Store dict in AppEngine Datastore

This post is about Python and Google Appengine.

I want to store a dict/dictionary in a model. There is no native DictProperty. However there are workarounds.

• Encode it somehow (for example with pickle) and store it as a blob.
• Use an Expando model and store your key-values with setattr(yourmodel, key, value). You can get your dict later with yourmodel.dynamic_properties(). See also delattr. This seems to trigger encoding bugs for non-ascii keys.
• Store keys and values separately with two StringListProperty. Combine them to build a dict with dict(zip(keylist, valuelist)).