Flask（六）—— 自定义session

    import uuid
    import json
    from flask.sessions import SessionInterface
    from flask.sessions import SessionMixin
    from itsdangerous import Signer, BadSignature, want_bytes

    class MySession(dict, SessionMixin):
        def __init__(self, initial=None, sid=None):
            self.sid = sid
            self.initial = initial
            super(MySession, self).__init__(initial or ())

        def __setitem__(self, key, value):
            super(MySession, self).__setitem__(key, value)

        def __getitem__(self, item):
            return super(MySession, self).__getitem__(item)

        def __delitem__(self, key):
            super(MySession, self).__delitem__(key)

class MySessionInterface(SessionInterface):
        session_class = MySession
        container = {}

        def __init__(self):
            import redis
            self.redis = redis.Redis()

        def _generate_sid(self):
            return str(uuid.uuid4())

        def _get_signer(self, app):
            if not app.secret_key:
                return None
            return Signer(app.secret_key, salt='flask-session',
                          key_derivation='hmac')

        def open_session(self, app, request):
            """
            程序刚启动时执行，需要返回一个session对象
            """
            sid = request.cookies.get(app.session_cookie_name)
            if not sid:
                sid = self._generate_sid()
                return self.session_class(sid=sid)

            signer = self._get_signer(app)
            try:
                sid_as_bytes = signer.unsign(sid)
                sid = sid_as_bytes.decode()
            except BadSignature:
                sid = self._generate_sid()
                return self.session_class(sid=sid)

            # session保存在redis中
            # val = self.redis.get(sid)
            # session保存在内存中
            val = self.container.get(sid)

            if val is not None:
                try:
                    data = json.loads(val)
                    return self.session_class(data, sid=sid)
                except:
                    return self.session_class(sid=sid)
            return self.session_class(sid=sid)

        def save_session(self, app, session, response):
            """
            程序结束前执行，可以保存session中所有的值
            如：
                保存到resit
                写入到用户cookie
            """
            domain = self.get_cookie_domain(app)
            path = self.get_cookie_path(app)
            httponly = self.get_cookie_httponly(app)
            secure = self.get_cookie_secure(app)
            expires = self.get_expiration_time(app, session)

            val = json.dumps(dict(session))

            # session保存在redis中
            # self.redis.setex(name=session.sid, value=val, time=app.permanent_session_lifetime)
            # session保存在内存中
            self.container.setdefault(session.sid, val)

            session_id = self._get_signer(app).sign(want_bytes(session.sid))

            response.set_cookie(app.session_cookie_name, session_id,
                                expires=expires, httponly=httponly,
                                domain=domain, path=path, secure=secure)

# 使用时，需要先新进行配置：
    from flask import Flask
    from flask import session
    from pro_flask.utils.session import MySessionInterface

    app = Flask(__name__)

    app.secret_key = 'A0Zr98j/3yX R~XHH!jmN]LWX/,?RT'
    app.session_interface = MySessionInterface()


    @app.route('/login.html', methods=['GET', "POST"])
    def login():
        print(session)
        session['user1'] = 'alex'
        session['user2'] = 'alex'
        del session['user2']

        return "内容"


    if __name__ == '__main__':
        app.run()