我有两个视图,一个在我尝试在表单无效时添加到POST数据时正常工作,另一个在尝试执行相同操作时给出了“此QueryDict实例是不可变的”错误。我知道这些观点与首先存在的太相似,并计划将它们组合起来......但是我想先了解一下它们中的一个失败的区别。
这种观点很好用:
@login_required
def url_parse(request):
cu = request.user
if request.method == 'POST':
form = UrlBragForm(request.POST, request.FILES)
if form.is_valid():
t = handle_image_upload(form.cleaned_data['image'],cu.pk,'url')
if t:
b = Brag()
b.user = cu
b.image = t
b.url = form.cleaned_data['url']
b.description = form.cleaned_data['brag']
b.active = True
b.timestamp = time.time()
b.save()
tags = parse_tags(form.cleaned_data['brag'])
if tags:
for tg in tags:
b.tags.add(tg)
else:
errors = form._errors.setdefault("image", ErrorList())
errors.append(u"There was an issue with your image. Please try again.")
else:
clean = cleanMessage(request.POST['brag'])
if clean != 'is_clean':
request.POST['brag'] = clean
else:
form = UrlBragForm()
return render_to_response('brag/url_brag.html', {'form':form,}, context_instance=RequestContext(request))
但是当查看无效时,这个视图在尝试使用'clean'数据填充request.POST ['brag']时给了我一个“这个QueryDict实例是不可变的”:
@login_required
def brag_add_image(request):
cu = request.user
if request.method == 'POST':
form = ImageAddBragForm(request.POST, request.FILES)
if form.is_valid():
t = handle_image_upload(form.cleaned_data['image'],cu.pk,'url')
if t:
b = Brag()
b.user = cu
b.image = t
b.description = form.cleaned_data['brag']
b.active = True
b.timestamp = time.time()
b.save()
b.url = 'http://%s%s' % (Site.objects.get_current().domain, reverse('image_display', args=(b.pk,)))
b.save()
tags = parse_tags(form.cleaned_data['brag'])
if tags:
for tg in tags:
b.tags.add(tg)
else:
errors = form._errors.setdefault("image", ErrorList())
errors.append(u"There was an issue with your image. Please try again.")
else:
clean = cleanMessage(request.POST['brag'])
if clean != 'is_clean':
request.POST['brag'] = clean
else:
form = ImageAddBragForm()
return render_to_response('brag/image_brag_add.html', {'form':form,}, context_instance=RequestContext(request))
以下是要求的追溯:
Traceback:
File "site/src/django/django/core/handlers/base.py" in get_response
111. response = callback(request, *callback_args, **callback_kwargs)
File "site/src/django/django/contrib/auth/decorators.py" in _wrapped_view
20. return view_func(request, *args, **kwargs)
File "site/brag/views.py" in brag_add_image
241. request.POST['brag'] = clean
File "site/src/django/django/http/__init__.py" in __setitem__
439. self._assert_mutable()
File "site/src/django/django/http/__init__.py" in _assert_mutable
436. raise AttributeError("This QueryDict instance is immutable")
Exception Type: AttributeError at /brag/brag_add_image/
Exception Value: This QueryDict instance is immutable
答案 0 :(得分:2)
想出来。这是因为我在模板中调用表单的方式。如果将enctype更改为multipart,则不会再出现错误。这绝不是一个修复,你应该看看在表单类而不是视图中执行此操作。但我想弄清楚为什么它以一种方式而不是另一种方式起作用。
<form action="." method="post" class="genForm" enctype="multipart/form-data">
vs
<form action="." method="post" class="genForm">
这似乎可能是Django中的一个错误(为什么不在两种情况下强制执行?)
由于这个答案似乎有些混乱,我在这里是一个更简单的例子,显示了相同的结果:
查看:
def testit(request):
if request.method == "POST":
form = testForm(request.POST, request.FILES)
clean = 'Going to stuff post data with this string'
if form.is_valid():
print 'valid'
request.POST['testOne'] = clean
else:
print 'not valid'
request.POST['testOne'] = clean
else:
form = testForm()
return render_to_response('brag_board/test.html', {'form':form}, context_instance=RequestContext(request))
形式:
class testForm(forms.Form):
testOne = forms.CharField(required=True)
testTwo = forms.CharField(required=True)
提供错误的模板:
<!DOCTYPE html>
<html>
<head>
<title>test</title>
</head>
<body>
<form action="." method="post" class="genForm">
{{ form }}
{% csrf_token %}
<button type="submit" name="action" value="addnewsletter">test</button>
</form>
</body>
</html>
不会出错的模板:
<!DOCTYPE html>
<html>
<head>
<title>test</title>
</head>
<body>
<form action="." method="post" class="genForm" enctype="multipart/form-data">
{{ form }}
{% csrf_token %}
<button type="submit" name="action" value="addnewsletter">test</button>
</form>
</body>
</html>