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pythongoogle-app-enginedatastoreexpandodynamic-variables

How to create dynamic fields in Google App Engine expando class?

I have a db expando class called widget.

I'm passing in a json string and converting it to a dict and then adding it to the datastore.

My question is how can I loop through my dict to create dynamic fields.

widget = Widget.get_by_key_name(key_name)
widget.name = self.request.get('wname')
fields = simplejson.loads(self.request.get('wcontents'))
for k,v in fields.iteritems():
  widget.k = v

This renders "k" as my field name as oppose to the k value in the dict.

Solution

  • The syntax widget.k references the attribute k on object widget. To dynamically choose which attribute you set, use the built-in setattr method:

    setattr(widget, k, v)

    Dynamically setting an attribute like this will create the field on that particular entity.