1from __future__ import annotations
 2
 3import time
 4
 5from opentelemetry import trace
 6from opentelemetry.semconv._incubating.attributes.session_attributes import SESSION_ID
 7
 8from plain.http import HttpMiddleware, Request, Response
 9from plain.runtime import settings
10from plain.utils.cache import patch_vary_headers
11from plain.utils.http import http_date
12
13from .core import SessionStore
14from .requests import get_request_session, set_request_session
15
16
17class SessionMiddleware(HttpMiddleware):
18    def process_request(self, request: Request) -> Response:
19        session_key = request.cookies.get(settings.SESSION_COOKIE_NAME)
20
21        session = SessionStore(session_key)
22        set_request_session(request, session)
23
24        if session.model_instance:
25            trace.get_current_span().set_attribute(
26                SESSION_ID, session.model_instance.id
27            )
28
29        response = self.get_response(request)
30
31        """
32        If request.session was modified, or if the configuration is to save the
33        session every time, save the changes and set a session cookie or delete
34        the session cookie if the session has been emptied.
35        """
36        session = get_request_session(request)
37        accessed = session.accessed
38        modified = session.modified
39        empty = session.is_empty()
40
41        # First check if we need to delete this cookie.
42        # The session should be deleted only if the session is entirely empty.
43        if settings.SESSION_COOKIE_NAME in request.cookies and empty:
44            response.delete_cookie(
45                settings.SESSION_COOKIE_NAME,
46                path=settings.SESSION_COOKIE_PATH,
47                domain=settings.SESSION_COOKIE_DOMAIN,
48                samesite=settings.SESSION_COOKIE_SAMESITE,
49            )
50            patch_vary_headers(response, ["Cookie"])
51        else:
52            if accessed:
53                patch_vary_headers(response, ["Cookie"])
54            if (modified or settings.SESSION_SAVE_EVERY_REQUEST) and not empty:
55                if settings.SESSION_EXPIRE_AT_BROWSER_CLOSE:
56                    max_age = None
57                    expires = None
58                else:
59                    max_age = settings.SESSION_COOKIE_AGE
60                    expires_time = time.time() + max_age
61                    expires = http_date(expires_time)
62                # Save the session data and refresh the client cookie.
63                # Skip session save for 5xx responses.
64                if response.status_code < 500:
65                    session.save()
66                    response.set_cookie(
67                        settings.SESSION_COOKIE_NAME,
68                        session.session_key,
69                        max_age=max_age,
70                        expires=expires,
71                        domain=settings.SESSION_COOKIE_DOMAIN,
72                        path=settings.SESSION_COOKIE_PATH,
73                        secure=settings.SESSION_COOKIE_SECURE or None,
74                        httponly=settings.SESSION_COOKIE_HTTPONLY or None,
75                        samesite=settings.SESSION_COOKIE_SAMESITE,
76                    )
77        return response