Flask返回TypeError：視圖函數未返回有效響應

Question

我是Flask的新手，並嘗試使用flask建立簡單的用戶窗體頁面，並遇到錯誤。 當我嘗試僅渲染純HTML並擴展base.html時，一切工作正常，但是添加宏后，結果如下。 我嘗試了所有事情，但無法獨自解決問題。 有什么提示，我在做什么錯？

[2019-07-09 22:19:39,837] ERROR in app: Exception on / [GET]
Traceback (most recent call last):
  File "path/venv/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "path/venv/lib/python3.6/site-packages/flask/app.py", line 1952, in full_dispatch_request
    return self.finalize_request(rv)
  File "path/venv/lib/python3.6/site-packages/flask/app.py", line 1967, in finalize_request
    response = self.make_response(rv)
  File "path/venv/lib/python3.6/site-packages/flask/app.py", line 2130, in make_response
    " {rv.__class__.__name__}.".format(rv=rv)
TypeError: The view function did not return a valid response. The return type must be a string, dict, tuple, Response instance, or WSGI callable, but it was a UserForm.
127.0.0.1 - - [09/Jul/2019 22:19:39] "GET / HTTP/1.1" 500 -

這是我的Python代碼：

from app import app
from flask import render_template
from flask_wtf import FlaskForm
from wtforms import StringField, TextAreaField, SelectField
from wtforms.validators import InputRequired


@app.route('/', methods=['GET', 'POST'])

class UserForm(FlaskForm):
    prefix = StringField("Prefix", validators=[InputRequired()])
    anrede = StringField("Anrede", validators=[InputRequired()])

def form():
    form = UserForm()
    return render_template('html_one_flask.html', form=form)

我要加載的表格

{% extends "base.html" %}

{% from "render_field.html" import render_field %}
{% block content %}

<div class = "container">
    <div class = "spacer" > </div>
</div>
<div class = "container" id = "data_category">PERSONAL DATEN</div>
<div class = "container">
    <div class = "spacer" > </div>
        <div class="form-group row flex-v-center" id = 1>
            {{ render_field(form.prefix), placeholder = form.prefix.label.text }}
            {{ render_field(form.anrede), placeholder = form.anrede.label.text }}
        </div>
</div>
{% endblock %}

和從另一個文件導入的宏

{% macro render_field(field) %}

<div class = "col-0.75">
    <div class = "spacer_label" > </div>
    <label for="{{ field.name }}">{{ field.label.text }} </label>
</div>
<div class = "col-1">
    {{ field(class_ = "form-control input-sm", **kwargs|safe }}
</div>

{% endmacro %}

Answer 1

您的@app.route應該位於view函數上方，而不是類聲明：

@app.route('/', methods=['GET', 'POST'])
def form():
    ...

Answer 2

您將@ app.route裝飾器放在了黃色的地方