I'm trying to write appengine python code that uses the built-in authentication 'users' object and using userid as an ndb key
Here's my model:
class UserAccounts(ndb.Model):
UserID = ndb.KeyProperty(required=True)
In my handler:
I get the current user
user = users.get_current_user()
Instantiate an entry
account = Models.UserAccounts()
Set the userid to the ndb entry
account.UserID = userid
When I run it, I get this:
Expected Key, got '113804764227149124198'
Where am I going wrong? As much as possible, I'd like to use a KeyProperty instead of StringProperty for performance reasons.
by:
account.UserID = userid
I assume you meant:
account.UserID = user.user_id()
The user id is a string, not a key, so you can't use a KeyProperty here. In fact, AFAIK, User objects as returned from users.get_current_user() don't have a key (at least not one that is documented) since they aren't datastore entries. There is an ndb.UserProperty, but I don't think it's use is generally encouraged.
What performance reasons are you referring to?
I think what you want is something like this UserAccounts(id=user_id), this way the user_id is the key. With this approach you can remove the userid field from the model definition
Related
I have the following models:
class Company(ndb.Model):
name = ndb.StringProperty(indexed=False)
# some other fields
class User(polymodel.PolyModel):
company = ndb.KeyProperty(kind=Company)
# some other fields
class Object(ndb.Model):
user = ndb.KeyProperty(kind=User)
# some other fields
Now I have a user and I want to query Objects that are associated with other Users in the same company like this:
Object.query(Object.user.company == user.company)
Of course, this doesn't work, since Object.user is a key and I cannot access anything beyond that.
Is there any way to do it? I only need the company key, I was thinking on a ComputedProperty but I'm not sure if it's the best solution. Also, it would be better to query based on any field in company.
You need to denormalize and store redundant information, as the datastore doesn't support joins.
For instance given your models above, a user can only be a member of one company, if you really need to search all objects whose user is a member of a particular company then store the company key in the Object.
Use a computed property if that works best for you.
Alternately use a factory that always takes the User as a argument and construct Object that way.
I have a ndb model and I use Python + google appengine. I want to add primary key to my first field "name". Forexample I added a name "Ada", after that if I want to add again "Ada", it mustnt add, it gives me an error. I can do it easily with django but I couldnt figure out with google appengine. Can you show me a solution way please. Here is my codes:
class User(ndb.Model):
username = ndb.StringProperty(indexed=False)
created_date = ndb.DateTimeProperty(auto_now_add=True)
updated_date = ndb.DateTimeProperty(auto_now_add=True)
You should use the get_or_insert() which will add a named key to your entity.
So if your username is name = 'Ada' you could do something like this:
user_db = User.get_or_insert(name.lower(), username=name)
The first parameter is the key_name and I used the lower() function just to make sure that they will be consistent and somebody with a name 'ADA' wouldn't be able to create a new entity, unless you want that.
I have saved the user_id() field and now I want to query the datastore for that user.
How would I go about accomplishing that?
#Something like
user = db.Query(MyUser).filter('user.user_id() = ', 1234).fetch(limit=1)
Thanks
You should create a separate string property to store the user ID, then query for that. The UserProperty class is full of traps and is best avoided.
if what you are searching for is the actual entity Id then you can query for it with the get_by_id method
user = MyUser.get_by_id(1234)
note that if you create it with a parent the you need to pass that to the get_by_id() function too.
user = MyUser.get_by_id(1234, parent=parent)
docs:
https://developers.google.com/appengine/docs/python/datastore/modelclass#Model_get_by_id
I defined a simple class in GAE for keeping user profiles data like this:
class User(db.Model):
email = db.EmailProperty()
role = db.StringProperty(default=roles.USER)
first_name = db.StringProperty()
last_name = db.StringProperty()
...
I use memcache to keep session information. memcache data looks like this { 'key': 'agpjYW5kaXJhdGVzcgoLEgRVc2VyGCMM'}. I get session_id value from the cookie. When I try to get user info linked to that cookie like this:
session_id = request['session_id']
data = memcache.get(session_id)
user = User.get(data['key'])
I get KindError exception:
KindError: Kind 'User' is not a subclass of kind 'User'
I know this user exists, memcache exists. User class is defined only once in my project. Why this error occurs and how can I make it work?
UPDATE: I tried to use db.get() instead of User.get() and it worked. So, what's the problem there can be?
Model.get() does check whether the supplied key is of the correct kind, as defined in the documentation. If not of the correct kind it will throw a KindError.
db.get() does not do any type checking and therefore will succeed with the supplied value if it exists in the data store, but will not necessarily return a User entity.
So you need to check whether the key in your memcache is actually of the User kind. Are you sure it's not overwritten with the key of a different model at some point?
The App Engine framework defines a class called 'User' as part of the Users API. In addition, you have your own class by the same name. When the exception occurs, you're trying to use one, but getting the other.
To avoid this, rename your model. You should also be careful how you import modules in Python. Instead of:
from google.appengine.api.users import User
or worse:
from google.appengine.api.users import *
you should use:
from google.appengine.api import users
And then refer to users.User, which is unambiguous.
The problem, it seems to me, is more subtle than that. I was getting the error with this call to Model.get() (I'm retrieving a top-level singleton object, always there):
datastore = GDSDatastore.get(gds.Key.from_path(*path))
so I investigated with this code:
datastore = gds.get(gds.Key.from_path(*path))
if not(datastore is None or isinstance(datastore, GDSDatastore)):
logger.error("KindError isinstance(GDSDatastore)=%s class=%s" % (isinstance(datastore, GDSDatastore), datastore.__class__.__name__))
raise gds.KindError('Kind %r is not a GDSDatastore instance' %
(datastore.kind()))
The vast majority of the time I get no error, but today I got this interesting log:
KindError isinstance(GDSDatastore)=False class=GDSDatastore
Now, that strikes me as rather peculiar.
(Note: GDSDatastore is defined locally: class GDSDatastore(gds.Model))
It seems that the default primary key is int. Is there anyway to use the big integer for the autofield as the primary key?
I would suggest you use a newer Django. Official Django documentation doesn't go farther back than 1.3 now. And 1.3 is insecure and unsupported. I realize the question was asked over 3 years ago, but since there is still no accepted answer I will give it a shot.
In Django 1.6.5 you can just do this in your model:
class MyModel(models.Model):
id = models.BigIntegerField(unique=True, primary_key=True)
The primary_key=True will override the default id on the model. In use this field auto increments with each new model object. It just works!
There are a couple of ways I can see to implement this. Either way, you have to define your pk field.
First of all, just create your own id field and override the save method.
modelname(models.Model):
# model definition
def save(self):
self.pkfield = nextIntFucntion()
super(modelname, self).save()
The nextIntFunction() is easy enough with a query of objects ordered by id, then get the id+1
I also found this link BigIntegerField and BigAutoField which seems to solve the problem, but I have not tested it myself
I met the same question too.
I have add some code like
User._meta.has_auto_field = True
User._meta.auto_field = id
And I define the id field to BigIntegerField(primary_key=True)
After I use user.Save(), user.id will have its id, don't need I query again.
I think it works, but it is not a beautiful solution, so I still finding a good way.
Since Django 1.10 you can use BigAutoField as described on documentation works exactly as AutoField but it is guaranteed to fit numbers from 1 to 9223372036854775807.
So you can use it like:
class SomeModel(models.Model):
id = models.BigAutoField()
...
You can hack Django and change the default auto-keys to the right values. Check out:
http://code.djangoproject.com/browser/django/trunk/django/db/backends/mysql/creation.py
from django.conf import settings
from django.db.backends.creation import BaseDatabaseCreation
class DatabaseCreation(BaseDatabaseCreation):
# This dictionary maps Field objects to their associated MySQL column
# types, as strings. Column-type strings can contain format strings; they'll
# be interpolated against the values of Field.__dict__ before being output.
# If a column type is set to None, it won't be included in the output.
data_types = {
'AutoField': 'integer AUTO_INCREMENT',
'BooleanField': 'bool',
'CharField': 'varchar(%(max_length)s)',
You can modify this using a patch in your own code:
DatabaseCreation.data_types['AutoField'] = 'bigint AUTO_INCREMENT'
You will also have to patch the AutoField class:
http://code.djangoproject.com/browser/django/trunk/django/db/models/fields/__init__.py
(untested code, good luck)
http://docs.djangoproject.com/en/dev/topics/db/models/
class BigIntegerField([**options])
available option is :
primary_key
If True, this field is the primary key for the model.
And after all you do a south migration:
ALTER TABLE mytable MODIFY COLUMN myid BIGINT(20) NOT NULL AUTO_INCREMENT;
You are right, sorry. The neccessary snippet is here:
http://djangosnippets.org/snippets/1244/
Allows to create bigint (mysql), bigserial (psql), or NUMBER(19) (oracle) fields which have auto-increment set by using the AutoField of django, therefore ensuring that the ID gets updated in the instance when calling its 'save()' method.
If you would only subclass IntegerField to BigIntegerField and use that as your primary key, your model instance you create would not get the id attribute set when calling 'save()', buy instead you would have to query and load the instance from the DB again to get the ID.
These snippets work. Use the BigAutoField class as your primary key on your model and it works seemlessly without any hacking.