Hi Pablo,
As suggested Larry this can be like SSO implementation in one of sites hosted by your Django server.
But this can be done in more simple way because all sites are hosted within the same Django server.
Possible Workflow:
===============
Terms
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'SSO Site' - one of the sites which we should specify as main SSO server - main(central) application.
'Some Site' - any other site hosted on the same Django project except SSO site.
1. on Some Site user clicks 'Login'
2. SSO Site redirects user to soo view of SSO Site
3. sso view checks if user already logged in
4. if not redirects user on login page of SSO Site
5. sso view generates one time token and redirects user back on authenticate view of Some Site
6. authenticate view checks for token and if token valid and user was redirected from SSO Site retrieves user from that token and authenticate it into current session of Some Site.
I did not not find any way how to login user to all sites in advance. Session token stores in browser cookies and user authentication should be finished on the page that belongs to Some Site. User should initiate that login process either explicitly by clicking on 'Login' link or implicitly by redirecting from view that require authorization.
For the same reason I did not find how to request SSO from the page which is not belongs to domain for which user should be authenticated as you asked below.
Does it make any sense to you?
Regards,
Constantine C.