You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
123 lines
4.3 KiB
123 lines
4.3 KiB
import time
|
|
import warnings
|
|
from datetime import timedelta as TimeDelta
|
|
from typing import Any, Optional, Protocol
|
|
|
|
from flask import Flask
|
|
|
|
from .._utils import total_seconds
|
|
from ..base import ServerSideSession, ServerSideSessionInterface
|
|
from ..defaults import Defaults
|
|
|
|
|
|
class MemcacheClientProtocol(Protocol):
|
|
def get(self, key: str) -> Optional[Any]: ...
|
|
def set(self, key: str, value: Any, timeout: int) -> bool: ...
|
|
def delete(self, key: str) -> bool: ...
|
|
|
|
|
|
class MemcachedSession(ServerSideSession):
|
|
pass
|
|
|
|
|
|
class MemcachedSessionInterface(ServerSideSessionInterface):
|
|
"""A Session interface that uses memcached as session storage. (`pylibmc`, `libmc`, `python-memcached` or `pymemcache` required)
|
|
|
|
:param client: A ``memcache.Client`` instance.
|
|
:param key_prefix: A prefix that is added to all storage keys.
|
|
:param use_signer: Whether to sign the session id cookie or not.
|
|
:param permanent: Whether to use permanent session or not.
|
|
:param sid_length: The length of the generated session id in bytes.
|
|
:param serialization_format: The serialization format to use for the session data.
|
|
|
|
.. versionadded:: 0.7
|
|
The `serialization_format` and `app` parameters were added.
|
|
|
|
.. versionadded:: 0.6
|
|
The `sid_length` parameter was added.
|
|
|
|
.. versionadded:: 0.2
|
|
The `use_signer` parameter was added.
|
|
"""
|
|
|
|
serializer = ServerSideSessionInterface.serializer
|
|
session_class = MemcachedSession
|
|
ttl = True
|
|
|
|
def __init__(
|
|
self,
|
|
app: Flask,
|
|
client: Optional[MemcacheClientProtocol] = Defaults.SESSION_MEMCACHED,
|
|
key_prefix: str = Defaults.SESSION_KEY_PREFIX,
|
|
use_signer: bool = Defaults.SESSION_USE_SIGNER,
|
|
permanent: bool = Defaults.SESSION_PERMANENT,
|
|
sid_length: int = Defaults.SESSION_ID_LENGTH,
|
|
serialization_format: str = Defaults.SESSION_SERIALIZATION_FORMAT,
|
|
):
|
|
if client is None or not all(
|
|
hasattr(client, method) for method in ["get", "set", "delete"]
|
|
):
|
|
warnings.warn(
|
|
"No valid memcache.Client instance provided, attempting to create a new instance on localhost with default settings.",
|
|
RuntimeWarning,
|
|
stacklevel=1,
|
|
)
|
|
client = self._get_preferred_memcache_client()
|
|
self.client = client
|
|
super().__init__(
|
|
app, key_prefix, use_signer, permanent, sid_length, serialization_format
|
|
)
|
|
|
|
def _get_preferred_memcache_client(self):
|
|
clients = [
|
|
("pylibmc", ["127.0.0.1:11211"]),
|
|
("memcache", ["127.0.0.1:11211"]), # python-memcached
|
|
("pymemcache.client.base", "127.0.0.1:11211"),
|
|
("libmc", ["localhost:11211"]),
|
|
]
|
|
|
|
for module_name, server in clients:
|
|
try:
|
|
module = __import__(module_name)
|
|
ClientClass = module.Client
|
|
return ClientClass(server)
|
|
except ImportError:
|
|
continue
|
|
|
|
raise ImportError("No memcache module found")
|
|
|
|
def _get_memcache_timeout(self, timeout: int) -> int:
|
|
"""
|
|
Memcached deals with long (> 30 days) timeouts in a special
|
|
way. Call this function to obtain a safe value for your timeout.
|
|
"""
|
|
if timeout > 2592000: # 60*60*24*30, 30 days
|
|
# Switch to absolute timestamps.
|
|
timeout += int(time.time())
|
|
return timeout
|
|
|
|
def _retrieve_session_data(self, store_id: str) -> Optional[dict]:
|
|
# Get the saved session (item) from the database
|
|
serialized_session_data = self.client.get(store_id)
|
|
if serialized_session_data:
|
|
return self.serializer.decode(serialized_session_data)
|
|
return None
|
|
|
|
def _delete_session(self, store_id: str) -> None:
|
|
self.client.delete(store_id)
|
|
|
|
def _upsert_session(
|
|
self, session_lifetime: TimeDelta, session: ServerSideSession, store_id: str
|
|
) -> None:
|
|
storage_time_to_live = total_seconds(session_lifetime)
|
|
|
|
# Serialize the session data
|
|
serialized_session_data = self.serializer.encode(session)
|
|
|
|
# Update existing or create new session in the database
|
|
self.client.set(
|
|
store_id,
|
|
serialized_session_data,
|
|
self._get_memcache_timeout(storage_time_to_live),
|
|
)
|