lila/app/controllers/Blog.scala

package controllers

import play.api.mvc._, Results._

import io.prismic.Document

import lila.app._
import views._

object Blog extends LilaController {

  private def blogApi = Env.blog.api

  import Prismic._

  def index(ref: Option[String]) = Open { implicit ctx =>
    blogApi context ref flatMap { implicit prismic =>
      blogApi.recent(prismic.api, ref, 50) flatMap {
        case Some(response) => fuccess(Ok(views.html.blog.index(response)))
        case _              => notFound
      }
    }
  }

  def show(id: String, slug: String, ref: Option[String]) = Open { implicit ctx =>
    blogApi context ref flatMap { implicit prismic =>
      blogApi.one(prismic.api, ref, id) flatMap { maybeDocument =>
        checkSlug(maybeDocument, slug) {
          case Left(newSlug) => MovedPermanently(routes.Blog.show(id, newSlug, ref).url)
          case Right(doc)    => Ok(views.html.blog.show(doc))
        }
      } recoverWith {
        case e: RuntimeException if e.getMessage contains "Not Found" => notFound
      }
    }
  }

  def atom(ref: Option[String]) = Action.async { implicit req =>
    blogApi context ref flatMap { implicit prismic =>
      blogApi.recent(prismic.api, ref, 50) map {
        _ ?? (_.results)
      } map { docs =>
        Ok(views.xml.blog.atom(docs)) as XML
      }
    }
  }

  // -- Helper: Check if the slug is valid and redirect to the most recent version id needed
  private def checkSlug(document: Option[Document], slug: String)(callback: Either[String, Document] => Result)(implicit ctx: lila.api.Context) =
    document.collect {
      case document if document.slug == slug         => fuccess(callback(Right(document)))
      case document if document.slugs.contains(slug) => fuccess(callback(Left(document.slug)))
    } getOrElse notFound
}