Java Reference
In-Depth Information
C H A P T E R 8
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App Engine Services
In Chapter 7 you spent a lot of time in the data layer of the application stack. Let's
take it up one level and focus on some of the functional services available to App
Engine applications. The App Engine JRE has APIs for App Engine services that
include a memory cache service, an HTTP request service, a mail API, an image
API, and the Google Accounts API, which we discussed in Chapter 6. And, new to
version 1.2.5, is the XMPP service, which allows your App Engine application to
interact with XMPP-based applications like Google Talk.
This chapter starts with a quick review of the Memcache service, the URL
Fetch service, and the Images service. We'll go a little deeper with some functional
examples of the Mail API and the XMPP service. You'll be creating an application
that sends an e-mail via the Mail API and also sends an instant message via XMPP.
Setting up the Project
Throughout this chapter you'll be using a single project for all the examples. To
get that project started, create a new web application project in Eclipse. Call the
project GAEJ - AppEngine Services. Make sure you uncheck Google Web Toolkit in
the New Web Application Project dialog. Figure 8-1 shows the project settings I'll
be using in the examples in this chapter.
