I am trying to realize a Class Based ListView which displays a selection of a table set. If the site is requested the first time, the dataset should be displayed. I would prefer a POST submission, but GET is also fine.
That is a problem, which was easy to handle with function based views, however with class based views I have a hard time to get my head around.
My problem is that I get a various number of error, which are caused by my limited understanding of the classed based views. I have read various documentations and I understand views for direct query requests, but as soon as I would like to add a form to the query statement, I run into different error. For the code below, I receive an ValueError: Cannot use None as a query value.
What would be the best practise work flow for a class based ListView depending on form entries (otherwise selecting the whole database)?
This is my sample code:
models.py
class Profile(models.Model):
name = models.CharField(_('Name'), max_length=255)
def __unicode__(self):
return '%name' % {'name': self.name}
@staticmethod
def get_queryset(params):
date_created = params.get('date_created')
keyword = params.get('keyword')
qset = Q(pk__gt = 0)
if keyword:
qset &= Q(title__icontains = keyword)
if date_created:
qset &= Q(date_created__gte = date_created)
return qset
forms.py
class ProfileSearchForm(forms.Form):
name = forms.CharField(required=False)
views.py
class ProfileList(ListView):
model = Profile
form_class = ProfileSearchForm
context_object_name = 'profiles'
template_name = 'pages/profile/list_profiles.html'
profiles = []
def post(self, request, *args, **kwargs):
self.show_results = False
self.object_list = self.get_queryset()
form = form_class(self.request.POST or None)
if form.is_valid():
self.show_results = True
self.profiles = Profile.objects.filter(name__icontains=form.cleaned_data['name'])
else:
self.profiles = Profile.objects.all()
return self.render_to_response(self.get_context_data(object_list=self.object_list, form=form))
def get_context_data(self, **kwargs):
context = super(ProfileList, self).get_context_data(**kwargs)
if not self.profiles:
self.profiles = Profile.objects.all()
context.update({
'profiles': self.profiles
})
return context
Below I added the FBV which does the job. How can I translate this functionality into a CBV? It seems to be so simple in function based views, but not in class based views.
def list_profiles(request):
form_class = ProfileSearchForm
model = Profile
template_name = 'pages/profile/list_profiles.html'
paginate_by = 10
form = form_class(request.POST or None)
if form.is_valid():
profile_list = model.objects.filter(name__icontains=form.cleaned_data['name'])
else:
profile_list = model.objects.all()
paginator = Paginator(profile_list, 10) # Show 10 contacts per page
page = request.GET.get('page')
try:
profiles = paginator.page(page)
except PageNotAnInteger:
profiles = paginator.page(1)
except EmptyPage:
profiles = paginator.page(paginator.num_pages)
return render_to_response(template_name,
{'form': form, 'profiles': suppliers,},
context_instance=RequestContext(request))
I think your goal is trying to filter queryset based on form submission, if so, by using GET :
class ProfileSearchView(ListView)
template_name = '/your/template.html'
model = Person
def get_queryset(self):
try:
name = self.kwargs['name']
except:
name = ''
if (name != ''):
object_list = self.model.objects.filter(name__icontains = name)
else:
object_list = self.model.objects.all()
return object_list
Then all you need to do is write a get method to render template and context.
Maybe not the best approach. By using the code above, you no need define a django form.
Here's how it works : Class based views separates its way to render template, to process form and so on. Like, get handles GET response, post handles POST response, get_queryset and get_object is self explanatory, and so on. The easy way to know what's method available, fire up a shell and type :
from django.views.generic import ListView if you want to know about ListView
and then type dir(ListView). There you can see all the method defined and go visit the source code to understand it. The get_queryset method used to get a queryset. Why not just define it like this, it works too :
class FooView(ListView):
template_name = 'foo.html'
queryset = Photo.objects.all() # or anything
We can do it like above, but we can't do dynamic filtering by using that approach. By using get_queryset we can do dynamic filtering, using any data/value/information we hav, it means we also can use name parameter that is sent by GET, and its available on kwargs, or in this case, on self.kwargs["some_key"] where some_key is any parameter you specified
Well, I think that leaving validation to form is nice idea. Maybe not worth it in this particular case, because it is very simple form - but for sure with more complicated one (and maybe yours will grow also), so I would do something like:
class ProfileList(ListView):
model = Profile
form_class = ProfileSearchForm
context_object_name = 'profiles'
template_name = 'pages/profile/list_profiles.html'
profiles = []
def get_queryset(self):
form = self.form_class(self.request.GET)
if form.is_valid():
return Profile.objects.filter(name__icontains=form.cleaned_data['name'])
return Profile.objects.all()
This is similar to @jasisz 's approach, but simpler.
class ProfileList(ListView):
template_name = 'your_template.html'
model = Profile
def get_queryset(self):
query = self.request.GET.get('q')
if query:
object_list = self.model.objects.filter(name__icontains=query)
else:
object_list = self.model.objects.none()
return object_list
Then all you have to do on the html template is:
<form method='GET'>
<input type='text' name='q' value='{{ request.GET.q }}'>
<input class="button" type='submit' value="Search Profile">
</form>
This has been explained nicely on the generic views topic here Dynamic filtering.
You can do filtering through GET, I don't think you can use POST method for this as ListView is not inherited from edit mixings.
What you can do is:
urls.py
urlpatterns = patterns('',
(r'^search/(\w+)/$', ProfileSearchListView.as_view()),
)
views.py
class ProfileSearchListView(ListView):
model = Profile
context_object_name = 'profiles'
template_name = 'pages/profile/list_profiles.html'
profiles = []
def get_queryset(self):
if len(self.args) > 0:
return Profile.objects.filter(name__icontains=self.args[0])
else:
return Profile.objects.filter()
I think that the error you are getting is because your form doesn't require the name field. So, although the form is valid, the cleaned_data for your name field is empty.
These could be the problematic lines:
if form.is_valid():
self.show_results = True
self.profiles = Profile.objects.filter(name__icontains=form.cleaned_data['name'])
If I were you, I would try changing the line:
self.profiles = Profile.objects.filter(name__icontains=form.cleaned_data['name'])
to this:
self.profiles = Profile.objects.none()
If you stop receiving errors (and your template receives an empty object_list), the problem you have is what I said before: name field not required.
Let us know if this doesn't work!
Search on all fields in model
class SearchListView(ItemsListView):
# Display a Model List page filtered by the search query.
def get_queryset(self):
fields = [m.name for m in super(SearchListView, self).model._meta.fields]
result = super(SearchListView, self).get_queryset()
query = self.request.GET.get('q')
if query:
result = result.filter(
reduce(lambda x, y: x | Q(**{"{}__icontains".format(y): query}), fields, Q())
)
return result
I think you would be better off doing this via get_context_data. Manually create your HTML form and use GET to retrieve this data. An example from something I wrote is below. When you submit the form, you can use the get data to pass back via the context data. This example isn't tailored to your request, but it should help other users.
def get_context_data(self, **kwargs):
context = super(Search, self).get_context_data(**kwargs)
filter_set = Gauges.objects.all()
if self.request.GET.get('gauge_id'):
gauge_id = self.request.GET.get('gauge_id')
filter_set = filter_set.filter(gauge_id=gauge_id)
if self.request.GET.get('type'):
type = self.request.GET.get('type')
filter_set = filter_set.filter(type=type)
if self.request.GET.get('location'):
location = self.request.GET.get('location')
filter_set = filter_set.filter(location=location)
if self.request.GET.get('calibrator'):
calibrator = self.request.GET.get('calibrator')
filter_set = filter_set.filter(calibrator=calibrator)
if self.request.GET.get('next_cal_date'):
next_cal_date = self.request.GET.get('next_cal_date')
filter_set = filter_set.filter(next_cal_date__lte=next_cal_date)
context['gauges'] = filter_set
context['title'] = "Gauges "
context['types'] = Gauge_Types.objects.all()
context['locations'] = Locations.objects.all()
context['calibrators'] = Calibrator.objects.all()
# And so on for more models
return context
来源：https://stackoverflow.com/questions/13416502/django-search-form-in-class-based-listview