An implicit connection for the whole system/project & FutureConverter

[Vladimir Kostyukov]

Hi Stephane and ReactiveMongo users,

I've been working on a project that combines Twitter's Finagle and ReactiveMongo Driver. I managed to solve two interesting issues: (a) converting Scala Future to Twitter's Future and (b) an implicit mongo connection for a whole project. I decided to put my findings here. Hope it will help someone.

On converting futures https://gist.github.com/vkostyukov/10164245

The 'FutureConverter' class might be used as follows:

val s = new Service[Req, Rep] with FutureConverter {

  def apply(req: Req): Future[Rep] = {

    val f = ... // a Scala Future returned by ReactiveMongo

    f.toTwitterFuture

  }

}

On implicit connection https://gist.github.com/vkostyukov/10285203

The documentation says there should a singleton 'MongoConnection' in the system. I found a truly Scala way of handling that. This is especially useful when the functionality is composed by services/modules which are Scala's objects. The usage example looks like this (example of usage with Finagle's Service):

object FooService extends Service[Request, Response]
     with ImplicitMongoConnection[Future[Response]] {

  // we have to explicitly import implicit value into the scope
  // we can do it at 'file' scope level
  import Main._

  def apply(req: Request): Future[Response] = withConnection { implicit connection =>
    // do all the magic here with 'connection'
    // and pack the result into a future
    Future.never
  }
}

The question to Stephane. Is it possible to have an ImplicitMongoConnection trait out-of-the-box in further releases. I found this tiny class really useful.

[Stephane Godbillon]

Hi Vladimir,

Thanks for sharing.  I'm not sure if ImplicitMongoConnection should be included directly in the library though; this use case seems a pretty specific and this trait is easy to write :)

Cheers,

-- Stephane Godbillon

Blog: http://stephane.godbillon.com

Twitter: https://twitter.com/sgodbillon

Github: https://github.com/sgodbillon

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