flask_sessions.py 文件源码

def open_session(self, app, request):
        sid = request.cookies.get(app.session_cookie_name)
        if not sid:
            sid = self._generate_sid()
            return self.session_class(sid=sid, permanent=True)

        signer = self._get_signer(app)
        if signer is None:
            return None
        try:
            sid_as_bytes = signer.unsign(sid)
            sid = sid_as_bytes.decode()
        except BadSignature:
            sid = self._generate_sid()
            return self.session_class(sid=sid, permanent=True)

        db_session = SessionManager.Session()
        saved_session = db_session.query(ServerSession).filter(ServerSession.session_id == sid).first()
        if saved_session and not saved_session.expiry and saved_session.expiry <= datetime.utcnow():
            # delete expired session
            db_session.delete(saved_session)
            db_session.commit()
            saved_session = None

        if saved_session:
            try:
                val = saved_session.data
                data = self.serializer.loads(want_bytes(val))
                return self.session_class(data, sid=sid)
            except:
                return self.session_class(sid=sid, permanent=True)

        return self.session_class(sid=sid, permanent=True)