app/django/contrib/sessions/backends/db.py
author Sverre Rabbelier <srabbelier@gmail.com>
Thu, 05 Feb 2009 23:52:27 +0000
changeset 1230 b1b1897e4df1
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Cleanup in org_app and replace ReferenceProperty with LinkProperty Using LinkProperty allows the org to host their idea's list on Melange through the Document system, and then specify the URL of that document. This also makes it possible for the orgs to specify a document that is not hosted on Melange. Patch by: Sverre Rabbelier

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