KeyError覆盖django ModelAdmin.get_readonly_fields（）

Question

我想重写我的django ModelAdmin中的get_readonly_fields()方法。如果存在某种条件，我想将几​​乎所有的字段作为readonly_fields返回。下面是如何看起来：

from django.contrib import admin 
from cms.admin.placeholderadmin import PlaceholderAdminMixin 

from .models import (Story, StoryCategory, AVAILABLE_STORY, GLOBAL_STORY) 


RESTRICTED_PUB_FIELDS = ('pub_date',) 
RESTRICTED_FIELDS = ( 
    'global_status', 
    'title', 
    'byline', 
    'byline_headshot', 
    'featured_image', 
    'use_featured_image_on_detail_page', 
    'outside_article_box', 
    'has_detail_page', 
    'landing_page_link', 
    'link_text', 
    'global_categories', 
    'initiatives_tags', 
    'stat_text_before', 
    'stat_number', 
    'stat_text_after', 
    'offices', 
    'rural_liscs', 
) 

class StoryAdmin(PlaceholderAdminMixin, admin.ModelAdmin): 
    def get_readonly_fields(self, request, obj=None): 
     if obj and obj.global_status == AVAILABLE_STORY: 
      fields = self.readonly_fields + \ 
       RESTRICTED_PUB_FIELDS + RESTRICTED_FIELDS 
      return fields 
     return self.readonly_fields 

    def change_view(self, request, object_id, extra_context=None): 
     if '_saveasnew' in request.POST: 
      if request.POST['global_status'] == AVAILABLE_STORY: 
       request.POST['global_status'] = GLOBAL_STORY 

     return super(StoryAdmin, self).change_view(
         request, object_id, extra_context=extra_context 
        ) 

    fieldsets = ( 
     ('Publishing Information', { 
      'fields': (
       'status', RESTRICTED_PUB_FIELDS, 'expire_date', 'slug' 
      ) 
     }), 
     (None, {'fields': (
      RESTRICTED_FIELDS, 
      'excerpt', 
      'local_categories', 
      'is_featured', 
     )}), 
    ) 

    [...] 

admin.site.register(Story, StoryAdmin) 

但当get_readonly_fields()条件为真，一个KeyError异常升高 - 不是在Story对象，但在StoryForm。我知道Django动态地为我创建了一个ModelForm，所以我假设我在某个点传递了错误的东西，但我看不到在哪里。我试图做几乎一字不差同样的事情，在这样的回答：https://stackoverflow.com/a/11601613/4846824

以下是完整回溯：

Environment: 

Request Method: GET 
Request URL: http://localhost:8000/communitycenter/stories/story/369/ 

Django Version: 1.7.8 
Python Version: 2.7.10 
Installed Applications: 
('django.contrib.auth', 
'django.contrib.contenttypes', 
'django.contrib.humanize', 
'django.contrib.messages', 
'django.contrib.redirects', 
'django.contrib.sessions', 
'django.contrib.sites', 
'django.contrib.sitemaps', 
'djangocms_admin_style', 
'django.contrib.admin', 
'django.contrib.admindocs', 
'django.contrib.staticfiles', 
'djangocms_text_ckeditor', 
'cms', 
'djangocms_snippet', 
'filer', 
'menus', 
'sekizai', 
'djangocms_link', 
'clear_cache', 
'compressor', 
'constance', 
'constance.backends.database', 
'adminsortable', 
'django_extensions', 
'easy_thumbnails', 
'gunicorn', 
'haystack', 
'memcache_status', 
'mptt', 
'simplejson', 
'tinymce', 
'treebeard', 
'twython', 
'apps.common', 
'apps.charter', 
'apps.submenu', 
'apps.offices', 
'apps.events', 
'apps.microsites', 
'apps.resources', 
'apps.search', 
'apps.stories', 
'apps.plugins', 
'apps.twitter', 
'apps.charter_calculator') 
Installed Middleware: 
('django.middleware.cache.UpdateCacheMiddleware', 
'django.middleware.common.CommonMiddleware', 
'django.contrib.sessions.middleware.SessionMiddleware', 
'django.middleware.csrf.CsrfViewMiddleware', 
'django.contrib.auth.middleware.AuthenticationMiddleware', 
'django.contrib.messages.middleware.MessageMiddleware', 
'django.contrib.redirects.middleware.RedirectFallbackMiddleware', 
'django.middleware.locale.LocaleMiddleware', 
'cms.middleware.page.CurrentPageMiddleware', 
'cms.middleware.user.CurrentUserMiddleware', 
'cms.middleware.toolbar.ToolbarMiddleware', 
'django.middleware.cache.FetchFromCacheMiddleware') 


Traceback: 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response 
    111.      response = wrapped_callback(request, *callback_args, **callback_kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper 
    583.     return self.admin_site.admin_view(view)(*args, **kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view 
    105.      response = view_func(request, *args, **kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func 
    52.   response = view_func(request, *args, **kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner 
    206.    return view(request, *args, **kwargs) 
File "/Users/kedmundson/DEV/lisc/source/apps/stories/admin.py" in change_view 
    46.       request, object_id, extra_context=extra_context 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/contrib/admin/options.py" in change_view 
    1456.   return self.changeform_view(request, object_id, form_url, extra_context) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper 
    29.    return bound_func(*args, **kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view 
    105.      response = view_func(request, *args, **kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func 
    25.     return func.__get__(self, type(self))(*args2, **kwargs2) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/db/transaction.py" in inner 
    394.     return func(*args, **kwargs) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/contrib/admin/options.py" in changeform_view 
    1427.    model_admin=self) 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/contrib/admin/helpers.py" in __init__ 
    36.   } for field_name, dependencies in prepopulated_fields.items()] 
File "/Users/kedmundson/.virtualenvs/lisc/lib/python2.7/site-packages/django/forms/forms.py" in __getitem__ 
    147.     "Key %r not found in '%s'" % (name, self.__class__.__name__)) 

Exception Type: KeyError at /communitycenter/stories/story/369/ 
Exception Value: u"Key 'title' not found in 'StoryForm'" 

Answer 1

啊哈。这个问题是我prepopulated_fields值：

prepopulated_fields = {'slug': ('title',)}

貌似使得title只读使得它无法以预填充slug领域。但是，这与我OK，因为用户必须要变的蛞蝓，所以我说的get_prepopulated_fields()，使得同样的条件检查此重写，因为我有get_readonly_fields()：

def get_prepopulated_fields(self, request, obj=None): 
    if obj and obj.global_status == AVAILABLE_STORY: 
     return {} 
    return self.prepopulated_fields