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The easiest way to get setup rapidly is to download the template project from the download section. It provides a ready-to-go project with the right configuration files pre-filled and an appropriate directory layout: web.xml preconfigured with the Gaelyk servlets appengine-web.xml with the right settings predefined (static file directive) a sample Groovlet and template the needed JARs (Groovy, Gaelyk and Google App Engine SDK)

Running your application locally Google App Engine provides a local servlet container, powered by Jetty, which lets you run your applications locally. If you're using the Gaelyk template, when you're at the root of your project — and we assume you have installed the App Engine SDK on your machine — you can run your application with the following command-line: dev_appserver.sh war

Deploying your application in the cloud Once you're at the root of your application, simply run the usual deployment command: appcfg.sh update war

you can use the sample project that the google plugin for eclipse create for you. Then you can easily replace the generated java code by groovy / gaelyk code. Note that you need to add the jars in the war/WEB-INF/lib of your project, and add them in the project build path options.

You can study the JavaMail API in more detail to understand how to do things like sending attachments in your email too. You can do that using the Google App Engine Email Service.

Queries involving keys use indexes just like queries involving properties. Queries on keys require custom indexes in the same cases as with properties, with a couple of exceptions: inequality filters or an ascending sort order on __key__ do not require a custom index, but a descending sort order on __key__ does. As with all queries, the development web server creates appropriate configuration entries in this file when a query that needs a custom index is tested.

3. Adds a new gae:start goal. This is identical to gae:run, except that it does not automatically execute the package phase before starting the server. The intent is to use this in a project POM, but it can also be used to start the server quickly when you don't want to rebuild the project. Right now I just copied the RunGoal completely, except for the '@execute phase="package"' declaration, because I didn't want to introduce conflicts in case someone else is editing RunGoal.java. A better thing to do in the future would be to have RunGoal extend StartGoal with an empty class that just adds the '@execute phase="package"' annotation (it can't be the other way around, with StartGoal extending Run goal, because there's no way to override a mojo with an @execute annotation with one that doesn't have it---it gets inherited automatically).

The idea behind all of these changes is to make it so that you can use the maven-gae-plugin in a project's POM for automated integration tests. The gae:start goal automatically binds to the pre-integration-test phase by default, and the gae:stop goal binds to post-integration-test. This is most useful when combined with something like the maven-failsafe-plugin and a functional testing library like HtmlUnit that you can use to simulate web requests. It would also be useful for Selenium testing.

build-time substitution. Here’s our appengine-web.xml: <?xml version="1.0" encoding="utf-8"?> <appengine-web-app xmlns="http://appengine.google.com/ns/1.0"> <application>${gae.app.name}</application> <version>${friendlyversion}</version> <system-properties> <property name="java.util.logging.config.file" value="WEB-INF/logging.properties"/> </system-properties> </appengine-web-app>

At build time, I use the AntRun plugin (lines 97-118) to create a small file under the target directory that holds a ‘sanitized’ version of the standard Maven version. (I.e. “1.0-SNAPSHOT” becomes GAE-friendly “1-0-snapshot”.) I then use the Maven filter functionality available in the WAR plugin (lines 80-96) to copy the appengine-web.xml into its proper directory with the version substituted in.

This tutorial concerns using Google Accounts to maintain the existence of your users in a Google App Engine application. Google App Engine provides the class UserServiceFactory to facilitate that. UserServiceFactory is then used to generate UserService object, which in turn provides the following features createLoginURL createLogoutURL getCurrentUser isUserAdmin isUserLoggedIn You would use UserService object to generate the login URL for the browser. The browser would be directed/redirected to this URL. On reaching this URL, the Google log-in prompt would be displayed by Google's server.

to write a string to a twitter account. Here’s my original java code:

This article studies the proxy technique first and then turns to the Google AJAX Feed API method, giving you a chance to intermix Java™and JavaScript coding.

You need a service that, when given a feed URL, connects to that site, downloads its contents, and sends them back to the caller. (For a shell-line parallel, consider the wget or curl command.) You can do this many ways, and Listing 2 shows a simple way to accomplish the task. Because I decided to call my remote proxy RemoteProxy, the server-side class had to be called RemoteProxyImpl; Impl stands for "Implementation."

The SOP won't let your code get data from another site, but there's an exception: You can download and execute JavaScript code using the <script ... /> tag. If the code you download happens to include data and calls a function of yours that puts the data to good use, then you have managed to bypass the SOP. Here's the idea behind the Google AJAX Feed API: It uses the <script ... /> tag to call a Google site that works as a proxy. The remote site gets the feed data and returns it in the form of JavaScript code. The downloaded JavaScript code calls your function so you can process the incoming XML