I have a session var with the name 'foo'.
Now I would like, depending of the value of 'foo' load a specific form and template in my cbv. So I need to put form_class and template_name into a switch case.
Which function is the right place for this? get? get_form? looks like nothing is really the right place for this.
Anyone a suggestion or knows another way? :)
CBV explorer is your friend: http://ccbv.co.uk/projects/Django/1.5/django.views.generic.edit/CreateView/
You need to override
def get_form_class(self):
and
def get_template_names(self):
after asking my FormView CBV change ModelForm per request of very much like this question just without the template changing I found this one and your grate answers
so basically I am going to sum it all up
at first I tested this answer by Denny Crane
class Foo(FormView):
def dispatch(self, request, *args, **kwargs):
self.var = request.session['sessionvar']['var']
if self.var == some_value:
form_class = form1
template_name = template1
elif self.var == another_value:
form_class = form2
template_name = template2
[...]
return super(Foo, self).dispatch(request, *args, **kwargs)
I did needed to override
def get_form_class(self):
and
def get_template_names(self):
for this to work and exactly what I needed JUST WITHOUT THE TEMPLATE part becouse in my situation I would like to keep the same templae
so the combination of that two did work!
however then I sew #Serafeim comment
Be careful - this is not good usage of django! If you don't want to repeat your
conditions in both functions just define a new function that would contain > your
conditions and would return True/False. Now this function could be used from > > both get_form_class and get_template_names :)
i changed everything to
this code only
def get_form_class(self):
self.step = self.request.GET.get('step')
# for now I am getting this with request.get, till I will get the
# grip on session :) my first week on django and web-dev in general
if not self.step:
self.step = 'step1'
self.form_class = FORM[self.step] #FORM = dict{'step#': ModelForm}
return self.form_class
and this is working answer
thanks all
If I would use get_form_class() and get_template_names I would have to repeat in both functions my conditions. That would be redundant. Which is not prefered.
I figured out another solution which is not repeating code fragments.
class Foo(FormView):
def dispatch(self, request, *args, **kwargs):
self.var = request.session['sessionvar']['var']
if self.var == some_value:
form_class = form1
template_name = template1
elif self.var == another_value:
form_class = form2
template_name = template2
[...]
return super(Foo, self).dispatch(request, *args, **kwargs)
Related
I created the FormView below that will dynamically return a form class based on what step in the process that the user is in. I'm having trouble with the get_form method. It returns the correct form class in a get request, but the post request isn't working.
tournament_form_dict = {
'1':TournamentCreationForm,
'2':TournamentDateForm,
'3':TournamentTimeForm,
'4':TournamentLocationForm,
'5':TournamentRestrictionForm,
'6':TournamentSectionForm,
'7':TournamentSectionRestrictionForm,
'8':TournamentSectionRoundForm,}
class CreateTournament(FormView):
template_name = 'events/create_tournament_step.html'
def __init__(self, *args, **kwargs):
form_class = self.get_form()
success_url = self.get_success_url()
super(CreateTournament, self).__init__(*args, **kwargs)
def get_form(self, **kwargs):
if 'step' not in kwargs:
step = '1'
else:
step = kwargs['step']
return tournament_form_dict[step]
def get_success_url(self, **kwargs):
if 'step' not in kwargs:
step = 1
else:
step = int(kwargs['step'])
step += 1
if 'record_id' not in kwargs:
record_id = 0
else:
record_id = int(kwargs['record_id'])
return 'events/tournaments/create/%d/%d/' % (record_id, step)
The post request fails at the django\views\generic\edit.py at the get_form line, which I realize is because I've overwritten it in my FormView:
def post(self, request, *args, **kwargs):
"""
Handle POST requests: instantiate a form instance with the passed
POST variables and then check if it's valid.
"""
form = self.get_form()
if form.is_valid(): …
return self.form_valid(form)
else:
return self.form_invalid(form)
However, when I change the name of my custom get_form method to say gen_form, like so:
def __init__(self, *args, **kwargs):
form_class = self.gen_form()
success_url = self.get_success_url()
super(CreateTournament, self).__init__(*args, **kwargs)
def gen_form(self, **kwargs):
if 'step' not in kwargs:
step = '1'
else:
step = kwargs['step']
return tournament_form_dict[step]
my form class doesn't get processed in the get request and evaluates to None. I'm scratching my head as to why when I override the get_form method, it works, but my own named method doesn't? Does anyone know what the flaw might be?
Django's FormMixin [Django-doc] defines a get_form function [Django-doc]. You here thus basically subclassed the FormView and "patched" the get_form method.
Your attempt with the gen_form does not work, since you only defined local variables, and thus do not make much difference anyway, only the super(..) call will have some side effects. The other commands will keep the CPU busy for some time, but at the end, will only assign a reference to a Form calls to the form_class variable, but since it is local, you will throw it away.
That being said, your function contains some errors. For example the **kwargs will usually contain at most one parameter: form_class. So the steps will not do much. You can access the URL parameters through self.args and self.kwargs, and the querystring parameters through self.request.GET. Furthermore you probably want to patch the get_form_class function anyway, since you return a reference to a class, not, as far as I understand it, a reference to an initilized form.
Constructing URLs through string processing is probably not a good idea either, since if you would (slightly) change the URL pattern, then it is likely you will forget to replace the success_url, and hence you will refer to a path that no longer exists. Using the reverse function is a safer way, since you pass the name of the view, and parameters, and then this function will "calculate" the correct URL. This is basically the mechanism behind the {% url ... %} template tag in Django templates.
A better approach is thus:
from django.urls import reverse
class CreateTournament(FormView):
template_name = 'events/create_tournament_step.html'
def get_form_class(self):
return tournament_form_dict[self.kwargs.get('step', '1')]
def get_success_url(self):
new_step = int(self.kwargs.get('step', 1)) + 1
# use a reverse
return reverse('name_of_view', kwargs={'step': new_step})
I've been working with Django for about 3 months now and feel I'm getting a bit better, working my way up to class based views. On the surface they seem cleaner and easier to understand and in some cases they are. In others, not so much. I am trying to use a simple drop down view via ModelChoiceField and a form. I can get it to work with a function based view as shown below in my views.py file:
def book_by_name(request):
form = BookByName(request.POST or None)
if request.method == 'POST':
if form.is_valid():
book_byname = form.cleaned_data['dropdown']
return HttpResponseRedirect(book_byname.get_absolute_url1())
return render(request,'library/book_list.html',{'form':form})
Here is my form in forms.py:
class BookByName(forms.Form):
dropdown = forms.ModelChoiceField(queryset=Book.objects.none())
def __init__(self, *args, **kwargs):
super(BookByName, self).__init__(*args, **kwargs)
self.fields['dropdown'].widget.attrs['class'] = 'choices1'
self.fields['dropdown'].empty_label = ''
self.fields['dropdown'].queryset = Book.objects.order_by('publisher')
This code works. When I have tried to convert to a Class Based View, that's when the trouble begins. I tried to do something like this in views.py:
class BookByNameView(FormView, View):
form_class = BookByName
initial = { 'Book' : Book }
template_name = 'library/book_list.html'
def get(self, request, *args, **kwargs):
form = self.form_class(initial=self.initial)
return render(request, self.template_name, {'form': form})
def get_success_url(self, *args):
return reverse_lazy('library:book_detail', args = (self.object.id,))
When using this with the same form, I receive an attribute error,
'BookByNameView' object has no attribute 'object'.
I've tried ListView as well and received several other errors along the way. The get_success_url also needs to take in a primary key and I can't figure out how to get that passed in as well. Again, I'm a 3 month Django newbie so please be gentle and thanks in advance for your thoughts and suggestions! I feel like I'm in the ballpark...just can't find my seat! I'm very open to doing this differently, if there's a cleaner/better way to do this!
Based on the latest feedback, it would appear the Class Based View should look like:
class BookNameView(FormView):
form_class = BookName
template_name = 'library/book_list.html'
def get_success_url(self, *args):
return reverse_lazy('library:book_detail')
Is this correct? I ran a test version of this and in response to your question as to why I am using self.object.id at all, I am trying to get the pk from the modelchoicefield that I am using to return the view I am trying to get. This may be where I am getting a bit lost. I am trying to get the detail view from the modelchoicefield dropdown, and return the book that is selected. However, I can't seem to pass the pk to this view successfully.
I updated my code to...
class BookByNameView(FormView, ListView):
model = Book
form_class = BookByName
template_name = 'library/book_list.html'
def get_success_url(self, *args):
return reverse_lazy('library:book_detail')
But now it says error...Reverse for 'book_detail' with no arguments not found.
Why are you using self.object there at all? You used form.cleaned_data in the original view, that's what you should use in the class based version too. Note that the form is passed to form_valid.
Note that you've done lots of other weird things too. Your getmethod is pointless, as is your definition of the initial dict; you should delete them both. Also, FormView already inherits from View, there's no need to have View in your declaration explicitly.
You can override the form_valid() function in FormView to achieve what you want. If the form is valid then it is passed to the form_valid() function.
Try this:
class BookByNameView(FormView):
model = Book
form_class = BookByName
template_name = 'library/book_list.html'
def form_valid(self, form):
bookbyname = form.cleaned_data['dropdown']
return HttpResponseRedirect(bookbyname.get_absolute_url())
I have been combing through the internet for quite some while without finding any solution to this problem.
What I am trying to do...
I have the following models:
class TrackingEventType(models.Model):
required_previous_event = models.ForeignKey(TrackingEventType)
class TrackingEvent(models.Model):
tracking = models.ForeignKey(Tracking)
class Tracking(models.Model):
last_event = models.ForeignKey(TrackingEvent)
Now the main model is Tracking, so my admin for Tracking looks like this:
class TrackingEventInline(admin.TabularInline):
model = TrackingEvent
extra = 0
class TrackingAdmin(admin.ModelAdmin):
inlines = [TrackingEventInline]
That's it for the current setup.
Now my quest:
In the TrackingAdmin, when I add new TrackingEvent inlines, I want to limit the options of TrackingEventType to onlye those, that are allowed to follow on the last TrackingEvent of the Tracking. (Tracking.last_event == TrackingEventType.required_previous_event).
For this, I would need to be able to access the related Tracking on the InlineTrackingEvent, to access the last_event and filter the options for TrackingEventType accordingly.
So I found this: Accessing parent model instance from modelform of admin inline, but when I set up TrackingEventInline accordingly:
class MyFormSet(forms.BaseInlineFormSet):
def _construct_form(self, i, **kwargs):
kwargs['parent_object'] = self.instance
print self.instance
return super(MyFormSet, self)._construct_form(i, **kwargs)
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
print kwargs
self.parent_object = kwargs.pop('parent_object')
super(MyForm, self).__init__(*args, **kwargs)
class TrackingEventInline(admin.TabularInline):
form = MyForm
formset = MyFormSet
model = TrackingEvent
extra = 0
I get a KeyError at /admin/.../tracking/2/change/ 'parent_object' from self.parent_object = kwargs.pop('parent_object')
Does anyone know how to solve this? Am I approaching the problem the wrong way? I guess this would be pretty easy in a custom form in the frontend, but I really want to use the admin, because the whole application is built to be used from the admin, and it would be a hell lot of work to build a custom admin interface just because of this problem :)
Ok, so posting on StackOverflow is always helping to get the problem straight. I was able to put together a solution that works for me.
It includes defining my own Form in a outer function, as well as defining two InlineAdmin objects for TrackingEvent (one for update / edit, one just for insert).
Here's the code:
def create_trackingevent_form(tracking):
"""
"""
class TrackingEventForm(forms.ModelForm):
"""
Form for Tracking Event Inline
"""
def clean(self):
"""
May not be needed anymore, since event type choices are limited when creating new event.
"""
next_eventtype = self.cleaned_data['event_type']
tracking = self.cleaned_data['tracking']
# get last event, this also ensures last_event gets updated everytime the change form for TrackingEvent is loaded
last_eventtype = tracking.set_last_event()
if last_eventtype:
last_eventtype = last_eventtype.event_type
pk = self.instance.pk
insert = pk == None
# check if the event is updated or newly created
if insert:
if next_eventtype.required_previous_event == last_eventtype:
pass
else:
raise forms.ValidationError('"{}" requires "{}" as last event, "{}" found. Possible next events: {}'.format(
next_eventtype,
next_eventtype.required_previous_event,
last_eventtype,
'"%s" ' % ', '.join(map(str, [x.name for x in tracking.next_tracking_eventtype_options()]))
)
)
else:
pass
return self.cleaned_data
def __init__(self, *args, **kwargs):
# You can use the outer function's 'tracking' here
self.parent_object = tracking
super(TrackingEventForm, self).__init__(*args, **kwargs)
self.fields['event_type'].queryset = tracking.next_tracking_eventtype_options()
#self.fields['event_type'].limit_choices_to = tracking.next_tracking_eventtype_options()
return TrackingEventForm
class TrackingEventInline(admin.TabularInline):
#form = MyForm
#formset = MyFormSet
model = TrackingEvent
extra = 0
#readonly_fields = ['datetime', 'event_type', 'note']
def has_add_permission(self, request):
return False
class AddTrackingEventInline(admin.TabularInline):
model = TrackingEvent
extra = 0
def has_change_permission(self, request, obj=None):
return False
def queryset(self, request):
return super(AddTrackingEventInline, self).queryset(request).none()
def get_formset(self, request, obj=None, **kwargs):
if obj:
self.form = create_trackingevent_form(obj)
return super(AddTrackingEventInline, self).get_formset(request, obj, **kwargs)
I hope this helps other people with the same problem.. Some credit to the Stack Overflow threads that helped me come up with this:
Prepopulating inlines based on the parent model in the Django Admin
Limit foreign key choices in select in an inline form in admin
https://docs.djangoproject.com/en/1.9/ref/models/instances/#django.db.models.Model.clean_fields
Please do not hesitate to ask questions if you have any
views.py
class PaginatorView(_LanguageMixin, ListView):
context_object_name = 'concepts'
#some custom functions like _filter_by_first_letter
def get_queryset(self):
# some logic here ...
all_concepts = self._filter_by_letter(self.concepts, letters, startswith)
#letters and startswith are obtained from the logic above
print all_concepts
return all_concepts
def get_context_data(self, **kwargs):
context = super(PaginatorView, self).get_context_data(**kwargs)
print context[self.context_object_name]
context.update({
'letters': [(l[0], self._letter_exists(context[self.context_object_name], l)) for l in self.all_letters],
'letter': self.letter_index,
'get_params': self.request.GET.urlencode(),
})
return context
The print all_concepts statement prints all my concepts correctly. So everything until here works just fine. Then, I return all_concepts.
Shouldn't at this point, all_concepts being added to the context, under the key specified by context_object_name? i.e., context['concepts'] should be populated with all_concepts?
If so,the print statement inside get_context_data prints nothing. Which suggests me that the context was not updated.
When I previously used a DetailView, the get_object function was updating the context referenced by context_object_name correctly.(i.e. context[context_object_name] was populated with the object returned by get_object) Shouldn't get_queryset do the same for the ListView?
_LanguageMixin is also defined in views.py, but it is not so relevant for my problem. Just included it here for you to see
class _LanguageMixin(object):
def dispatch(self, request, *args, **kwargs):
self.langcode = kwargs.pop("langcode")
self.language = get_object_or_404(Language, pk=self.langcode)
return super(_LanguageMixin, self).dispatch(request, *args, **kwargs)
def get_context_data(self, **kwargs):
context = super(_LanguageMixin, self).get_context_data(**kwargs)
context.update({"language": self.language,
"languages": Language.objects.values_list('code',
flat=True)})
return context
[EDIT1]
if instead I do save all_concepts i.e. self.all_concepts=... and then I use self.all_concepts instead of context[self.contex_object_name], everything works fine.
[EDIT2]
I never instantiate the PaginatorView. It's only for extending purposes. Down here you can see how I extend it. self.concepts helps me to find all_concepts in the get_queryset of the parent class(PaginatorView)
class AlphabeticView(PaginatorView):
template_name = "alphabetic_listings.html"
model = Property
def get_queryset(self):
self.concepts = (
self.model.objects.filter(
name='prefLabel',
language__code=self.langcode,
)
.extra(select={'name': 'value',
'id': 'concept_id'},
order_by=['name'])
.values('id', 'name')
)
super(AlphabeticView, self).get_queryset()
The print statement in get_context_data is printing empty because the variable context_object_name is empty. You should try print context[self.context_object_name]
EDIT: In response to your correction, try
print context[self.get_context_object_name(self.get_queryset())]
get_context_object_name docs
EDIT 2: In response to your second edit, the reason its is printing 'None' is because you aren't returning from the get_queryset method of AlphabeticView. Change the last line in that method to
return super(AlphabeticView, self).get_queryset()
I need to change the widget used in the admin, based on the value of the db_field. Here's where I'm trying to step in:
def formfield_for_dbfield(self,db_field,**kwargs):
field = super(MyAdmin, self).formfield_for_dbfield(db_field, **kwargs)
if db_field.name == "my_custom_name":
# how can I check here the value of the object?
I've been trying various combinations in the shell for the past 10 minutes, to no result.
Ok, so here's how I finally did it:
class MyAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
self.object_instance = obj
return super(MyAdmin,self).get_form(request,obj,**kwargs)
After that, everything was easy.