BaseDAO.scala

package core.dao

import scala.concurrent.Future

import play.api.Logger

import reactivemongo.core.commands.LastError
import reactivemongo.core.errors.DatabaseException

import core.db.MongoHelper
import core.exceptions._

/* Implicits */
import play.modules.reactivemongo.json.BSONFormats._

/**
 * Base DAO for MongoDB resources.
 * 
 * @author      Pedro De Almeida (almeidap)
 */
trait BaseDAO extends MongoHelper {

	val collectionName: String

	def ensureIndexes: Future[List[Boolean]]

	def Recover[S](operation: Future[LastError])(success: => S): Future[Either[ServiceException, S]] = {
		operation.map {
			lastError => lastError.inError match {
				case true => {
					Logger.error(s"DB operation did not perform successfully: [lastError=$lastError]")
					Left(DBServiceException(lastError))
				}
				case false => {
					Right(success)
				}
			}
		} recover {
			case exception =>
				Logger.error(s"DB operation failed: [message=${exception.getMessage}]")

				// TODO: better failure handling here
				val handling: Option[Either[ServiceException, S]] = exception match {
					case e: DatabaseException => {
						e.code.map(code => {
							Logger.error(s"DatabaseException: [code=${code}, isNotAPrimaryError=${e.isNotAPrimaryError}]")
							code match {
								case 10148 => {
									Left(OperationNotAllowedException("", nestedException = e))
								}
								case 11000 => {
									Left(DuplicateResourceException(nestedException = e))
								}
							}
						})
					}
				}
				handling.getOrElse(Left(UnexpectedServiceException(exception.getMessage, nestedException = exception)))
		}
	}
}

ContextHelper.scala

package core.helpers

import scala.concurrent.ExecutionContext

/**
 * Helper around implicit contexts.
 * 
 * @author      Pedro De Almeida (almeidap)
 */
trait ContextHelper {

	implicit def ec: ExecutionContext = ExecutionContext.Implicits.global

}

DBQueryBuilder.scala

package core.db

import play.api.libs.json.{Writes, Json, JsObject}

import reactivemongo.bson.BSONObjectID

/* Implicits */
import play.modules.reactivemongo.json.BSONFormats._

/**
 * Query builder wrapping common queries and MongoDB operators.
 *
 * TODO: create a real query `builder`
 * 
 * @author      Pedro De Almeida (almeidap)
 */
object DBQueryBuilder {

	def id(objectId: String): JsObject = id(BSONObjectID(objectId))

	def id(objectId: BSONObjectID): JsObject = Json.obj("_id" -> objectId)

	def set(field: String, data: JsObject): JsObject = set(Json.obj(field -> data))

	def set[T](field: String, data: T)(implicit writer: Writes[T]): JsObject = set(Json.obj(field -> data))

	def set(data: JsObject): JsObject = Json.obj("$set" -> data)

	def set[T](data: T)(implicit writer: Writes[T]): JsObject = Json.obj("$set" -> data)

	def push[T](field: String, data: T)(implicit writer: Writes[T]): JsObject = Json.obj("$push" -> Json.obj(field -> data))

	def pull[T](field: String, query: T)(implicit writer: Writes[T]): JsObject = Json.obj("$pull" -> Json.obj(field -> query))

	def unset(field: String): JsObject = Json.obj("$unset" -> Json.obj(field -> 1))

	def inc(field: String, amount: Int) = Json.obj("$inc" -> Json.obj(field -> amount))

	def or(criterias: JsObject*): JsObject = Json.obj("$or" -> criterias)

	def gt[T](field: String, value: T)(implicit writer: Writes[T]) = Json.obj(field -> Json.obj("$gt" -> value))

	def lt[T](field: String, value: T)(implicit writer: Writes[T]) = Json.obj(field -> Json.obj("$lt" -> value))

	def query[T](query: T)(implicit writer: Writes[T]): JsObject = Json.obj("$query" -> query)

	def orderBy[T](query: T)(implicit writer: Writes[T]): JsObject = Json.obj("$orderby" -> query)
}

DocumentDAO.scala

package core.dao

import org.joda.time.DateTime
import scala.concurrent.Future

import play.api.Logger
import play.api.libs.json._
import play.modules.reactivemongo.json.collection.JSONCollection

import reactivemongo.api.indexes.{Index, IndexType}
import reactivemongo.bson._

import core.db.DBQueryBuilder
import core.exceptions.ServiceException
import core.models.TemporalModel

/**
 * DAO for MongoDB documents.
 * 
 * @author      Pedro De Almeida (almeidap)
 */
trait DocumentDAO[T <: TemporalModel] extends BaseDAO {

	lazy val collection = db.collection[JSONCollection](collectionName)

	def insert(document: T)(implicit writer: Writes[T]): Future[Either[ServiceException, T]] = {
		document._id = Some(BSONObjectID.generate)
		document.created = Some(DateTime.now)
		document.updated = Some(DateTime.now)
		Logger.debug(s"Inserting document: [collection=$collectionName, data=$document]")
		Recover(collection.insert(document)) {
			document
		}
	}

	def find(query: JsObject = Json.obj())(implicit reader: Reads[T]): Future[List[T]] = {
		Logger.debug(s"Finding documents: [collection=$collectionName, query=$query]")
		collection.find(query).cursor[T].collect[List]()
	}

	def findById(id: String)(implicit reader: Reads[T]): Future[Option[T]] = findOne(DBQueryBuilder.id(id))

	def findById(id: BSONObjectID)(implicit reader: Reads[T]): Future[Option[T]] = findOne(DBQueryBuilder.id(id))

	def findOne(query: JsObject)(implicit reader: Reads[T]): Future[Option[T]] = {
		Logger.debug(s"Finding one: [collection=$collectionName, query=$query]")
		collection.find(query).one[T]
	}

	def update(id: String, document: T)(implicit writer: Writes[T]): Future[Either[ServiceException, T]] = {
		document.updated = Some(new DateTime())
		Logger.debug(s"Updating document: [collection=$collectionName, id=$id, document=$document]")
		Recover(collection.update(DBQueryBuilder.id(id), DBQueryBuilder.set(document))) {
			document
		}
	}

	def update(id: String, query: JsObject): Future[Either[ServiceException, JsObject]] = {
		val data = updated(query)
		Logger.debug(s"Updating by query: [collection=$collectionName, id=$id, query=$data]")
		Recover(collection.update(DBQueryBuilder.id(id), data)) {
			data
		}
	}

	def push[S](id: String, field: String, data: S)(implicit writer: Writes[S]): Future[Either[ServiceException, S]] = {
		Logger.debug(s"Pushing to document: [collection=$collectionName, id=$id, field=$field data=$data]")
		Recover(collection.update(DBQueryBuilder.id(id), DBQueryBuilder.push(field, data)
		)) {
			data
		}
	}

	def pull[S](id: String, field: String, query: S)(implicit writer: Writes[S]): Future[Either[ServiceException, Boolean]] = {
		Logger.debug(s"Pulling from document: [collection=$collectionName, id=$id, field=$field query=$query]")
		Recover(collection.update(DBQueryBuilder.id(id), DBQueryBuilder.pull(field, query))) {
			true
		}
	}

	def unset(id: String, field: String): Future[Either[ServiceException, Boolean]] = {
		Logger.debug(s"Unsetting from document: [collection=$collectionName, id=$id, field=$field]")
		Recover(collection.update(DBQueryBuilder.id(id), DBQueryBuilder.unset(field))) {
			true
		}
	}

	def remove(id: String): Future[Either[ServiceException, Boolean]] = remove(BSONObjectID(id))

	def remove(id: BSONObjectID): Future[Either[ServiceException, Boolean]] = {
		Logger.debug(s"Removing document: [collection=$collectionName, id=$id]")
		Recover(
			collection.remove(DBQueryBuilder.id(id))
		) {
			true
		}
	}

	def remove(query: JsObject, firstMatchOnly: Boolean = false): Future[Either[ServiceException, Boolean]] = {
		Logger.debug(s"Removing document(s): [collection=$collectionName, firstMatchOnly=$firstMatchOnly, query=$query]")
		Recover(
			collection.remove(query, firstMatchOnly = firstMatchOnly)
		) {
			true
		}
	}

	def updated(data: JsObject) = {
		data.validate((__ \ '$set).json.update(
			__.read[JsObject].map{ o => o ++ Json.obj("updated" -> DateTime.now) }
		)).fold(
			error => data,
			success => success
		)
	}

	def ensureIndex(
		key: List[(String, IndexType)],
		name: Option[String] = None,
		unique: Boolean = false,
		background: Boolean = false,
		dropDups: Boolean = false,
		sparse: Boolean = false,
		version: Option[Int] = None,
		options: BSONDocument = BSONDocument()) = {
		val index = Index(key, name, unique, background, dropDups, sparse, version, options)
		Logger.info(s"Ensuring index: $index")
		collection.indexesManager.ensure(index)
	}
}

FileDAO.scala

package core.dao

import scala.concurrent.Future

import play.api.Logger
import play.api.libs.iteratee.Enumerator
import play.api.libs.json.{Reads, Json, JsObject}

import reactivemongo.api.Cursor
import reactivemongo.api.gridfs.{DefaultFileToSave, FileToSave, ReadFile, GridFS}
import reactivemongo.bson.{BSONValue, BSONObjectID}

import core.db.DBQueryBuilder
import core.exceptions.ServiceException

/* Implicits */
import play.modules.reactivemongo.json.ImplicitBSONHandlers._
import reactivemongo.api.gridfs.Implicits.DefaultReadFileReader

/**
 * DAO for MongoDB `GridFS` files.
 * 
 * @author      Pedro De Almeida (almeidap)
 */
trait FileDAO extends BaseDAO {

	lazy val gfs = GridFS(db, collectionName)
	
	def insert(enumerator: Enumerator[Array[Byte]], file: DefaultFileToSave): Future[ReadFile[BSONValue]] = {
		gfs.save(enumerator, file)
	}

	def find(query: JsObject = Json.obj()): Cursor[ReadFile[BSONValue]] = {
		Logger.debug(s"Finding files: [collection=$collectionName, query=$query]")
		gfs.find(query)
	}

	def findById(id: String): Future[Option[ReadFile[BSONValue]]] = find(DBQueryBuilder.id(id)).headOption

	def findOne(query: JsObject = Json.obj()): Future[Option[ReadFile[BSONValue]]] = {
		Logger.debug(s"Finding one file: [collection=$collectionName, query=$query]")
		gfs.find(query).headOption
	}

	def removeById(id: String): Future[Either[ServiceException, Boolean]] = {
		Recover(gfs.remove(BSONObjectID(id))) {
			true
		}
	}
	
	def enumerate(file: ReadFile[_ <: BSONValue]): Enumerator[Array[Byte]] = {
		gfs.enumerate(file)
	}

	override def ensureIndexes = {
		// Let's build an index on our gridfs chunks collection if none:
		gfs.ensureIndex.map {
			case status =>
				Logger.info(s"GridFS index: [collection=$collectionName, status=$status]")
				List(status)
		}
	}
}

IdentifiableModel.scala

package core.models

import reactivemongo.bson.BSONObjectID

/**
 * Base model for `identifiable` documents.
 *
 * @author      Pedro De Almeida (almeidap)
 */
trait IdentifiableModel {
	var _id: Option[BSONObjectID]

	def identify = _id.map(value => value.stringify).getOrElse("")
}

MongoHelper.scala

package core.db

import play.api.Play.current
import play.modules.reactivemongo.ReactiveMongoPlugin

import reactivemongo.bson.{BSONObjectID, BSONValue}

import core.helpers.ContextHelper

/**
 * Helper around `MongoDB` resources.
 * 
 * @author  Pedro De Almeida (almeidap)
 */
trait MongoHelper extends ContextHelper{

	lazy val db = ReactiveMongoPlugin.db

}

object MongoHelper extends MongoHelper {

	def identify(bson: BSONValue) = bson.asInstanceOf[BSONObjectID].stringify

}

ServiceException.scala

package core.exceptions

/**
 * Trait for service exceptions.
 *
 * @author  Pedro De Almeida (almeidap)
 */
trait ServiceException extends Exception {
	val message: String
	val nestedException: Throwable
}

ServiceExceptions.scala

package core.exceptions

import reactivemongo.core.commands.LastError

import core.exceptions.ServiceException

/**
 * Service-related exceptions.
 * 
 * @author      Pedro De Almeida (almeidap)
 */
case class UnexpectedServiceException(
	message: String,
	nestedException: Throwable = null
) extends ServiceException

case class DBServiceException(
	message: String,
	lastError: Option[LastError] = None,
	nestedException: Throwable = null
) extends ServiceException

object DBServiceException {
	def apply(lastError: LastError): ServiceException = {
		DBServiceException(lastError.errMsg.getOrElse(lastError.message), Some(lastError))
	}
}

case class DuplicateResourceException(
	message: String = "error.duplicate.resource",
	nestedException: Throwable = null
) extends ServiceException

case class OperationNotAllowedException(
	message: String = "error.operation.not.allowed",
	nestedException: Throwable = null
) extends ServiceException

case class ResourceNotFoundException(
	id: String,
	message: String = "error.resource.not.found",
	nestedException: Throwable = null
) extends ServiceException

TemporalModel.scala

package core.models

import org.joda.time.DateTime

/**
  * Base model for `temporal` documents.
  *
  * @author      Pedro De Almeida (almeidap)
  */
trait TemporalModel extends IdentifiableModel {
	 var created: Option[DateTime]
	 var updated: Option[DateTime]
}