Play Framework Essentials

Julien Richard-Foy

• Publisher: Packt Publishing
• Year: 2014
• ISBN:
  9781783982400
• Edition: 1
• Topic: Computer Science
• Subtopic: Web Development
• Index: Computer Science

Play is a framework to write web applications using Scala or Java. It provides a productive development environment, allowing you to just hit the "refresh" button in your browser to compile your changes and reload the application. Because of its stateless nature, the framework makes it easy to build applications that scale. Play provides a reactive programming model to harness the event-driven HTTP layer.

This book provides a step-by-step walkthrough of how to build a complete web application following best application development practices using Play framework 2. All aspects specific to web-oriented architectures are covered: the HTTP layer, JSON manipulation, HTML templating, asset compression and concatenation, form submission, content negotiation, security, and HTTP streaming. The book will also provide detailed architectural insights into Play framework to give you a better understanding in order to successfully build scalable applications.

Play Framework Essentials

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Table of Contents

Play Framework Essentials

Credits

About the Author

About the Reviewers

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Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Building a Web Service

Play – a framework used to write web applications

Bootstrapping a Play application

Play applications' layout

URL routing

Route path parameters

Parameters type coercion

Parameters with fixed values

Query string parameters

Default values of query string parameters

Trying the routes

Building HTTP responses

Serializing application data in JSON

Reading JSON requests

Validating JSON data

Handling optional values and recursive types

Summary

2. Persisting Data and Testing

Testing your web service

Writing and running tests

Testing the HTTP layer

Using the reverse router to generate URLs

Running a fake Play application

Effectively writing HTTP tests

Persisting data

Using a relational database

Getting a reference to the currently running application

Using a database management library

Using Slick in Scala

Using JPA in Java

Integrating with other persistence technologies

Populating the database with fixtures

The application's Global object

Managing database schema evolutions

Using an in-memory database for tests

Summary

3. Turning a Web Service into a Web Application

Delta between a web service and a web application

Using the template engine to build web pages

Inserting dynamic values

Looping and branching

Reusing document fragments

Comments

Import statements

Generating HTML forms

Repeated and nested fields

Reading and validating HTML form data

Handling the HTML form submission

Validating the HTML form data

The Scala form validation API

The Java form validation API

Optional and mandatory fields

Sharing JSON validation and HTML form validation rules

Handling content negotiation

Putting things together

Writing web user interface tests

Summary

4. Integrating with Client-side Technologies

Philosophy of Play regarding client-side technologies

Serving static assets

Sprinkling some JavaScript and CSS

Using the JavaScript reverse router

Managing assets from the build system

Producing web assets

Pipelining web assets' transformations

Concatenating and minifying JavaScript files

Gzipping assets

Fingerprinting assets

Managing JavaScript dependencies

Running JavaScript tests

Summary

5. Reactively Handling Long-running Requests

Play application's execution model

Scaling up your server

Embracing non-blocking APIs

Managing execution contexts

Writing incremental computations using iteratees

Streaming results using enumerators

Manipulating data streams by combining iteratees, enumerators, and enumeratees

Unidirectional streaming with server-sent events

Preparing the ground

Transforming streams of data using enumeratees

Implementing a publish/subscribe system using Akka

Bidirectional streaming with WebSockets

Controlling the data flow

Summary

6. Leveraging the Play Stack – Security, Internationalization, Cache, and the HTTP Client

Handling security concerns

Authentication

Cross-site scripting

Cross-site request forgery

HTTP request filters

Using the CSRF filter

Enabling HTTPS

Saving computation time using cache

Serving content in several languages

Calling remote web services

Background – the OAuth 2.0 protocol

Integrating your application with your preferred social network

Implementing the OAuth client

Calling the HTTP API of your preferred social network

Summary

7. Scaling Your Codebase and Deploying Your Application

Making an action's logic reusable and composable with action builders

Capturing the logic of actions that use blocking APIs

Capturing the logic of actions that require authentication

Combining action builders

Modularizing your code

Applying the inversion of control principle

Using dynamic calls in route definitions

Setting up a dependency injection system

Making your code injectable

Mocking components

Splitting your code into several artifacts

Splitting your controller layer into several artifacts

Application deployment

Deploying to your dedicated infrastructure

Deploying to the cloud

Handling per environment configuration

Overriding configuration settings using Java system properties

Using different configuration files

Summary

Index

Play Framework Essentials

Copyright © 2014 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: September 2014

Production reference: 1190914

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-78398-240-0

www.packtpub.com

Cover image by Pratyush Mohanta (<[email protected]>)

Credits

Author

Julien Richard-Foy

Reviewers

Shannon –jj Behrens

Cédric Chantepie

Commissioning Editor

Amarabha Banerjee

Acquisition Editor

Vinay Argekar

Content Development Editor

Akashdeep Kundu

Technical Editors

Indrajit A. Das

Taabish Khan

Humera Shaikh

Copy Editors

Deepa Nambiar

Laxmi Subramanian

Project Coordinator

Kartik Vedam

Proofreaders

Simran Bhogal

Maria Gould

Ameesha Green

Paul Hindle

Indexers

Monica Ajmera Mehta

Tejal Soni

Graphics

Abhinash Sahu

Production Coordinators

Aparna Bhagat

Manu Joseph

Cover Work

Aparna Bhagat

About the Author

Julien Richard-Foy likes to design code that seamlessly expresses the ideas he has in mind. He likes finding the right level of abstraction, separating concerns, or whatever else that makes the code easy to reason about, to maintain and to grow.

He works at Zengularity, the company that created the Play framework, and actively contributes to the evolution of the framework.

He aims at working on technically challenging and innovative projects that have a positive envir...

Table of contents

• Play Framework Essentials