Flask视图引发TypeError：'bool'对象不可调用

Question

我正在尝试在我的Flask应用程序中调试一个视图，该视图返回500状态，并在回溯中使用错误TypeError: 'bool' object is not callable。该视图从Flask-Login调用login_user然后返回True以指示登录成功。

我调试到app_iter = app(environ, start_response)和app现在是一个值为True而不是Flask应用程序对象的布尔值。

Traceback (most recent call last):
  File "D:\Python27\lib\site-packages\flask\app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "D:\Python27\lib\site-packages\flask\app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "D:\Python27\lib\site-packages\flask\app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "D:\Python27\lib\site-packages\flask\app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "D:\Python27\lib\site-packages\flask\app.py", line 1478, in full_dispatch_request
    response = self.make_response(rv)
  File "D:\Python27\lib\site-packages\flask\app.py", line 1577, in make_response
    rv = self.response_class.force_type(rv, request.environ)
  File "D:\Python27\lib\site-packages\werkzeug\wrappers.py", line 824, in force_type
    response = BaseResponse(*_run_wsgi_app(response, environ))
  File "D:\Python27\lib\site-packages\werkzeug\wrappers.py", line 57, in _run_wsgi_app
    return _run_wsgi_app(*args)
  File "D:\Python27\lib\site-packages\werkzeug\test.py", line 854, in run_wsgi_app
    app_iter = app(environ, start_response)
TypeError: 'bool' object is not callable

@app.route('/login', methods=['POST'])
def login():
    username = request.form['username']
    user = User.query.filter_by(username=username).first()

    if user:
        login_user(user)
        return True

    return False

Answer 1

在Flask中，视图必须返回以下内容之一：

• 一个字符串
• 一个Response对象（或子类）
• (string, status, headers)或(string, status)的元组
• 一个有效的WSGI应用程序

Flask测试前3个选项，如果它们不适合，则认为它是第四个。您在某处返回True，而是将其视为WSGI应用程序。

请参阅文档中的About Responses。