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=self.permanent)
        if self.use_signer:
            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=self.permanent)

        full_session_key = self._encode_key(self.key_prefix) + self._encode_key(sid)
        val = self.client.get(full_session_key)
        if val is not None:
            try:
                if not PY2:
                    val = want_bytes(val)
                data = self.serializer.loads(val)
                return self.session_class(data, sid=sid)
            except:
                return self.session_class(sid=sid, permanent=self.permanent)
        return self.session_class(sid=sid, permanent=self.permanent)