1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
from __future__ import annotations
from abc import ABC, abstractmethod
from typing import (
TYPE_CHECKING,
Any,
Awaitable,
Callable,
Generic,
Literal,
TypeVar,
cast,
)
from litestar.connection import ASGIConnection
from litestar.enums import ScopeType
from litestar.middleware.base import AbstractMiddleware, DefineMiddleware
from litestar.serialization import decode_json, encode_json
from litestar.utils import get_serializer_from_scope
__all__ = ("BaseBackendConfig", "BaseSessionBackend", "SessionMiddleware")
if TYPE_CHECKING:
from litestar.types import ASGIApp, Message, Receive, Scope, Scopes, ScopeSession, Send
ONE_DAY_IN_SECONDS = 60 * 60 * 24
ConfigT = TypeVar("ConfigT", bound="BaseBackendConfig")
BaseSessionBackendT = TypeVar("BaseSessionBackendT", bound="BaseSessionBackend")
class BaseBackendConfig(ABC, Generic[BaseSessionBackendT]): # pyright: ignore
"""Configuration for Session middleware backends."""
_backend_class: type[BaseSessionBackendT] # pyright: ignore
key: str
"""Key to use for the cookie inside the header, e.g. ``session=<data>`` where ``session`` is the cookie key and
``<data>`` is the session data.
Notes:
- If a session cookie exceeds 4KB in size it is split. In this case the key will be of the format
``session-{segment number}``.
"""
max_age: int
"""Maximal age of the cookie before its invalidated."""
scopes: Scopes = {ScopeType.HTTP, ScopeType.WEBSOCKET}
"""Scopes for the middleware - options are ``http`` and ``websocket`` with the default being both"""
path: str
"""Path fragment that must exist in the request url for the cookie to be valid.
Defaults to ``'/'``.
"""
domain: str | None
"""Domain for which the cookie is valid."""
secure: bool
"""Https is required for the cookie."""
httponly: bool
"""Forbids javascript to access the cookie via 'Document.cookie'."""
samesite: Literal["lax", "strict", "none"]
"""Controls whether or not a cookie is sent with cross-site requests.
Defaults to ``lax``.
"""
exclude: str | list[str] | None
"""A pattern or list of patterns to skip in the session middleware."""
exclude_opt_key: str
"""An identifier to use on routes to disable the session middleware for a particular route."""
@property
def middleware(self) -> DefineMiddleware:
"""Use this property to insert the config into a middleware list on one of the application layers.
Examples:
.. code-block:: python
from os import urandom
from litestar import Litestar, Request, get
from litestar.middleware.sessions.cookie_backend import CookieBackendConfig
session_config = CookieBackendConfig(secret=urandom(16))
@get("/")
def my_handler(request: Request) -> None: ...
app = Litestar(route_handlers=[my_handler], middleware=[session_config.middleware])
Returns:
An instance of DefineMiddleware including ``self`` as the config kwarg value.
"""
return DefineMiddleware(SessionMiddleware, backend=self._backend_class(config=self))
class BaseSessionBackend(ABC, Generic[ConfigT]):
"""Abstract session backend defining the interface between a storage mechanism and the application
:class:`SessionMiddleware`.
This serves as the base class for all client- and server-side backends
"""
__slots__ = ("config",)
def __init__(self, config: ConfigT) -> None:
"""Initialize ``BaseSessionBackend``
Args:
config: A instance of a subclass of ``BaseBackendConfig``
"""
self.config = config
@staticmethod
def serialize_data(data: ScopeSession, scope: Scope | None = None) -> bytes:
"""Serialize data into bytes for storage in the backend.
Args:
data: Session data of the current scope.
scope: A scope, if applicable, from which to extract a serializer.
Notes:
- The serializer will be extracted from ``scope`` or fall back to
:func:`default_serializer <.serialization.default_serializer>`
Returns:
``data`` serialized as bytes.
"""
serializer = get_serializer_from_scope(scope) if scope else None
return encode_json(data, serializer)
@staticmethod
def deserialize_data(data: Any) -> dict[str, Any]:
"""Deserialize data into a dictionary for use in the application scope.
Args:
data: Data to be deserialized
Returns:
Deserialized data as a dictionary
"""
return cast("dict[str, Any]", decode_json(value=data))
@abstractmethod
def get_session_id(self, connection: ASGIConnection) -> str | None:
"""Try to fetch session id from connection ScopeState. If one does not exist, generate one.
Args:
connection: Originating ASGIConnection containing the scope
Returns:
Session id str or None if the concept of a session id does not apply.
"""
@abstractmethod
async def store_in_message(self, scope_session: ScopeSession, message: Message, connection: ASGIConnection) -> None:
"""Store the necessary information in the outgoing ``Message``
Args:
scope_session: Current session to store
message: Outgoing send-message
connection: Originating ASGIConnection containing the scope
Returns:
None
"""
@abstractmethod
async def load_from_connection(self, connection: ASGIConnection) -> dict[str, Any]:
"""Load session data from a connection and return it as a dictionary to be used in the current application
scope.
Args:
connection: An ASGIConnection instance
Returns:
The session data
Notes:
- This should not modify the connection's scope. The data returned by this
method will be stored in the application scope by the middleware
"""
class SessionMiddleware(AbstractMiddleware, Generic[BaseSessionBackendT]):
"""Litestar session middleware for storing session data."""
def __init__(self, app: ASGIApp, backend: BaseSessionBackendT) -> None:
"""Initialize ``SessionMiddleware``
Args:
app: An ASGI application
backend: A :class:`BaseSessionBackend` instance used to store and retrieve session data
"""
super().__init__(
app=app,
exclude=backend.config.exclude,
exclude_opt_key=backend.config.exclude_opt_key,
scopes=backend.config.scopes,
)
self.backend = backend
def create_send_wrapper(self, connection: ASGIConnection) -> Callable[[Message], Awaitable[None]]:
"""Create a wrapper for the ASGI send function, which handles setting the cookies on the outgoing response.
Args:
connection: ASGIConnection
Returns:
None
"""
async def wrapped_send(message: Message) -> None:
"""Wrap the ``send`` function.
Declared in local scope to make use of closure values.
Args:
message: An ASGI message.
Returns:
None
"""
if message["type"] != "http.response.start":
await connection.send(message)
return
scope_session = connection.scope.get("session")
await self.backend.store_in_message(scope_session, message, connection)
await connection.send(message)
return wrapped_send
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
"""ASGI-callable.
Args:
scope: The ASGI connection scope.
receive: The ASGI receive function.
send: The ASGI send function.
Returns:
None
"""
connection = ASGIConnection[Any, Any, Any, Any](scope, receive=receive, send=send)
scope["session"] = await self.backend.load_from_connection(connection)
connection._connection_state.session_id = self.backend.get_session_id(connection) # pyright: ignore [reportGeneralTypeIssues]
await self.app(scope, receive, self.create_send_wrapper(connection))
|
