问题
I am trying to write a mixin
for able to save a form partially and resume later.
This is useful when the form is long and user cannot finish in one-sitting. The mixin
code below comes directly from prodjango book by Marty Alchin. I have commented in the code where the error comes which is the POST method
in mixin.
Detailed error description below.
From the traceback, I think the error comes from these two calls self.get_form(form_class)
and get_form_kwargs
. but I have no idea how to fix this.
Here is the view
:
class ArticleCreateView(PendFormMixin, CreateView):
form_class = ArticleForm
model = Article
template_name = "article_create.html"
success_url = '/admin'
Here is the mixin
:
from django.views.generic.edit import FormView
from pend_form.models import PendedForm, PendedValue
from hashlib import md5
class PendFormMixin(object):
form_hash_name = 'form_hash'
pend_button_name = 'pend'
def get_form_kwargs(self):
"""
Returns a dictionary of arguments to pass into the form instantiation.
If resuming a pended form, this will retrieve data from the database.
"""
form_hash = self.kwargs.get(self.form_hash_name)
print "form_hash", form_hash
if form_hash:
import_path = self.get_import_path(self.get_form_class())
return {'data': self.get_pended_data(import_path, form_hash)}
else:
print "called"
# print super(PendFormMixin, self).get_form_kwargs()
return super(PendFormMixin, self).get_form_kwargs()
def post(self, request, *args, **kwargs):
"""
Handles POST requests with form data. If the form was pended, it doesn't follow
the normal flow, but saves the values for later instead.
"""
if self.pend_button_name in self.request.POST:
print "here"
form_class = self.get_form_class()
print form_class
form = self.get_form(form_class)
#the error happens here. below print is not executed
# print "form is ", form
self.form_pended(form)
else:
super(PendFormMixin, self).post(request, *args, **kwargs)
# Custom methods follow
def get_import_path(self, form_class):
return '{0}.{1}'.format(form_class.__module__, form_class.__name__)
def get_form_hash(self, form):
content = ','.join('{0}:{1}'.format(n, form.data[n]) for n in form.fields.keys())
return md5(content).hexdigest()
def form_pended(self, form):
import_path = self.get_import_path(self.get_form_class())
form_hash = self.get_form_hash(form)
print "in form_pended"
pended_form = PendedForm.objects.get_or_create(form_class=import_path,
hash=form_hash)
for name in form.fields.keys():
pended_form.data.get_or_create(name=name, value=form.data[name])
return form_hash
def get_pended_data(self, import_path, form_hash):
data = PendedValue.objects.filter(import_path=import_path, form_hash=form_hash)
return dict((d.name, d.value) for d in data)
Error:
'ArticleCreateView' object has no attribute 'object'
Exception Location: /Users/django/django/lib/python2.7/site-packages/django/views/generic/edit.py in get_form_kwargs, line 125
/Users/pend_form/forms.py in post
form = self.get_form(form_class)
/Users/django/django/lib/python2.7/site-packages/django/views/generic/edit.py in get_form_kwargs
kwargs.update({'instance': self.object})
回答1:
If you look at the definition of django's CreateView
, or its parent BaseCreateView
, you'll see that all it does is assigns self.object = None
before calling super class methods which define the actual form behavior. That's because it's a CreateView
- no object to edit could possibly exist.
Since your mixin overrides this behavior, the rest of the machinery fails when it expects self.object
to exist as None
.
Add self.object = None
to the first line of your def post
method.
回答2:
self.object is assigned in post
, so if you override post
,
don't expect self.object
ot be assigned, before you call super(...).post(...)
来源:https://stackoverflow.com/questions/23774412/attributeerror-myview-has-no-attribute-object-in-custom-mixin-in-django