Google App Engine Experiments

For a while I’ve been complaining about the fact that sites such as AppAnnie and AppFigures don’t send daily summary emails of not just your apps, but the top apps in the App Store. I want to know what’s trending and topping the charts every day.

I could have made something in PHP to do this in a matter of hours, but I like to use side projects to learn something new. As an excuse to learn Google App Engine I built UpTopR: a site that emails a daily summary of the top 10 apps for iOS and iPad. It’s slow and ugly, but does what I need it to.

I used the Java API since I couldn’t find a way to deploy Python projects to GAE as easily as the Google plug-in for Eclipse does. I only had to learn how to use Google’s NoSQL App Engine Datastore and caching APIs. Otherwise, getting up and running on GAE is as easy, if not easier, than deploying a servlet on Tomcat. The whole process of learning GAE and finishing the app took about 4 days.

I’m big on PaaS now. Writing an application that magically scales inside Google’s environment is much easier than managing a cluster of EC2 instances as virtual infrastructure. Of course, writing a giant scaling servlet isn’t appropriate for a lot of tasks–but for the back-end of an asynchronous mobile game it makes a lot of sense.

Although last year’s pricing changes caused a revolt with long time GAE users, low traffic applications fall under the free usage quotas. Noodling around on GAE costs you nothing. This is great for prototyping.

Unfortunately, Google App Engine doesn’t work in China. The vast majority of IAPs in China are fraudulent, but China is kind of a big deal. Also, as useful as Google’s Datastore is, it still can’t search using geolocation without some suspect hacks. Amazon Web Services is available in China, and I can attach any kind of database I want to Amazon’s GAE equivalent, Beanstalk. This includes the geohash-supporting MongoDB. For these reasons I’m most likely going to use Amazon’s Beanstalk as a GAE alternative on future projects.

PROTIP: I had this problem for a while when trying to use as the domain for the app. Here’s what you have to know about using custom domains for GAE apps:

  • Only domain aliases for your main domain your App Engine Account is hosted on can be used with Google App Engine apps.

  • For mysterious reasons, naked domains can’t be used. You have to use a subdomain such as and use a URL redirect to point the naked domain at the subdomain.

  • Once your domain alias is registered with Google Apps, you have to type in the main active domain the alias is for on the Domain settings page for the GAE app. Then it will direct you to your Google Apps administration panel where you will be able select the alias from a dropdown.

I wish I knew this earlier! It took a few days of banging my head against a wall to figure out how to host my App Engine app on a custom domain.