未在Flask会话中使用Flask-Session扩展名设置密钥

Question

当我连接到我的站点时，出现以下错误：

RuntimeError：会话不可用，因为未设置任何秘密密钥。将应用程序上的secret_key设置为唯一且秘密的内容。

下面是我的服务器代码。

from flask import Flask, session
from flask.ext.session import Session

SESSION_TYPE = 'memcache'

app = Flask(__name__)
sess = Session()

nextId = 0

def verifySessionId():
    global nextId

    if not 'userId' in session:
        session['userId'] = nextId
        nextId += 1
        sessionId = session['userId']
        print ("set userid[" + str(session['userId']) + "]")
    else:
        print ("using already set userid[" + str(session['userId']) + "]")
    sessionId = session.get('userId', None)
    return sessionId

@app.route("/")
def hello():
    userId = verifySessionId()
    print("User id[" + str(userId) + "]")
    return str(userId)

if __name__ == "__main__":
    app.secret_key = 'super secret key'

    sess.init_app(app)

    app.debug = True
    app.run()

如您所见，我确实设置了应用密钥。我究竟做错了什么？

还有其他会话选项吗？

其他信息：在Linux Mint上运行Python 2.7

全贴：

Traceback (most recent call last):
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/sean/code/misc/session/sessiontest.py", line 27, in hello
    userId = verifySessionId()
  File "/home/sean/code/misc/session/sessiontest.py", line 16, in verifySessionId
    session['userId'] = nextId
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/werkzeug/local.py", line 341, in __setitem__
    self._get_current_object()[key] = value
  File "/home/sean/code/misc/hangman/venv/lib/python2.7/site-packages/flask/sessions.py", line 126, in _fail
    raise RuntimeError('the session is unavailable because no secret '
RuntimeError: the session is unavailable because no secret key was set.  Set the secret_key on the application to something unique and secret.

Answer 1

在你的情况下，NullSessionInterface会话实现会引发异常，这是使用Flask-Session时的默认会话类型。这是因为你从未真正将SESSION_TYPE配置提供给Flask；仅在模块中将其设置为全局html" target="_blank">变量是不够的。所述瓶会话快速启动的示例代码并设置一个全局，但随后通过调用使用当前模块作为配置对象app.config.from_object(__name__)。

对于Flask 0.10或更高版本，此默认设置没有太大意义；NullSessionFlask 0.8或0.9可能是有意义的，但是在当前版本中，flask.session.NullSession该类用作错误信号。就你而言，它现在给你错误的错误消息。

将SESSION_TYPE配置选项设置为其他内容。挑一个redis，memcached，filesystem或mongodb，并确保其设置在app.config（直接或通过各种Config.from_*方法）。

为了进行快速测试，将其设置filesystem为最简单。那里有足够的默认配置，无需额外的依赖即可正常工作：

if __name__ == "__main__":
    app.secret_key = 'super secret key'
    app.config['SESSION_TYPE'] = 'filesystem'

    sess.init_app(app)

    app.debug = True
    app.run()

如果你看到此错误并且没有使用Flask-Session，则说明设置密码时出了点问题。如果你正在设置app.config[‘SECRET_KEY’]或app.secret_key处于上述if __name__ == "__main__":防护状态，则出现此错误，则可能是通过将Flask项目作为模块导入的WSGI服务器运行了Flask应用程序，并且该__name__ == "__main__"块永远不会运行。