GrasswireUrlShortener.scala

package com.grasswire.grasswireurlshortener

import akka.actor.ActorSystem
import com.typesafe.config.ConfigFactory
import org.apache.commons.validator.routines.UrlValidator
import spray.http.StatusCodes
import spray.routing._
import scala.util.Random
import scalaz.concurrent._

object GrasswireUrlShortener extends App with SimpleRoutingApp {
  implicit val system = ActorSystem("grasswire-url-shortener")
  implicit val redis = scredis.Redis(ConfigFactory.load(), "redis")

  startServer("0.0.0.0", 8080) {
    path(Rest) { r =>
      get {
        redirectShortUrl(r)
      } ~ post {
        createShortUrl(r)
      }
    }
  }

  def redirectShortUrl(path: String)(implicit redis: scredis.Redis) = (ctx: RequestContext) => {
    Future.now {
      redis.withClient(_.get[String](path))
    }.runAsync(_.map(ctx.redirect(_, StatusCodes.MovedPermanently))
      .getOrElse(ctx.complete(StatusCodes.NotFound)))
  }

  def createShortUrl(path: String)(implicit redis: scredis.Redis) = (ctx: RequestContext) => {
    Task {
      val validator = new UrlValidator(List("http","https").toArray)
      if(validator.isValid(path)) {
        val random = Random.alphanumeric.take(7).mkString
        redis.withClient(_.set(random, path))
        random
      } else {
        throw new Exception("The supplied url is invalid.")
      }
    }.runAsync(_.fold(l => ctx.reject(ValidationRejection("Invalid url provided", Some(l))), r => ctx.complete(s"http://mydomain.com/$r")))
  }
}