django1/django/contrib/sessions/backends/file.py

108 lines
3.5 KiB
Python

import errno
import os
import tempfile
from django.conf import settings
from django.contrib.sessions.backends.base import SessionBase, CreateError
from django.core.exceptions import SuspiciousOperation, ImproperlyConfigured
class SessionStore(SessionBase):
"""
Implements a file based session store.
"""
def __init__(self, session_key=None):
self.storage_path = getattr(settings, "SESSION_FILE_PATH", None)
if not self.storage_path:
self.storage_path = tempfile.gettempdir()
# Make sure the storage path is valid.
if not os.path.isdir(self.storage_path):
raise ImproperlyConfigured(
"The session storage path %r doesn't exist. Please set your"
" SESSION_FILE_PATH setting to an existing directory in which"
" Django can store session data." % self.storage_path)
self.file_prefix = settings.SESSION_COOKIE_NAME
super(SessionStore, self).__init__(session_key)
def _key_to_file(self, session_key=None):
"""
Get the file associated with this session key.
"""
if session_key is None:
session_key = self.session_key
# Make sure we're not vulnerable to directory traversal. Session keys
# should always be md5s, so they should never contain directory
# components.
if os.path.sep in session_key:
raise SuspiciousOperation(
"Invalid characters (directory components) in session key")
return os.path.join(self.storage_path, self.file_prefix + session_key)
def load(self):
session_data = {}
try:
session_file = open(self._key_to_file(), "rb")
try:
try:
session_data = self.decode(session_file.read())
except (EOFError, SuspiciousOperation):
self.create()
finally:
session_file.close()
except IOError:
pass
return session_data
def create(self):
while True:
self._session_key = self._get_new_session_key()
try:
self.save(must_create=True)
except CreateError:
continue
self.modified = True
self._session_cache = {}
return
def save(self, must_create=False):
flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC | getattr(os, 'O_BINARY', 0)
if must_create:
flags |= os.O_EXCL
# Because this may trigger a load from storage, we must do it before
# truncating the file to save.
session_data = self._get_session(no_load=must_create)
try:
fd = os.open(self._key_to_file(self.session_key), flags)
try:
os.write(fd, self.encode(session_data))
finally:
os.close(fd)
except OSError, e:
if must_create and e.errno == errno.EEXIST:
raise CreateError
raise
except (IOError, EOFError):
pass
def exists(self, session_key):
if os.path.exists(self._key_to_file(session_key)):
return True
return False
def delete(self, session_key=None):
if session_key is None:
if self._session_key is None:
return
session_key = self._session_key
try:
os.unlink(self._key_to_file(session_key))
except OSError:
pass
def clean(self):
pass