Book Image

Play Framework Essentials

By : Julien Richard-Foy
Book Image

Play Framework Essentials

By: Julien Richard-Foy

Overview of this book

Table of Contents (14 chapters)
Play Framework Essentials
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Calling remote web services


Web applications sometimes make use of an external web service. For this purpose, Play provides an HTTP client. To use it, add the following dependency to your build:

libraryDependencies += ws

In Java, the library is named javaWS:

libraryDependencies += javaWs

Background – the OAuth 2.0 protocol

Though some web services can be freely used, most of them provide only authenticated APIs. The OAuth 2.0 protocol is often used as an authentication system. You can find more about OAuth at http://oauth.net/2/. Incidentally, authenticating using OAuth requires calling a web service (the authorization server as depicted in the following figure), so we will implement an OAuth client to illustrate how to call web services:

As a reminder, the preceding figure shows a typical workflow using OAuth. In this scenario, the user performs some action that requires the application to get a resource held by an external resource server, on behalf of the user. The application starts by redirecting...