如何调试Flask BuildError

Question

我正在尝试在flask 0.8应用程序中调试BuildError。 尝试呈现多步骤表单的第2部分时，在函数personal_open_account()发生错误。 第1步呈现一个表单，如果经过验证，则执行
return redirect(url_for('personal_open_account', step='2')) 。 也就是说，它调用自身，但是带有一个新的step参数。 第1步成功完成，并且表单已通过验证（我可以看到打印的语句），但是随后我立即收到BuildError：

Traceback (most recent call last):
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/app.py", line 1518, in __call__
    return self.wsgi_app(environ, start_response)
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/app.py", line 1506, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/app.py", line 1504, in wsgi_app
    response = self.full_dispatch_request()
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/app.py", line 1264, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/app.py", line 1262, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/app.py", line 1248, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/sth/dev/sb_flask/sb/views/personal.py", line 333, in personal_open_account
    return redirect(url_for('personal_open_account', step='2'))
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/flask/helpers.py", line 208, in url_for
    return ctx.url_adapter.build(endpoint, values, force_external=external)
  File "/Users/sth/.virtualenvs/sb/lib/python2.7/site-packages/werkzeug/routing.py", line 1605, in build
    raise BuildError(endpoint, values, method)
BuildError: ('personal_open_account', {'step': '2'}, None)  

该函数本身看起来像：

@app.route('/personal/save/<product_type>/<slug>/open-account', methods=['GET', 'POST'])
def personal_open_account(product_type, slug):
...

Answer 1

@app.route('/personal/save/<product_type>/<slug>/open-account'是创建api的错误方法。在这里，您有两个连续的/<product_type>/<slug>/路由器不接受。请尝试改写类似@app.route('/personal/save/<product_type>/slugs/<slug>/open-account'的路由。

Answer 2

从查看代码可以轻松推断出，在随后的调用中没有给出product_id和slug参数。