MongoDB Salat plugin for Play Framework 2

Salat is a ORM for MongoDBs scala driver called Casbah.

The plugin's functionality simpifies the use of salat by presenting a simple "play style" configuration and binders for ObjectId

Installation

Use g8 to start a new salat enabled play project

Install g8 on OSX using homebrew

brew update && brew install giter8

Or read about the other ways to install giter8 here

Then run

g8 leon/play-salat.g8

It will ask you a couple of questions, and your ready to rock 'n roll.

Manual installation

Start by adding the plugin, in your project/Build.scala

val appDependencies = Seq(
  "se.radley" %% "play-plugins-salat" % "1.1"
)

Then we can add the implicit converstions to and from ObjectId by adding to the routesImport and add ObjectId to all the templates

val main = PlayProject(appName, appVersion, appDependencies, mainLang = SCALA).settings(
  routesImport += "se.radley.plugin.salat.Binders._",
  templatesImport += "org.bson.types.ObjectId"
)

We now need to register the plugin, this is done by creating(or appending) to the conf/play.plugins file

500:se.radley.plugin.salat.SalatPlugin

We continue to edit the conf/application.conf file. We need to disable some plugins that we don't need. Add these lines:

dbplugin = disabled
evolutionplugin = disabled
ehcacheplugin = disabled

Configuration

now we need to setup our connections. The plugin is modeled after how plays DB plugin is built.

mongodb.default.db = "mydb"
# Optional values
#mongodb.default.host = "127.0.0.1"
#mongodb.default.port = 27017
#mongodb.default.user = "leon"
#mongodb.default.password = "123456"

# MongoURI
# ~~~~~
# a MongoURI can also be used http://www.mongodb.org/display/DOCS/Connections
# mongodb.default.uri = "mongodb://127.0.0.1:27017,mongodb.org:1337/salat-test"

# WriteConcern
# ~~~~~
# Can be any of the following
#
# fsyncsafe - Exceptions are raised for network issues and server errors; Write operations wait for the server to flush data to disk.
# replicassafe - Exceptions are raised for network issues and server errors; waits for at least 2 servers for the write operation.
# safe - Exceptions are raised for network issues and server errors; waits on a server for the write operation.
# normal - Exceptions are raised for network issues but not server errors.

#mongodb.default.writeconcern = "safe"

# Replica sets
# ~~~~~
# http://www.mongodb.org/display/DOCS/Why+Replica+Sets
#
# To user a replicaset instead of a single host, omit optional values and use the configuration below instead.
# Since replica sets use public key authentication, user and password won't work together with the replicaset option.

#mongodb.default.replicaset {
#    host1.host = "10.0.0.1"
#
#    host2.host = "10.0.0.2"
#    host2.port = 27018
#}

More that one DB?

If you would like to connect to two databases you need to create two source names

mongodb.myotherdb.db = "otherdb"

Then you can call mongoCollection("collectionname", "myotherdb")

What a model looks like

All models must be case classes otherwise salat doesn't know how to properly transform them into MongoDBObject's

package models

import play.api.Play.current
import java.util.Date
import com.novus.salat._
import com.novus.salat.annotations._
import com.novus.salat.dao._
import com.mongodb.casbah.Imports._
import se.radley.plugin.salat._
import mongoContext._

case class User(
  id: ObjectId = new ObjectId,
  username: String,
  password: String,
  address: Option[Address] = None,
  added: Date = new Date(),
  updated: Option[Date] = None,
  deleted: Option[Date] = None,
  @Key("company_id")company: Option[ObjectId] = None
)

object User extends ModelCompanion[User, ObjectId] {
  val dao = new SalatDAO[User, ObjectId](collection = mongoCollection("users")) {}

  def findOneByUsername(username: String): Option[User] = dao.findOne(MongoDBObject("username" -> username))
  def findByCountry(country: String) = dao.find(MongoDBObject("address.country" -> country))
}

Capped Collections

If you want to use capped collections check this out

package models

import play.api.Play.current
import java.util.Date
import com.novus.salat._
import com.novus.salat.annotations._
import com.novus.salat.dao._
import com.mongodb.casbah.Imports._
import se.radley.plugin.salat._
import mongoContext._

case class LogItem(
  id: ObjectId = new ObjectId,
  message: String
)

object LogItem extends ModelCompanion[LogItem, ObjectId] {
  val dao = new SalatDAO[LogItem, ObjectId](collection = mongoCappedCollection("logitems", 1000)) {}
}

GridFS

If you want to store things in gridfs you can do this

package models

import play.api.Play.current
import se.radley.plugin.salat._
import mongoContext._

val files = gridFS("myfiles")

Mongo Context

All models must contain an implicit salat Context. The context is somewhat like a hibernate dialect. You can override mapping names and configure how salat does it's type hinting. read more about it here

In the sample there is a custom mongoContext, partly because we need to add plays classloader to salat so it knows when to reload it's graters, but also so we can override all models id fields to be serialized to MongoDB's _id.

Sample

Enums?

If you're using Scala Enumerations have a look at my play-enumeration project.

play-enumeration

adamchandra/play-salat