AttributeError：“ _ AppCtxGlobals”对象在Flask中没有属性“ user”

Question

@app.route('/login', methods = ['GET', 'POST'])
@oid.loginhandler
def login():
    if g.user is not None and g.user.is_authenticated():
        return redirect(url_for('index'))
    form = LoginForm()
    if form.validate_on_submit():
        session['remember_me'] = form.remember_me.data
        return oid.try_login(form.openid.data, ask_for = ['nickname', 'email'])
    return render_template('login.html', 
        title = "Sign In",
        form = form,
        providers = app.config['OPENID_PROVIDERS'])

但是，这给了我一个AttributeError，我将在下面粘贴StackTrace。这完全是我从示例来源中粘贴的错误。我确实使用PeeWee代替了SQLAlchemy，但是由于这段代码对数据库没有任何作用，但是我不知道为什么会这样。

有人知道我在这里做错什么吗？

Traceback (most recent call last):
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/flask_openid.py", line 446, in decorated
    return f(*args, **kwargs)
  File "/Users/kramer65/dev/repos/microblog/app/views.py", line 31, in login
    if g.user is not None and g.user.is_authenticated():
  File "/Users/kramer65/dev/repos/microblog/flask/lib/python2.7/site-packages/werkzeug/local.py", line 338, in __getattr__
    return getattr(self._get_current_object(), name)
AttributeError: '_AppCtxGlobals' object has no attribute 'user'

Answer 1

g.user全局
如果你要注意的话，你会记得在登录视图功能中我们检查g.user以确定用户是否已经登录。要实现此目的，我们将使用before_requestFlask中的事件。before_request每次接收到请求时，所有装饰有功能的函数都会在查看函数之前运行。因此，这是设置g.user变量（文件app/views.py）的正确位置：

@app.before_request
def before_request():
    g.user = current_user

这就是全部。在current_user全球是由瓶，登录设置，所以我们只要把复制的g对象有更好的访问。这样，所有请求都可以访问登录的用户，甚至在模板内部也可以。

你的代码显然缺少此before_request处理程序。