Play is a stateless web framework for Scala and Java that provides a full stack solution for web development. It includes features like JSON integration, RESTful APIs by default, and a standard application layout. The framework uses routes files to map URLs to controller actions. Templates are used to render views and are written in Scala. Controllers handle business logic and call models and queries to interact with databases. Models define the application's domain and queries. Play supports MongoDB out of the box via ReactiveMongo.

1. Malti Yadav
malti@knoldus.com
Play ! Framework
Introduction & Highlights

2. Quick Overview

Stateless framework

Integration of JSON

Full stack web framework

Compilation and Exact Error

Lots of build in feature for fast developement

Urls are entry poin to application

RESTful by default

3. Architecture

4. Setup play project

5. Standard Application Layout
app → Application sources
└ assets → Compiled asset sources
└ stylesheets → Typically LESS CSS sources
└ javascripts → Typically CoffeeScript sources
└ controllers → Application controllers
└ models → Application business layer
└ views → Templates
build.sbt → Application build script
conf → Configurations files and other non-compiled resources (on classpath)
└ application.conf → Main configuration file
└ routes → Routes definition
public → Public assets
└ stylesheets → CSS files
└ javascripts → Javascript files
└ images → Image files
project → sbt configuration files
└ build.properties → Marker for sbt project
└ plugins.sbt → sbt plugins including the declaration for Play itself
lib → Unmanaged libraries dependencies
logs → Standard logs folder
└ application.log → Default log file
target → Generated stuff
└ scala-2.10.0
└ cache
└ classes → Compiled class files
└ classes_managed → Managed class files (templates, ...)
└ resource_managed → Managed resources (less, ...)
└ src_managed → Generated sources (templates, ...)
test → source folder for unit or functional tests

6. The conf/routes file
# Routes
# This file defines all application routes (Higher priority routes first)
# ~~~~
# Home page
GET / controllers.Application.index
# Registration page
GET /registration controllers.Application.registration
# Login page
GET /login controllers.Application.login
# logout
GET /logout controllers.Application.logout
#save userdata
POST /registration controllers.Application.createUser
# loginAuthentication
POST /login controllers.Application.loginAuthentication
# Dashboard page
GET /dashboard controllers.Application.dashboard
# Map static resources from the /public folder to the /assets URL path
GET /assets/*file controllers.Assets.at(path="/public", file)

7. The conf/application file

Configure database access

mongodb.servers=[“localhost:27017”]

mongodb.db=”test”

Logger

Router

Specific modules

8. Designing a domain models
package models
import java.util.Date
object Domains {
/*
* Case class for UserForm
*/
case class UserForm(name:String,email:String,password:
(String,String),joinDate: Date)
/*
* Case class for LoginForm
*/
case class LoginForm(email:String,password: String)
}

9. Designing a QueryBuilder models
package models
import play.api._
import play.api.mvc._
import play.api.libs.functional.syntax._
import play.api.libs.json._
import play.api.libs.concurrent.Execution.Implicits.defaultContext
import scala.concurrent.Future
import reactivemongo.api._
import play.modules.reactivemongo.MongoController
import play.modules.reactivemongo.json.collection.JSONCollection
object QueryBuilder extends Controller with MongoController {
/*
* Get a JSONCollection (a Collection implementation that is designed to work
* with JsObject, Reads and Writes.)
* Note that the `collection` is not a `val`, but a `def`. We do _not_ store
* the collection reference to avoid potential problems in development with
* Play hot-reloading.
*/
def collection(collectionname: String): JSONCollection =
db.collection[JSONCollection](collectionname)

10. Cont...
def getDocumentsByQuery(collectionname: String, query: JsObject):
Future[List[JsObject]] = {
val cursor: Cursor[JsObject] =
collection(collectionname).find(query).cursor[JsObject]
val futureresult: Future[List[JsObject]] = cursor.collect[List]()
futureresult
}
def insertDocuments(collectionname: String, documents: JsObject) {
collection(collectionname).insert(documents)
}
}

11. Designing a helper class
package utils
import play.api.mvc.RequestHeader
object Helper {
/*
* find URI
* @param request
*/
def findUri(request: RequestHeader): String = {
request.uri
}

12. Cont...
/*
* find session values
* @param request
* @param element - find session value stored in element
*/
def findSession(request: RequestHeader, element: String): String = {
request.session.get(element).map { sessionvalue =>
sessionvalue
}.getOrElse {
" "
}
}

13. Cont...
/*
* find flash values
* @param request - HTTP request
* @param element - find flash value stored in element
*/
def findFlash(request: RequestHeader, element: String): String = {
request.flash.get(element).getOrElse {
" "
}
}
}

14. Designing a constants class
package utils
object Constants {
val USER_COLLECTION_NAME = "user"
val MIN_LENGTH_OF_PASSWORD = 6
val PASSWORD_NOT_MATCHED = "Password must be matched"
val HOME_PAGE_TITLE = "Welcome to home page"
val WRONG_LOGIN_DETAILS = "The email or password you entered is incorrect"
val DASHBOARD_TITLE = "Welcome to dashboard"
val ENTERED_EMAIL_EXISTS = "Entered email id already exist in database"
val DEFAULT_PROFILE_IMAGE = "profile.jpeg"
}

15. Calling business logic (Controller)
package controllers
import models.Domains._
import models.QueryBuilder._
import utils.Helper._
import utils.Constants._
import play.api._
import play.api.mvc._
import play.api.data.Form
import play.api.data.Forms._
import play.api.libs.concurrent.Execution.Implicits.defaultContext
import play.api.libs.functional.syntax._
import play.api.libs.json._
import java.util.Date
import scala.concurrent.Future
import views.html
object Application extends Controller {

16. Cont...
/*
* userForm
*/
val userForm = Form(
mapping(
"name" -> nonEmptyText, "email" -> email, "password" -> tuple("main" ->
nonEmptyText(MIN_LENGTH_OF_PASSWORD), "confirm" -> nonEmptyText).
verifying(PASSWORD_NOT_MATCHED, passwords => passwords._1 ==
passwords._2), "joinDate" -> date("yyyy-MM-dd"))(UserForm.apply)
(UserForm.unapply))
/*
* Login Form
*/
val loginForm = Form(
mapping(
"email" -> email,
"password" -> nonEmptyText)(LoginForm.apply)(LoginForm.unapply))

17. Cont.....
/*
* Redirect Home Page
*/
def index = Action { request =>
Ok(html.index(HOME_PAGE_TITLE, findUri(request)))
}
/*
* Redirect Registration Page
*/
def registration = Action { implicit request =>
val name = findFlash(request, "name")
val email = findFlash(request, "email")
if (email != " ") {
val userForm = Application.userForm.fill(UserForm(name, email, (" ", "
"), new Date))
}
Ok(html.registration(userForm, findUri(request)))
}

18. Cont...
/*
* Redirect Login Page
*/
def login = Action { implicit request =>
val email = findFlash(request, "email")
if (email != " ") {
val loginForm = Application.loginForm.fill(LoginForm(email, " "))
}
Ok(html.login(loginForm, findUri(request)))
}
/*
* Logout and clean the session.
*/
def logout = Action { implicit request =>
Redirect(routes.Application.login).withNewSession
}

19. Cont...
/*
* Handle UserForm Submission
*/
def createUser = Action.async { implicit request =>
userForm.bindFromRequest.fold(
error => Future(BadRequest(html.registration(error, findUri(request)))),
userForm => {
val name = userForm.name
val email = userForm.email
val (password, _) = userForm.password
val joinDate = userForm.joinDate
val saveRecord = Json.obj("name" -> name, "email" -> email, "password" -> password,
"joinDate" -> joinDate)
val jsonuserdata = Json.obj("email" -> email)
val futureUserdetails = getDocumentsByQuery(USER_COLLECTION_NAME, jsonuserdata)
futureUserdetails.map { result =>
if (result.size > 0) {
Redirect(routes.Application.registration).flashing(
"message" -> ENTERED_EMAIL_EXISTS, "name" -> name, "email" -> email)
} else {
val futuresaveUser = insertDocuments(USER_COLLECTION_NAME, saveRecord)
Redirect(routes.Application.dashboard).withSession(
"email" -> email)
}
}
})
}

20. Cont...
/*
* Login Authentication
*/
def loginAuthentication = Action.async { implicit request =>
loginForm.bindFromRequest.fold(
error => Future(BadRequest(html.login(error, findUri(request)))),
loginForm => {
val email = loginForm.email
val password = loginForm.password
val jsonuserdata = Json.obj("email" -> email, "password" -> password)
val futureUserdetails = getDocumentsByQuery(USER_COLLECTION_NAME,
jsonuserdata)
futureUserdetails.map { result =>
if (result.size > 0) {
Redirect(routes.Application.dashboard).withSession(
"email" -> email)
} else {
Redirect(routes.Application.login).flashing(
"message" -> WRONG_LOGIN_DETAILS, "email" -> email)
}
}
})
}

21. Cont...
/*
* Redirect Dashboard
*/
def dashboard = Action.async { implicit request =>
if (findSession(request, "email") == " ") {
Future(Redirect(routes.Application.login))
} else {
val jsonuserdata = Json.obj("email" -> findSession(request, "email"))
val userfutureresult = getDocumentsByQuery(USER_COLLECTION_NAME,
jsonuserdata)
userfutureresult.map { result =>
Ok(html.dashboard(DASHBOARD_TITLE, findUri(request),result))
}
}
}
}

22. The templating system
(main.scala.html)
@(title:String)(content:Html)
<!DOCTYPE html>
<html lang="en">
<head>
<title>@title</title>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" media="screen"
href="@routes.Assets.at("Bootstrap/css/bootstrap.min.css")">
<link rel="stylesheet" media="screen"
href="@routes.Assets.at("Bootstrap/css/bootstrap-theme.min.css")">
<link rel="stylesheet" media="screen"
href="@routes.Assets.at("css/custom.css")">
<script src="@routes.Assets.at("jquery/jquery-1.11.1.min.js")"
type="text/javascript"></script>
<script src="@routes.Assets.at("Bootstrap/js/bootstrap.min.js")"
type="text/javascript"></script>
<script src="@routes.Assets.at("Bootstrap/js/bootstrap.js")"
type="text/javascript"></script>
</head>
<body>@content
</body>
</html>

23. Cont...
registration.scala.html
@import models.Domains._
@(userForm:Form[UserForm],path:String)(implicit flash: Flash)
@import helper._
@main("Welcome to Registration Page"){
<div class="container">
@header(path)
<div class="jumbotron">
@form(routes.Application.createUser){
@registrationformElements(userForm)
<div class="registration-error">@flash.get("message")</div>
<input type="submit" name="submit" value="Submit" class="btn btn-primary">
}
</div>
@footer()
</div>
}

24. Cont...
registrationformElements.scala.html
@import models.Domains._
@(userForm: Form[UserForm])
@import helper._
@implicitField = @{ helper.FieldConstructor(BootstrapInput.f) }
@inputText(userForm("name"),'_label -> "Name", '_showConstraints -> false,'class
-> "form-control")
@inputText(userForm("email"),'_label -> "Email", '_showConstraints ->
false,'class -> "form-control")
@inputPassword(userForm("password.main"),'_label -> "Password", '_help
->"Password should be minimum 6 character",'class -> "form-control")
@inputPassword(userForm("password.confirm"),'_error
->userForm.error("password"), '_label -> "Confirm Password", '_showConstraints
-> false,'class -> "form-control")
@inputText(userForm("joinDate"),'_label -> "Joining Date", '_showConstraints ->
false,'class -> "form-control")

25. Questions ?

26. THANK YOU