse(9000)

    val createTunnel: CreateTunnel = new CreateTunnel.Builder()
      .withAddr(port)
      .build
    val tunnel: Tunnel = ngrokClient.connect(createTunnel)

    println(s" * ngrok tunnel \"${tunnel.getPublicUrl}\" -> \"http://localhost:$port\"")
  }
}

Pass parameters to our Play application through our config file (including making .ngrok.io an allowed host):

ngrok {
    enabled=true
}
play.filters.hosts {
  allowed = [".ngrok.io", "localhost:9000"]
}

Now Play can be started by the usual means, setting ngrok.enabled in the config to open a tunnel.

1. Run make build to build the application
2. Start application with sbt run
3. Check the logs for the ngrok tunnel's public URL, which should tunnel to http://localhost:9000