python - Flask View 引发 TypeError : 'bool' object is not callable

Question

我正在尝试调试我的 Flask 应用程序中的一个 View ，该 View 返回 500 状态，回溯中出现错误 TypeError: 'bool' object is not callable。 View 从 Flask-Login 调用 login_user 然后返回 True 以指示登录成功。

我一直在调试，直到 app_iter = app(environ, start_response) 并且 app 现在是一个值为 True 的 bool 值，而不是Flask 应用程序对象。

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， View 必须返回以下之一:

• 一个字符串
• 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，则假定它是第四个。您在某处返回了 True，它被视为 WSGI 应用程序。

参见 About Responses在文档中。