Add AppEngine ModelViews for both DB and NDB. Tested it works on flask_admin...

Add AppEngine ModelViews for both DB and NDB. Tested it works on flask_admin running on my local dev_appserver, and works much better than the built-in appengine admin site. More complex features still remain TBD (queries, as well as nested keys, and probably other obscure features)

flask_admin/contrib/appengine/__init__.py

+try:
+    import wtforms_appengine
+except ImportError:
+    raise Exception('Please install wtforms_appengine in order to use appengine backend')
+
+from .view import ModelView

flask_admin/contrib/appengine/view.py

+import logging
+
+from flask.ext.admin.model import BaseModelView
+from wtforms_appengine import db as wt_db
+from wtforms_appengine import ndb as wt_ndb
+
+from google.appengine.ext import db
+from google.appengine.ext import ndb
+
+class NdbModelView(BaseModelView):
+	"""
+	AppEngine NDB model scaffolding.
+	"""
+
+	def get_pk_value(self, model):
+		return model.key.urlsafe()
+
+	def scaffold_list_columns(self):
+		return [k for (k, v) in self.model.__dict__.iteritems() if isinstance(v, ndb.Property)]
+
+	def scaffold_sortable_columns(self):
+		return [k for (k, v) in self.model.__dict__.iteritems() if isinstance(v, ndb.Property) and v._indexed]
+
+	def init_search(self):
+		return None
+
+	def is_valid_filter(self):
+		pass
+
+	def scaffold_filters(self):
+		#TODO: implement
+		pass
+
+	def scaffold_form(self):
+		return wt_ndb.model_form(self.model())
+
+	def get_list(self, page, sort_field, sort_desc, search, filters):
+		#TODO: implement filters (don't think search can work here)
+
+		q = self.model.query()
+
+		if sort_field:
+			order_field = getattr(self.model, sort_field)
+			if sort_desc:
+				order_field = -order_field
+			q = q.order(order_field)
+
+		results = q.fetch(self.page_size, offset=page*self.page_size)
+		return q.count(), results
+
+	def get_one(self, urlsafe_key):
+		return ndb.Key(urlsafe=urlsafe_key).get()
+
+	def create_model(self, form):
+		try:
+			model = self.model()
+			form.populate_obj(model)
+			model.put()
+			return True
+		except Exception as ex:
+			if not self.handle_view_exception(ex):
+				#flash(gettext('Failed to create record. %(error)s',
+				#	error=ex), 'error')
+				logging.exception('Failed to create record.')
+			return False
+
+	def update_model(self, form, model):
+		try:
+			form.populate_obj(model)
+			model.put()
+			return True
+		except Exception as ex:
+			if not self.handle_view_exception(ex):
+				#flash(gettext('Failed to update record. %(error)s',
+				#	error=ex), 'error')
+				logging.exception('Failed to update record.')
+			return False
+
+	def delete_model(self,  model):
+		try:
+			model.key.delete()
+			return True
+		except Exception as ex:
+			if not self.handle_view_exception(ex):
+				#flash(gettext('Failed to delete record. %(error)s',
+				#	error=ex),
+				#	'error')
+				logging.exception('Failed to delete record.')
+		return False
+
+
+class DbModelView(BaseModelView):
+	"""
+	AppEngine DB model scaffolding.
+	"""
+
+	def get_pk_value(self, model):
+		return str(model.key())
+
+	def scaffold_list_columns(self):
+		return [k for (k, v) in self.model.__dict__.iteritems() if isinstance(v, db.Property)]
+
+	def scaffold_sortable_columns(self):
+		return [k for (k, v) in self.model.__dict__.iteritems() if isinstance(v, db.Property) and v._indexed]
+
+	def init_search(self):
+		return None
+
+	def is_valid_filter(self):
+		pass
+
+	def scaffold_filters(self):
+		#TODO: implement
+		pass
+
+	def scaffold_form(self):
+		return wt_db.model_form(self.model())
+
+	def get_list(self, page, sort_field, sort_desc, search, filters):
+		#TODO: implement filters (don't think search can work here)
+
+		q = self.model.all()
+
+		if sort_field:
+			if sort_desc:
+				sort_field = "-" + sort_field
+			q.order(sort_field)
+
+		results = q.fetch(self.page_size, offset=page*self.page_size)
+		return q.count(), results
+
+	def get_one(self, encoded_key):
+		return db.get(db.Key(encoded=encoded_key))
+
+	def create_model(self, form):
+		try:
+			model = self.model()
+			form.populate_obj(model)
+			model.put()
+			return True
+		except Exception as ex:
+			if not self.handle_view_exception(ex):
+				#flash(gettext('Failed to create record. %(error)s',
+				#	error=ex), 'error')
+				logging.exception('Failed to create record.')
+			return False
+
+	def update_model(self, form, model):
+		try:
+			form.populate_obj(model)
+			model.put()
+			return True
+		except Exception as ex:
+			if not self.handle_view_exception(ex):
+				#flash(gettext('Failed to update record. %(error)s',
+				#	error=ex), 'error')
+				logging.exception('Failed to update record.')
+			return False
+
+	def delete_model(self,  model):
+		try:
+			model.delete()
+			return True
+		except Exception as ex:
+			if not self.handle_view_exception(ex):
+				#flash(gettext('Failed to delete record. %(error)s',
+				#	error=ex),
+				#	'error')
+				logging.exception('Failed to delete record.')
+		return False
+
+def ModelView(model):
+	if issubclass(model, ndb.Model):
+		return NdbModelView(model)
+	elif issubclass(model, db.Model):
+		return DbModelView(model)
+	else:
+		raise ValueError("Unsupported model: %s" % model)
+