app-engine-ndb

I would like to confirm my understanding of eventual consistency in the Google datastore. Suppose that I have an entity defined as follows (using ndb): class Record(ndb.Model): name = ndb.StringProperty() content = ndb.BlobProperty() I think I understand Scenarios 1, but I have doubts about Scenarios 2 and 3, so some advice would be highly appreciated. Scenario 1: I insert a new Record with name "Luca" and a given content. Then, I query the datastore: qry = Record.query(name=="Luca") for r in qry.iter(): logger.info("I got this content: %r" % r.content) I understand that, due to eventual

The following code works as expected and does not trigger the assertion: @ndb.transactional @ndb.tasklet def Foo(): assert ndb.in_transaction() The following code breaks, triggering the assertion: @ndb.transactional @ndb.toplevel def Foo(): assert ndb.in_transaction() I tried replacing the decorator with an ndb.transaction call or an ndb.transaction_async call, but neither worked. Is there a bug with ndb.toplevel and transactions? I discovered that the problems is that both create new contexts. transactional creates a context and ensures that all writes that happen inside of it are non

My question is very fundamental, I want to know straight forward and right way to access attribute values of parent entity from a child in App Engine Python. For example I have following model schema. I am using Python 2.7 and NDB. class Gallery(ndb.Model): category = ndb.StringProperty() title = ndb.StringProperty() subtitle = ndb.StringProperty() class Image(ndb.Model): blob_key = ndb.BlobKeyProperty() title = ndb.StringProperty() gallery = ndb.StringProperty() is_slider = ndb.StringProperty() Here "Gallery" is parent of "Image". They form an entity group Exhibition=>Gallery=>Image. I want

ReferenceProperty was very helpful in handling references between two modules. Fox example: class UserProf(db.Model): name = db.StringProperty(required=True) class Team(db.Model): manager_name = db.ReferenceProperty(UserProf, collection_name='teams') name = db.StringProperty(required=True) To get 'manager_name' with team instance, we use team_ins.manager_name. To get 'teams' which are managed by particular user instance, we use user_instance.teams and iterate over. Doesn't it look easy and understandable? In doing same thing using NDB, we have to modify db.ReferenceProperty(UserProf,

I want the user to be able to upload images to Google App Engine. I have the following (Python): class ImageData(ndb.Model): name = ndb.StringProperty(indexed=False) image = ndb.BlobProperty() Information is submitted by the user using a form (HTML): <form name = "input" action = "/register" method = "post"> name: <input type = "text" name = "name"> image: <input type = "file" name = "image"> </form> Which is then processed by: class AddProduct(webapp2.RequestHandler): def post(self): imagedata = ImageData(parent=image_key(image_name)) imagedata.name = self.request.get('name') imagedata.image

I am completely novice at AJAX. I am familiar with HTML/CSS, jQuery and beginner at GAE and Python. In an effort to understand how AJAX works, I would like to know how AJAX might be used (actual code) in this example below. Let's use a reddit-like example where vote ups/downs are ajaxified: Here is the Story Kind: class Story(ndb.Model): title = ndb.StringProperty(required = True) vote_count = ndb.IntegerProperty(default = 0) The HTML would look like this: <h2>{{story.title}}</h2> <div> {{story.vote_count}} | <a href="#">Vote Up Story</a> </div> How does AJAX fit inside here? Ok Sir here we go