从数据库或会话数据填充字段的正确方法是什么? [英] What is the correct way to populate fields from database or session data?

问题描述

当用户登录时，我在会话中存储了一些变量，以供以后使用以填充字段.

I'm storing some variables in the session when the user logs in, to use later to populate a field.

from flask_wtf import Form
from wtforms import SelectField
from flask import session

class InstitutionForm(Form):

    city = session['city']

    city_tuples = [(x, x) for x in city]

    organisation = SelectField(
        'organisation',
        choices=city_tuples
    )


class Institution(View):

    methods = ['POST']

    def dispatch_request(self):

        form = InstitutionForm()
        return render_template(
            'form/institution.html',
            form=form)

当我运行该应用程序时，出现错误在请求上下文之外工作".从会话数据填充此字段的正确方法是什么?

When I run the app I get the error 'working outside of request context'. What is the correct way to populate this field from the session data?

推荐答案

类定义中的代码在导入时执行，而不是在实例化该类时执行.您需要将对 session 的访问权限移至 __ init __ 方法，以便在视图函数中创建表单时可以对其进行访问.

Code in a class definition is executed at import time, not when the class is instantiated. You need to move the access to session to the __init__ method so that it will be accessed when creating a form in a view function.

class Institution(Form):
    organization = SelectField()

    def __init__(self, *args, **kwargs):
        self.organization.kwargs['choices'] = [(x, x) for x in session.get('city', ('not set',))]
        super().__init__(*args, **kwargs)

这适用于需要应用程序或请求上下文的任何内容，例如数据库查询，而不仅仅是 session .

This applies to anything that needs an application or request context, such as a database query, not just the session.

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