I want to create a couple of Object's in django model.
Such as Room[idRoom, nameRoom] and User[idUser, nameUser].
I want to have multiple Users in Room's and Room's for User.
I want to get all user's in specific Room and all Rooms by the User.
Also, I want to make History of changing for Room and User table.
Anybody can help me with this?
This is a sketch of what you will need to have:
class User(models.Model):
pass
class Room(models.Model):
users = models.ManyToManyField(User, related_name="rooms")
class History(models.Model):
room = models.ForeignKey(Room)
user = models.ForeignKey(User)
time = models.DateTimeField(auto_now_add=True)
# add some objects
first_user = User()
first_user.save()
first_room = Room()
first_room.save()
first_user.rooms.add(first_room)
History(room=first_room, user=first_user).save()
# ^^^ it automatically adds the current date and time
# now fetch them like this:
Room.objects.get(pk=the_room).users.all()
User.objects.get(pk=the_user).rooms.all()
User.objects.get(pk=the_user).history_set.order_by("-time")
Related
I have a simple model:
class Item(models.Model):
user = ForeignKey(User, related_name="user_items")
users = ManyToManyField(User, related_name="users_items")
I want it so that when a user creates an Item via ViewSet, that user is automatically assigned to the user and users fields.
I typically do this for ForeignKey's via the ViewSet's perform_create:
class ItemViewSet(viewsets.ModelViewSet):
...
def perform_create(self, serializer):
if self.request.user.is_authenticated:
serializer.save(user=self.request.user)
else:
serializer.save()
When I try to do it for the ManyToManyField too, I get this error:
{'users': [ErrorDetail(string='This list may not be empty.', code='empty')]}
I've tried the following in perform_create():
# 1
serializer.save(user=self.request.user, users=self.request.user)
# 2
serializer.save(user=self.request.user, users=[self.request.user])
# 2
serializer.save(user=self.request.user, users=[self.request.user.id])
How can I update a ManyToManyField via a ViewSet's perform_create?
Edit:
I guess the following works:
obj = serializer.save(user=self.request.user)
obj.users.add(self.request.user)
Is there no way to have the M2M field when the object is initially created though?
when you want set a list to m2m field one of the things you can do is this:
item_obj.users.set(user_list)
probably you need first get your item_obj.
for this you can get your object id from item_id = serializer.data.get('id') , and then item_obj = Item.objects.get(id = item_id)
I am new to ndb and gae and have a problem coming up with a good solution setting indexes.
Let say we have a user model like this:
class User(ndb.Model):
name = ndb.StringProperty()
email = ndb.StringProperty(required = True)
fb_id = ndb.StringProperty()
Upon login if I was going to check against the email address with a query, I believe this would be quite slow and inefficient. Possibly it has to do a full table scan.
q = User.query(User.email == EMAIL)
user = q.fetch(1)
I believe it would be much faster, if User models were saved with the email as their key.
user = user(id=EMAIL)
user.put()
That way I could retrieve them like this a lot faster (so I believe)
key = ndb.Key('User', EMAIL)
user = key.get()
So far if I am wrong please correct me. But after implementing this I realized there is a chance that facebook users would change their email address, that way upon a new oauth2.0 connection their new email can't be recognized in the system and they will be created as a new user. Hence maybe I should use a different approach:
Using the social-media-provider-id (unique for all provider users)
and
provider-name (in rare case that two twitter and facebook users share
the same provider-id)
However in order to achieve this, I needed to set two indexes, which I believe is not possible.
So what could I do? Shall I concatenate both fields as a single key and index on that?
e.g. the new idea would be:
class User(ndb.Model):
name = ndb.StringProperty()
email = ndb.StringProperty(required = True)
provider_id = ndb.StringProperty()
provider_type = ndb.StringProperty()
saving:
provider_id = 1234
provider_type = fb
user = user(id=provider_id + provider_type)
user.put()
retrieval:
provider_id = 1234
provider_type = fb
key = ndb.Key('User', provider_id + provider_type)
user = key.get()
This way we don't care any more if the user changes the email address on his social media.
Is this idea sound?
Thanks,
UPDATE
Tim's solution sounded so far the cleanest and likely also the fastest to me. But I came across a problem.
class AuthProvider(polymodel.PolyModel):
user_key = ndb.KeyProperty(kind=User)
active = ndb.BooleanProperty(default=True)
date_created = ndb.DateTimeProperty(auto_now_add=True)
#property
def user(self):
return self.user_key.get()
class FacebookLogin(AuthProvider):
pass
View.py: Within facebook_callback method
provider = ndb.Key('FacebookLogin', fb_id).get()
# Problem is right here. provider is always None. Only if I used the PolyModel like this:
# ndb.Key('AuthProvider', fb_id).get()
#But this defeats the whole purpose of having different sub classes as different providers.
#Maybe I am using the key handeling wrong?
if provider:
user = provider.user
else:
provider = FacebookLogin(id=fb_id)
if not user:
user = User()
user_key = user.put()
provider.user_key = user_key
provider.put()
return user
One slight variation on your approach which could allow a more flexible model will be to create a separate entity for the provider_id, provider_type, as the key or any other auth scheme you come up with
This entity then holds a reference (key) of the actual user details.
You can then
do a direct get() for the auth details, then get() the actual user details.
The auth details can be changed without actually rewriting/rekeying the user details
You can support multiple auth schemes for a single user.
I use this approach for an application that has > 2000 users, most use a custom auth scheme (app specific userid/passwd) or google account.
e.g
class AuthLogin(ndb.Polymodel):
user_key = ndb.KeyProperty(kind=User)
status = ndb.StringProperty() # maybe you need to disable a particular login with out deleting it.
date_created = ndb.DatetimeProperty(auto_now_add=True)
#property
def user(self):
return self.user_key.get()
class FacebookLogin(AuthLogin):
# some additional facebook properties
class TwitterLogin(AuthLogin):
# Some additional twitter specific properties
etc...
By using PolyModel as the base class you can do a AuthLogin.query().filter(AuthLogin.user_key == user.key) and get all auth types defined for that user as they all share the same base class AuthLogin. You need this otherwise you would have to query in turn for each supported auth type, as you can not do a kindless query without an ancestor, and in this case we can't use the User as the ancestor becuase then we couldn't do a simple get() to from the login id.
However some things to note, all subclasses of AuthLogin will share the same kind in the key "AuthLogin" so you still need to concatenate the auth_provider and auth_type for the keys id so that you can ensure you have unique keys. E.g.
dev~fish-and-lily> from google.appengine.ext.ndb.polymodel import PolyModel
dev~fish-and-lily> class X(PolyModel):
... pass
...
dev~fish-and-lily> class Y(X):
... pass
...
dev~fish-and-lily> class Z(X):
... pass
...
dev~fish-and-lily> y = Y(id="abc")
dev~fish-and-lily> y.put()
Key('X', 'abc')
dev~fish-and-lily> z = Z(id="abc")
dev~fish-and-lily> z.put()
Key('X', 'abc')
dev~fish-and-lily> y.key.get()
Z(key=Key('X', 'abc'), class_=[u'X', u'Z'])
dev~fish-and-lily> z.key.get()
Z(key=Key('X', 'abc'), class_=[u'X', u'Z'])
This is the problem you ran into. By adding the provider type as part of the key you now get distinct keys.
dev~fish-and-lily> z = Z(id="Zabc")
dev~fish-and-lily> z.put()
Key('X', 'Zabc')
dev~fish-and-lily> y = Y(id="Yabc")
dev~fish-and-lily> y.put()
Key('X', 'Yabc')
dev~fish-and-lily> y.key.get()
Y(key=Key('X', 'Yabc'), class_=[u'X', u'Y'])
dev~fish-and-lily> z.key.get()
Z(key=Key('X', 'Zabc'), class_=[u'X', u'Z'])
dev~fish-and-lily>
I don't believe this is any less convenient a model for you.
Does all that make sense ;-)
While #Greg's answer seems OK, I think it's actually a bad idea to associate an external type/id as a key for your entity, because this solution doesn't scale very well.
What if you would like to implement your own username/password at one point?
What if the user going to delete their Facebook account?
What if the same user wants to sign in with a Twitter account as well?
What if the user has more than one Facebook accounts?
So the idea of having the type/id as key looks weak. A better solution would be to have a field for every type to store only the id. For example facebook_id, twitter_id, google_id etc, then query on these fields to retrieve the actual user. This will happen during sign-in and signup process so it's not that often. Of course you will have to add some logic to add another provider for an already existed user or merge users if the same user signed in with a different provider.
Still the last solution won't work if you want to support multiple sign-ins from the same provider. In order to achieve that you will have to create another model that will store only the external providers/ids and associate them with your user model.
As an example of the second solution you could check my gae-init project where I'm storing the 3 different providers in the User model and working on them in the auth.py module. Again this solution doesn't not scale very well with more providers and doesn't support multiple IDs from the same provider.
Concatenating the user-type with their ID is sensible.
You can save on your read and write costs by not duplicating the type and ID as properties though - when you need to use them, just split the ID back up. (Doing this will be simpler if you include a separator between the parts, '%s|%s' % (provider_type, provider_id) for example)
If you want to use a single model, you can do something like:
class User(ndb.Model):
name = ndb.StringProperty()
email = ndb.StringProperty(required = True)
providers = ndb.KeyProperty(repeated=True)
auser = User(id="auser", name="A user", email="auser#example.com")
auser.providers = [
ndb.Key("ProviderName", "fb", "ProviderId", 123),
ndb.Key("ProviderName", "tw", "ProviderId", 123)
]
auser.put()
To query for a specific FB login, you simple do:
fbkey = ndb.Key("ProviderName", "fb", "ProviderId", 123)
for entry in User.query(User.providers==fbkey):
# Do something with the entry
As ndb does not provide an easy way to create a unique constraint, you could use the _pre_put_hook to ensure that providers is unique.
I'm implementing a user filter system on a website. Users are to be able to select 'categories' and 'packages' of interest to them and have the matching data presented when they log in. Both sets of data will come from HTML select forms eg. Categories: 'null pointers', 'dead code'... and packages 'package_x', 'package_y', 'package_z'...
My question is about the best way to store this list information in a database (I am using Django and PostgresSQL).
My initial thought is to have a table like this:
user_id - one to one field
categories - textfield - store json data
packages - textfield - store json data
Is there a better way to be doing this?
I would go the route of using a user profile with categories and packages being many to many fields.
In models.py
from django.contrib.auth.models import User
class Category(models.Model):
name = models.CharField(max_length=255)
class Package(models.Model):
name = models.CharField(max_length=255)
class UserProfile(models.Model):
user = models.ForiegnKey(User)
categories = models.ManyToManyField(Category)
packages = models.ManyToManyField(Package)
In admin.py
from django.contrib.auth.admin import UserAdmin
from django.contrib.auth.models import User
class CustomUserAdmin(UserAdmin):
inlines = [UserProfile]
#filter_horizontal = ('',) #Makes the selection a bit more friendly
admin.site.unregister(User)
admin.site.register(User, CustomUserAdmin)
In views.py
user_with_profile = User.objects.get(pk=user_id).get_profile()
All that being said. Django 1.5 will replace the user profile with being able to use a configurable user model.
I have the following model structure
class User(db.Model) :
nickname = db.StringProperty(required=True)
fullname = db.StringProperty(required=True)
class Article(db.Model) :
title = db.StringProperty(required=True)
body = db.StringProperty(required=True)
author = db.ReferenceProperty(User, required=True)
class Favorite(db.Model) :
who = db.ReferenceProperty(User, required=True)
what = db.ReferenceProperty(Article, required=True)
I'd like to display 10 last articles according to this pattern: article.title, article.body, article.author(nickname), info if this article has been already favorited by the signed in user.
I have added a function which I use to get the authors of these articles using only one query (it is described here)
But I don't know what to do with the favorites (I'd like to know which of the displayed articles have been favorited by me using less than 10 queries (I want to display 10 articles)). Is it possible?
You can actually do this with an amortized cost of 0 queries if you denormalize your data more! Add a favorites property to Authors which stores a list of keys of articles which the user has favorited. Then you can determine if the article is the user's favorite by simply checking this list.
If you retrieve this list of favorites when the user first logs in and just store it in your user's session data (and update it when the user adds/removes a favorite), then you won't have to query the datastore to check to see if an item is a favorite.
Suggested update to the Authors model:
class Authors(db.Model): # I think this would be better named "User"
# same properties you already had ...
favorites = db.ListProperty(db.Key, required=True, default=[])
When the user logs in, just cache their list of favorites in your session data:
session['favs'] = user.favorites
Then when you show the latest articles, you can check if they are a favorite just by seeing if each article's key is in the favorites list you cached already (or you could dynamically query the favorites list but there is really no need to).
favs = session['favs']
articles = get_ten_latest_articles()
for article in articles:
if article.key() in favs:
# ...
I think there is one more solution.
Let's add 'auto increment' fields to the User and Article class.
Then, when we want to add an entry to the Favorite class, we will also add the key name in the format which we will be able to know having auto increment value of the signed in user and the article, like this 'UserId'+id_of_the_user+'ArticleId'+id_of_an_article.
Then, when it comes to display, we will easily predict key names of the favorites and would be able to use Favorite.get_by_key_name(key_names).
An alternative solution to dound's is to store the publication date of the favorited article on the Favorite entry. Then, simply sort by that when querying.
i'm experimenting with django and the builtin admin interface.
I basically want to have a field that is a drop down in the admin UI. The drop down choices should be all the directories available in a specified directory.
If i define a field like this:
test_folder_list = models.FilePathField(path=/some/file/path)
it shows me all the files in the directory, but not the directories.
Does anyone know how i can display the folders?
also i tried doing
test_folder_list = models.charField(max_length=100, choices=SOME_LIST)
where SOME_LIST is a list i populate using some custom code to read the folders in a directory. This works but it doesn't refresh. i.e. the choice list is limited to a snapshot of whatever was there when running the app for the first time.
thanks in advance.
update:
after some thinking and research i discovered what i want may be to either
1. create my own widget that is based on forms.ChoiceField
or
2. pass my list of folders to the choice list when it is rendered to the client
for 1. i tried a custom widget.
my model looks like
class Test1(models.Model):
test_folder_ddl = models.CharField(max_length=100)
then this is my custom widget:
class FolderListDropDown(forms.Select):
def __init__(self, attrs=None, target_path):
target_folder = '/some/file/path'
dir_contents = os.listdir(target_folder)
directories = []
for item in dir_contents:
if os.path.isdir(''.join((target_folder,item,))):
directories.append((item, item),)
folder_list = tuple(directories)
super(FolderListDropDown, self).__init__(attrs=attrs, choices=folder_list)
then i did this in my modelForm
class test1Form(ModelForm):
test_folder_ddl = forms.CharField(widget=FolderListDropDown())
and it didn't seem to work.What i mean by that is django didn't want to use my widget and instead rendered the default textinput you get when you use a CharField.
for 2. I tried this in my ModelForm
class test1Form(ModelForm):
test_folder_ddl = forms.CharField(widget=FolderListDropDown())
test_folder_ddl.choices = {some list}
I also tried
class test1Form(ModelForm):
test_folder_ddl = forms.ChoiceField(choices={some list})
and it would still render the default char field widget.
Anyone know what i'm doing wrong?
Yay solved. after beating my head all day and going through all sorts of examples by people i got this to work.
basically i had the right idea with #2. The steps are
- Create a ModelForm of our model
- override the default form field user for a models.CharField. i.e. we want to explcitly say use a choiceField.
- Then we have to override how the form is instantiated so that we call the thing we want to use to generate our dynamic list of choices
- then in our ModelAdmin make sure we explicitly tell the admin to use our ModelForm
class Test1(models.Model):
test_folder_ddl = models.CharField(max_length=100)
class Test1Form(ModelForm):
test_folder_ddl = forms.choiceField()
def __init__(self, *args, **kwargs):
super(Test1Form, self).__init__(*args, **kwargs)
self.fields['test_folder_ddl'].choices = utility.get_folder_list()
class Test1Admin(admin.ModelAdmin):
form = Test1Form
I use a generator:
see git://gist.github.com/1118279.git
import pysvn
class SVNChoices(DynamicChoice):
"""
Generate a choice from somes files in a svn repo
""""
SVNPATH = 'http://xxxxx.com/svn/project/trunk/choices/'
def generate(self):
def get_login( realm, username, may_save ):
return True, 'XXX', 'xxxxx', True
client = pysvn.Client()
client.callback_get_login = get_login
return [os.path.basename(sql[0].repos_path) for sql in client.list(self.SVNPATH)[1:]]