python - 无法使用 flask.g 访问其他函数中的变量

Question

我正在尝试使用 flask.g 来存储可以在其他函数中访问的变量，但我似乎没有做正确的事情。当我尝试访问 g.name 时，应用程序生成以下错误:AttributeError: '_RequestGlobals' object has no attribute 'name'。

documentation对于 flask.g 说:

Just store on this whatever you want. For example a database connection or the user that is currently logged in.

这是一个完整的最小示例，它说明了我在尝试访问创建它的函数之外的变量时收到的错误。我们将不胜感激任何帮助。

#!/usr/bin/env python

from flask import Flask, render_template_string, request, redirect, url_for, g
from wtforms import Form, TextField

application = app = Flask('wsgi')

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

    if request.method == 'POST' and form.validate():
        name =  form.name.data
        g.name = name

        # Need to create an instance of a class and access that in another route
        #g.api = CustomApi(name)

        return redirect(url_for('get_posts'))

    else:

        return render_template_string(template_form, form=form)

@app.route('/posts', methods=['GET'])
def get_posts():
    # Need to access the instance of CustomApi here
    #api = g.api
    name = g.name
    return render_template_string(name_template, name=name)


class LoginForm(Form):
    name = TextField('Name')

template_form = """
{% block content %}
<h1>Enter your name</h1>

<form method="POST" action="/">
    <div>{{ form.name.label }} {{ form.name() }}</div><br>
    <button type="submit" class="btn">Submit</button>    
</form>
{% endblock %}

"""

name_template = """
{% block content %}

    <div>"Hello {{ name }}"</div><br>

{% endblock %}

"""

if __name__ == '__main__':
    app.run(debug=True)

Answer 1

g 对象是一个基于请求的对象，不会在请求之间持续存在，即 g 在您对 index 的请求和您对 get_posts 的请求。

Application Globals in Flask :

Flask provides you with a special object that ensures it is only valid for the active request and that will return different values for each request. In a nutshell: it does the right thing, like it does for request and session.

要在请求之间持久存储微小数据，请使用 sessions反而。如果您发现这是一个很好的理由。

对于更复杂的数据使用数据库。