This document provides an overview of the Play 2 framework, including: - Play features such as type-safety and async programming. - The anatomy of a Play application including directories for assets, controllers, models, and views. - Play's MVC architecture with models, views rendered by Twirl templates, and controllers handling requests and responses. - Form handling in Play using binding and validation.

1. An Introduction to Play 2
Framework

2. Who am I?
● João Ferreira (@jtjeferreira)
● 5 years professional experience in backend
& frontend development with Java, C# and
Javascript
● Currently working @ E.Near, developing a
scala applications

3. Outline
● Play framework features
● Play application anatomy
● Play MVC
● Form handling

4. What this presentation is NOT about
● Scala introduction
● How to bootstrap a Play Application
● How to use Play for Java

5. State of Java Web Frameworks
Map[String,Object]

6. Play Features
● Type-safety
● Short feedback cycles
● Async programming

7. Play application anatomy
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
test → source folder for unit or functional tests

8. Play MVC
● Model: scala classes
● View: twirl templates
● Controllers: route file + action generator
methods

9. Play MVC - Controllers
● Controller
○ has Action generating methods
● Action (Request =>Result)
○ handles a request and generates a result

10. Play MVC - Controllers
val ok = Ok("Hello world!")
val notFound = NotFound
val pageNotFound = NotFound(<h1>Page not found</h1>)
val badRequest = BadRequest(views.html.form(formWithErrors))
val oops = InternalServerError("Oops")
val anyStatus = Status(488)("Strange response type")

11. Play MVC - Controllers
● Route file
● Reverse Routing

12. Play MVC - Views
● Uses a scala-based language (Twirl) for the
template language
● Templates are compiled to scala functions

13. Play MVC - Views
● Templates being simple functions gives us:
○ “taglibs”
○ “master templates”

14. Forms support- login use case
Login Form
userLoginForm: Form[UserLogin]
user: text
pass: text
POST /login
user=a
pass=b
Do stuff and replyLogin Success
userLogin:UserLogin
user: a
pass: b
userLoginForm.bindFromRequest
userLoginForm.fold( errorFunc, successFunc )
login.scala.html
loginSuccess.scala.html

15. The END