AttributeError：“DeferredAttribute”对象没有属性“rel”

Question

我是 Wagtail 和 Django 的新手，我正在尝试构建一个模型，该模型将从 REST API 中提取数据并将其放入可以在模板上迭代的对象中。但是，在尝试迁移时，我收到此错误：

    related = getattr(model, self.relation_name).rel
AttributeError: 'DeferredAttribute' object has no attribute 'rel'

从我目前收集到的信息来看，它与OFSLOrgWebPage 页面模型中的description 和image 字段有关。以下是相关模型：

from __future__ import absolute_import, unicode_literals

from django.db import models
from django.shortcuts import render
from django.conf import settings

from wagtail.wagtailcore.models import Page, Orderable
from wagtail.wagtailcore.fields import RichTextField, StreamField
from wagtail.wagtailadmin.edit_handlers import FieldPanel, FieldRowPanel, MultiFieldPanel, \
    InlinePanel, StreamFieldPanel
from wagtail.wagtailimages.edit_handlers import ImageChooserPanel
from wagtail.wagtailsearch import index

from wagtail.wagtailcore.blocks import StructBlock, StreamBlock, CharBlock, RichTextBlock, RawHTMLBlock, BooleanBlock
from wagtail.wagtailimages.blocks import ImageChooserBlock
from wagtail.wagtaildocs.blocks import DocumentChooserBlock

from modelcluster.fields import ParentalKey

import datetime
import json
import requests

class OFSLOrgWebPage(Page):

    description = RichTextField(blank=True)
    image = models.ForeignKey(
        'serenity.Images',
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name='+',
        help_text="Council image that appears at the top of the page. Size: 500px x 400px"
    )

    def get_context(self, request):
        context = super(OFSLOrgWebPage, self).get_context(request)
        context['greek_orgs'] = self.greek_bios.objects.child_of(self).live()
        return context

    search_fields = Page.search_fields + [
        index.SearchField('description'),
        index.SearchField('greek_orgs'),
    ]

    content_panels = Page.content_panels + [
        InlinePanel('description', label='Council Description'),
        InlinePanel('image', label='Council Image'),
        InlinePanel('greek_bios'),
    ]

    template = '../templates/ofsl_site/ofsl_org_web_page.html'

    class Meta:
        verbose_name = "OFSL Greek Org Page"


class OFSLGreekBio(Orderable):
    name = models.CharField(max_length=255, blank=True)
    letters = models.CharField(blank=True, max_length=3)
    group_id = models.CharField(max_length=255, blank=True)
    page = ParentalKey(OFSLOrgWebPage, related_name='greek_bios')

    def get_groups(self):
        response = requests.get(
            ('{}/api/v1/groups-search/?legacy_group_id={}?format=json').format(
                settings['API_BASE_URL'],
                int(self.group_id)))

        if response.status_code != 200:
            return ''

        return response.json()['objects']

    panels = [
        FieldPanel('name'),
        FieldPanel('letters'),
        FieldPanel('group_id'),
    ]

    class Meta:
        verbose_name = "Greek Organization"
        verbose_name_plural = "Greek Organizations"

编辑：我正在运行 Django 1.11.4 和 Wagtail 1.13.1

Answer 1

您的content_panels 定义为description 和image 使用了错误的面板类型 - InlinePanel 仅用于子对象关系，例如您的greek_bios。你可能想要这个：

content_panels = Page.content_panels + [
    FieldPanel('description'),
    ImageChooserPanel('image'),
    InlinePanel('greek_bios'),
]

Answer 2

您正在使用 Django 2.0 和不支持它的 Wagtail 版本 - 支持 Django 2.0 的第一个 Wagtail 版本将是 Wagtail 2.0，目前处于测试阶段。

您需要降级到 Django 1.11.x 或 install the Wagtail 2.0 beta release。