Appengine: Transaction Safe Reference Properties with Ancestor Queries

This is a quick article on transactions with “one to many” relationship queries within a single by utilizing entity groups and ancestor queries. If you find it helpful, please feel free to link to it and help spread the google juice. Special thanks to co-worker Robert Kluin for helping me figure this out last week. My Problem My initial problem was that I was working inside a...

Appengine: getCurrentUser() is None but app.yaml login:admin Allows Access?

Today, while working on Google AppEngine code, I discovered a bug in AppEngine, but it just turned out to be a typo. I spent a good few hours googling before tearing things apart and solving the tricky issue. As such, I am sharing my finds to help others’ save some time and stress. Short version is to check your regular expressions in the app.yaml file when adding security to an entire...

Appengine Django/GQL – Ensuring Uniqueness of Model Type on Edit – Not Equals Filters

Edit 2009-02-02 - Added note about inequality query complexity. Spoiler – inequalities are 2 queries under the hood. In my further adventures in Google AppEngine land, I wanted to ensure uniqueness of an email field while still allowing the user to change their email address. Since, Google App Engine’s BigTable doesn’t allow you to custom define unique indexes, this poses a...