app/django/contrib/sessions/backends/db.py
author Daniel Bentley <dbentley@google.com>
Wed, 15 Apr 2009 08:01:17 +0000
changeset 2184 a1bda9afa5d0
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Step 2 of moving to new seeding model. Create Seeder class, which abstracts some seeding. Move user to Seeder class, and make new OrganizationSeeder class. If people like this, I'll finish the rest soon. Patch by: Dan Bentley

import datetime
from django.contrib.sessions.models import Session
from django.contrib.sessions.backends.base import SessionBase, CreateError
from django.core.exceptions import SuspiciousOperation
from django.db import IntegrityError, transaction
from django.utils.encoding import force_unicode

class SessionStore(SessionBase):
    """
    Implements database session store.
    """
    def load(self):
        try:
            s = Session.objects.get(
                session_key = self.session_key,
                expire_date__gt=datetime.datetime.now()
            )
            return self.decode(force_unicode(s.session_data))
        except (Session.DoesNotExist, SuspiciousOperation):
            self.create()
            return {}

    def exists(self, session_key):
        try:
            Session.objects.get(session_key=session_key)
        except Session.DoesNotExist:
            return False
        return True

    def create(self):
        while True:
            self.session_key = self._get_new_session_key()
            try:
                # Save immediately to ensure we have a unique entry in the
                # database.
                self.save(must_create=True)
            except CreateError:
                # Key wasn't unique. Try again.
                continue
            self.modified = True
            self._session_cache = {}
            return

    def save(self, must_create=False):
        """
        Saves the current session data to the database. If 'must_create' is
        True, a database error will be raised if the saving operation doesn't
        create a *new* entry (as opposed to possibly updating an existing
        entry).
        """
        obj = Session(
            session_key = self.session_key,
            session_data = self.encode(self._get_session(no_load=must_create)),
            expire_date = self.get_expiry_date()
        )
        sid = transaction.savepoint()
        try:
            obj.save(force_insert=must_create)
        except IntegrityError:
            if must_create:
                transaction.savepoint_rollback(sid)
                raise CreateError
            raise

    def delete(self, session_key=None):
        if session_key is None:
            if self._session_key is None:
                return
            session_key = self._session_key
        try:
            Session.objects.get(session_key=session_key).delete()
        except Session.DoesNotExist:
            pass