从会话数据填充选择选项的正确方法是什么？ [英] What is the correct way to populate select choices from session data?

问题描述

  
 
在用户登录时，我在会话中存储了一些变量，以便稍后用来填充字段。 from flask_wtf import表单
从wtforms导入SelectField $ b $来自瓶子导入会话
 $ b $ class InstitutionForm（表单）：
 $ b $ city = session ['city'] 
 
 city_tuples = [（x，x）for x in city] 
 
 organization = SelectField（
'organization'，
 choices = city_tuples 
 
 
 $ b $类别机构（视图）：
 
方法= ['POST'] 
 
 def dispatch_request（self）： 
 $ b $ form = InstitutionForm（）
 return render_template（
 form / institution.html'，
 form = form）
  

运行应用程序时，出现在请求上下文之外工作的错误。从会话数据填充此字段的正确方法是什么？

解决方案

类定义中的代码在导入时执行，不是当类被实例化时。您需要将访问权移动到 session 到 __ init __ 方法中，以便在创建表单时访问（b

















$在session.get（'city'，（'not set'）中为x自定义__init __（self，* args，** kwargs）：
self.organization.kwargs ['choices'] = [（x，x） ，））]
表单.__ init __（self，* args，** kwargs）

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

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)

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?

解决方案

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',))]
        Form.__init__(self, *args, **kwargs)

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

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