This document provides an overview of the Play! web framework, including its architecture, standard project layout, routing configuration, templating system, and an example of how to build a user registration and login application with Play!. Key points include that Play! is a stateless framework that integrates with JSON and provides a full stack web development environment with built-in features, compilation and error checking. The document outlines how to set up a Play! project and its standard directory structure, configure routes and application settings, design domain models, queries and helper classes, and call business logic from controllers using templated views.

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

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