sel*_*lar 8 django validation django-forms modelform
编辑:虽然这篇文章是Django的ModelForm unique_together验证的副本,但是从ModelForm中删除'exclude'的接受答案是比其他问题中接受的答案更清晰的解决方案.
这是这个问题的后续行动.
如果我没有显式检查clean_title()函数中的unique_together约束,则django会抛出异常:
/ journal/journal/4中的IntegrityError
重复键值违反唯一约束"journal_journal_owner_id_key"
请求方法:POST
请求URL: http:// localhost:8000/journal/journal/4
异常类型:IntegrityError
异常值:重复键值违反唯一约束"journal_journal_owner_id_key"
例外位置:/Library/Python/2.6/site-packages/django/db/backends/util.py执行,第19行
但是我的印象是Django会通过引发ValidationError很好地强制执行这个约束,而不是我需要捕获的异常.
下面是我的代码,附带了一个额外的clean_title()方法,我将其用作解决方法.但我想知道我做错了什么,以致django没有以预期的方式强制执行约束.
谢谢.
型号代码:
class Journal (models.Model):
owner = models.ForeignKey(User, related_name='journals')
title = models.CharField(null=False, max_length=256)
published = models.BooleanField(default=False)
class Meta:
unique_together = ("owner", "title")
def __unicode__(self):
return self.title
表格代码:
class JournalForm (ModelForm):
class Meta:
model = models.Journal
exclude = ('owner',)
html_input = forms.CharField(label=u'Journal Content:', widget=TinyMCE(attrs={'cols':'85', 'rows':'40'}, ), )
def clean_title(self):
title = self.cleaned_data['title']
if self.instance.id:
if models.Journal.objects.filter(owner=self.instance.owner, title=title).exclude(id=self.instance.id).count() > 0:
raise forms.ValidationError(u'You already have a Journal with that title. Please change your title so it is unique.')
else:
if models.Journal.objects.filter(owner=self.instance.owner, title=title).count() > 0:
raise forms.ValidationError(u'You already have a Journal with that title. Please change your title so it is unique.')
return title
查看代码:
def journal (request, id=''):
if not request.user.is_active:
return _handle_login(request)
owner = request.user
try:
if request.method == 'GET':
if '' == id:
form = forms.JournalForm(instance=owner)
return shortcuts.render_to_response('journal/Journal.html', { 'form':form, })
journal = models.Journal.objects.get(id=id)
if request.user.id != journal.owner.id:
return http.HttpResponseForbidden('<h1>Access denied</h1>')
data = {
'title' : journal.title,
'html_input' : _journal_fields_to_HTML(journal.id),
'published' : journal.published
}
form = forms.JournalForm(data, instance=journal)
return shortcuts.render_to_response('journal/Journal.html', { 'form':form, })
elif request.method == 'POST':
if LOGIN_FORM_KEY in request.POST:
return _handle_login(request)
else:
if '' == id:
journal = models.Journal()
journal.owner = owner
else:
journal = models.Journal.objects.get(id=id)
form = forms.JournalForm(data=request.POST, instance=journal)
if form.is_valid():
journal.owner = owner
journal.title = form.cleaned_data['title']
journal.published = form.cleaned_data['published']
journal.save()
if _HTML_to_journal_fields(journal, form.cleaned_data['html_input']):
html_memo = "Save successful."
else:
html_memo = "Unable to save Journal."
return shortcuts.render_to_response('journal/Journal.html', { 'form':form, 'saved':html_memo})
else:
return shortcuts.render_to_response('journal/Journal.html', { 'form':form })
return http.HttpResponseNotAllowed(['GET', 'POST'])
except models.Journal.DoesNotExist:
return http.HttpResponseNotFound('<h1>Requested journal not found</h1>')
更新工作代码: 感谢Daniel Roseman.
型号代码保持与上述相同.
表单代码 - 删除exclude语句和clean_title函数:
class JournalForm (ModelForm):
class Meta:
model = models.Journal
html_input = forms.CharField(label=u'Journal Content:', widget=TinyMCE(attrs={'cols':'85', 'rows':'40'},),)
查看代码 - 添加自定义唯一性错误消息:
def journal (request, id=''):
if not request.user.is_active:
return _handle_login(request)
try:
if '' != id:
journal = models.Journal.objects.get(id=id)
if request.user.id != journal.owner.id:
return http.HttpResponseForbidden('<h1>Access denied</h1>')
if request.method == 'GET':
if '' == id:
form = forms.JournalForm()
else:
form = forms.JournalForm(initial={'html_input':_journal_fields_to_HTML(journal.id)},instance=journal)
return shortcuts.render_to_response('journal/Journal.html', { 'form':form, })
elif request.method == 'POST':
if LOGIN_FORM_KEY in request.POST:
return _handle_login(request)
data = request.POST.copy()
data['owner'] = request.user.id
if '' == id:
form = forms.JournalForm(data)
else:
form = forms.JournalForm(data, instance=journal)
if form.is_valid():
journal = form.save()
if _HTML_to_journal_fields(journal, form.cleaned_data['html_input']):
html_memo = "Save successful."
else:
html_memo = "Unable to save Journal."
return shortcuts.render_to_response('journal/Journal.html', { 'form':form, 'saved':html_memo})
else:
if form.unique_error_message:
err_message = u'You already have a Lab Journal with that title. Please change your title so it is unique.'
else:
err_message = form.errors
return shortcuts.render_to_response('journal/Journal.html', { 'form':form, 'error_message':err_message})
return http.HttpResponseNotAllowed(['GET', 'POST'])
except models.Journal.DoesNotExist:
return http.HttpResponseNotFound('<h1>Requested journal not found</h1>')
麻烦的是你专门排除了唯一检查中涉及的一个字段,Django将不会在这种情况下运行检查 - 参见第_get_unique_checks722行的方法django.db.models.base.
owner我不会排除字段,而是考虑将其从模板中删除,并在实例化时传递的数据上明确设置值:
data = request.POST.copy()
data['owner'] = request.user.id
form = JournalForm(data, instance=journal)
请注意,您并未真正使用此模型的强大功能.您不需要在初始GET上显式设置数据字典 - 事实上,您不应该在data那里传递参数,因为它会触发验证:如果您需要传入与实例不同的值,那么应该使用initial.但大多数时候,只是路过instance就足够了.
而且,在POST上,您再次无需明确设置值:您可以这样做:
journal = form.save()
这将正确更新实例并返回它.