基于当前登录用户的Django数据库路由

Question

In a view class, you could call self.request.user and perform actions based on that. In my case, I would like to be able to switch databases depending on the current user logged in. Is there anyway to inject a self.request call into the db_for_read() and db_for_write() methods like in the following?

class DataBaseRouter(object):

    def db_for_read(self, model, **hints):
        user = self.request.user
        if user.id == 1:
            return "master"
        return "default"

    def db_for_write(self, model, **hints):
        user = self.request.user
        if user.id == 1:
            return "master"
        return "default"

Answer 1

You can use a RouterMiddlewear to check if what user is logged in and then redirect all the queries to a particular database of your choice, this would be help full if you are using view based execution of the queries.

class RouterMiddleware (object):

    def process_view( self, request, view_func, args, kwargs ):
        # Check the user logged in
        user = self.request.user
        # Call your functions to set the database by passing the user.id



    def process_response( self, request, response ):
        # Make the database to default here if you wish to use it no longer

        return response


class DataBaseRouter(object):

    def db_for_read(self, model, user_id=None, **hints):
       if user.id == 1:
            return "master"
        return "default"

    def db_for_write(self, model, user_id=None, **hints):
        if user.id == 1:
            return "master"
        return "default"

Here is the link that I have modified for your requirement.

Make sure you add the the RouterMiddleware to your MIDDLEWARE_CLASSES .

Answer 2

Try this django dynamic db router package . its very simple. install it and configure and use as below.

settings.py

DATABASES = {
'default': {
    'ENGINE': 'django.db.backends.postgresql_psycopg2',
    'NAME': 'my_local_database',
    'USER': 'postgres',
    'PASSWORD': 'my-pass',
    'HOST': '127.0.0.1',
    'PORT': '5432',
},
'master': {
    'ENGINE': 'django.db.backends.postgresql_psycopg2',
    'NAME': 'my_master_database',
    'USER': 'postgres',
    'PASSWORD': 'my-pass',
    'HOST': 'example.com',
    'PORT': '5432',
},
}
DATABASE_ROUTERS = ['dynamic_db_router.DynamicDbRouter']

my_app/views.py

from dynamic_db_router import in_database

from my_app.models import MyModel

def index(request):
     #Picking the DB based on logged in user or you can do this in middile ware as well.
     use_db = "default"
     user = self.request.user
     if user.id == 1:
        use_db = "master"
     # Fetching data from selected databases. 
     with in_database(use_db):
         input = MyModel.objects.filter(field_a="okay")
         output = complex_query_function(input)

Answer 3

To resolve this, I created a new model with just one userid field. Then in router when specifying db for read and write, I get the data from that model so I don't need any request argument.
And I just added a short ajax code in my base template so whenever my website is opened it gets the userid from request.user and change the model row so current user id is changed like so.