嵌套字典的Django模型错误

如何解决嵌套字典的Django模型错误

我是Django的新手，但不是python的新手，我的模型尝试使用一个类（在单独的文件中定义），该类中的数据来自REST API，检索到的数据位于嵌套字典中。该代码将在python中正常运行，但是当我在Django（makemigrations）中尝试时，出现错误：

GetFoundOnSelectItems中的文件“ c：\ blah-blah \ Clone_PR.py”，第20行 值= self._issueEdit [“字段”] [“ customfield_13940”] [“ allowedValues”] TypeError：“ NoneType”对象不可下标

我尝试使用类型提示，但这也不起作用。

models.py

from dal import autocomplete
from django.db import models
from django.contrib import messages
from .Login import jlogin
from .Jira_Constants import ProductionServer,TestServer,StageServer
from .Clone_PR import Issue

jira = None
issue = Issue()

class ClonePrLogin(models.Model):
    username = models.CharField(max_length=30)
    password = models.CharField(max_length=30)

    @classmethod
    def LoginToJira(cls):
        global jira
        jira = jlogin(ProductionServer,cls.username,cls.password)

class PrEntry(models.Model):
    prToClone = models.CharField(max_length=20)

    @classmethod
    def GetIssueAndMeta(cls):
        global issue
        issue.initialize(jira,cls.prToClone)

class ClonePr(models.Model):
    issueKey = issue.issueKey
    issue.GetFoundOnSelectItems()
    foundOnList = issue.foundOnSelectItems
    foundOn = autocomplete.Select2ListChoiceField(choice_list=foundOnList)

Clone_PR.py

from typing import List,Dict

class Issue():
    def __init__(self):
        self.jiraInst = None
        self.issueKey = ''
        self._issue = None
        self._issueEdit = None
        # self._issueEdit = Dict[str,Dict[str,List[Dict[str,str]]]]]
        self.foundOnSelectItems = []

    def initialize(self,jira,prKey):
        self.jiraInst = jira
        self.issueKey = prKey
        self._issue = jira.issue(prKey)
        self._issueEdit = jira.editmeta(prKey)

    def GetFoundOnSelectItems(self):
        values = self._issueEdit["fields"]["customfield_13940"]["allowedValues"]
        items = [x["value"] for x in values]
        self.foundOnSelectItems = items

解决方法

在Django中，运行makemigrations将加载所有模块。您说过您熟悉Python，所以您应该知道该类内部的声明：

class ClonePr(models.Model):
    issueKey = issue.issueKey
    issue.GetFoundOnSelectItems()
    foundOnList = issue.foundOnSelectItems
    foundOn = autocomplete.Select2ListChoiceField(choice_list=foundOnList)

将在模块加载时运行。当时您正在呼叫issue.GetFoundOnSelectItems()，而后者依次呼叫values = self._issueEdit["fields"]["customfield_13940"]["allowedValues"]，除了self._issueEdit = None在上面实例实例Issue的开头带有以下行：issue = Issue()之外。

我高度建议您花一些时间来熟悉Django启动应用程序的方式。这里的模块级和嵌套模型声明都是反模式，将来可能会导致数据问题。