How to exclude fields from django forms.Form? - python

I guess this is another simple question on django forms that I am struggling to find an answer for.
Say I have the following
class Form1(forms.Form):
a=forms.CharField( label=_("A"),max_length=40)
b=forms.CharField( label=_("B"),max_length=40)
class Form2(forms.Form):
c=forms.CharField( label=_("C"),max_length=40)
d=forms.CharField( label=_("D"),max_length=40)
class Form3(Form1,Form2):
def __init__(self, *args, **kw):
Form1.__init__(self,*args, **kw)
Form2.__init__(self,*args, **kw)
#Here I don't want to have a from Form1
# how can I exclude it so that validation does not bark??
I tried exclude=(a,) in Meta class defined in Form3 but does not work, form validation keeps failing form me.
Thanks in advance

Have you tried:
def __init__(self, *args, **kwargs):
super(Form3, self).__init__(*args, **kwargs)
del self.fields['a']

You can override the field and set it to None
class Form3(Form1,Form2):
a = None
Below is the reference:
https://code.djangoproject.com/ticket/8620#no1

Related

Django class view: __init__

I want to get <Model> value from a URL, and use it as an __init__ parameter in my class.
urls.py
url(r'^(?P<Model>\w+)/foo/$', views.foo.as_view(), name='foo_class'),
views.py
class foo(CreateView):
def __init__(self, **kwargs):
text = kwargs['Model'] # This is not working
text = kwargs.get('Model') # Neither this
Bar(text)
...
Clearly, I'm missing something, or my understanding of URL <> class view is wrong.
You should override dispatch method for such use cases.
class Foo(CreateView):
def dispatch(self, request, *args, **kwargs):
# do something extra here ...
return super(Foo, self).dispatch(request, *args, **kwargs)
For your specific scenario, however, you can directly access self.kwargs as generic views automatically assign them as an instance variable on the view instance.

How to filter model choice field options based on user in django?

Here is my form:
class RecipeForm(forms.Form):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user', None)
super(RecipeForm, self).__init__(*args, **kwargs)
Recipebase_id = forms.ModelChoiceField(queryset=Recipebase.objects.filter(user = self.user))
title = forms.CharField(max_length=500)
instructions = forms.CharField(max_length=500)
I want to filter model choice field based on user as you can see from the filter. But it gives the following error:
name 'self' is not defined
Any suggestions would be highly appreciated.
The self. would work only for objects created from a class. In this case you are not creating one, so it would not work as you would expect.
Instead, you need to override the queryset in the __init__ like this:
class RecipeForm(forms.Form):
Recipebase_id = forms.ModelChoiceField(queryset=Recipebase.objects.none())
def __init__(self, *args, **kwargs):
user = kwargs.pop('user') #Throws an error if user is not present
super(RecipeForm, self).__init__(*args, **kwargs)
qs = Recipebase.objects.filter(user=user)
self.fields['Recipebase_id'].queryset = qs
Another way to achieve the same is to make user a required argument in the form
class RecipeForm(forms.Form):
Recipebase_id = forms.ModelChoiceField(queryset=Recipebase.objects.none())
def __init__(self, user, *args, **kwargs):
super(RecipeForm, self).__init__(*args, **kwargs)
qs = Recipebase.objects.filter(user=user)
self.fields['Recipebase_id'].queryset = qs
And the view code would look like this:
form = RecipeForm(request.POST, user=request.user) #user would be passed in as a kwarg to the form class.
Putting your code starting at "Recipebase_id" at the indentation level you have it causes python to execute it at the time the file is parsed/imported. Self is passed into a method when the class is instantiated and the instance method is called, so at parse time self does not exist.
It's unclear to me if you want the Recipebase_id, title and instructions set in the init method. If you do, indent them to the same level as the lines above it. If not, then you'll need to get the value of user from somewhere other than self.

How to make custom field from django field

I want to make my custom field extend from django foreign key.
class CustomField(models.ForeignKey):
def __init__(self, *args, **kwargs):
self.type=kwargs.pop('type', None)
super(CustomField, self).__init__(*args, **kwargs)
I am using like
CustomField('User', type="test")
This works correctly but i want to hard code model name in my field like this
super(CustomField, self).__init__('User', *args, **kwargs)
so that i can use
CustomField(type="test")
but then i get this error
__init__() got multiple values for keyword argument 'to'
The problem is that your are sending the to parameter used by models.ForeginKey in self and in the 'User' parameter when you make call super(CustomField, self).__init__('User', *args, **kwargs). You can try to do in this way:
class CustomField(models.ForeignKey):
def __init__(self, *args, **kwargs):
kwargs['to'] = 'User'
self.type = kwargs.pop('type', None)
super(CustomField, self).__init__(*args, **kwargs)

How do I override this method on a Django Model Field

I'm trying to modify an existing Django Mezzanine setup to allow me to blog in Markdown. Mezzanine has a "Core" model that has content as an HtmlField which is defined like so:
from django.db.models import TextField
class HtmlField(TextField):
"""
TextField that stores HTML.
"""
def formfield(self, **kwargs):
"""
Apply the class to the widget that will render the field as a
TincyMCE Editor.
"""
formfield = super(HtmlField, self).formfield(**kwargs)
formfield.widget.attrs["class"] = "mceEditor"
return formfield
The problem comes from the widget.attrs["class"] of mceEditor. My thoughts were to monkey patch the Content field on the Blog object
class BlogPost(Displayable, Ownable, Content):
def __init__(self, *args, **kwargs):
super(BlogPost, self).__init__(*args, **kwargs)
self._meta.get_field('content').formfield = XXX
My problems are my python skills aren't up to the task of replacing a bound method with a lambda that calls super.
formfield is called by the admin when it wants to create a field for display on the admin pages, so I need to patch that to make the BlogPost widget objects NOT have the class of mceEditor (I'm trying to leave mceEditor on all the other things)
How do you craft the replacement function? I'm pretty sure I attach it with
setattr(self._meta.get_field('content'), 'formfield', method_i_dont_know_how_to_write)
You could change the used formfield in the admin's method formfield_for_dbfield:
class BlogAdmin(admin.ModelAdmin):
def formfield_for_dbfield(self, db_field, **kwargs):
field = super(BlogAdmin, self).formfield_for_dbfield(db_field, **kwargs)
if db_field.name == 'content':
field.widget = ....
field.widget.attrs['class'] = ...
return field
If you really want to do the monkey-patching, it should be something like that:
class BlogPost(Displayable, Ownable, Content):
def __init__(self, *args, **kwargs):
super(BlogPost, self).__init__(*args, **kwargs)
def formfield_new(self, *args, **kwargs):
# do here what you would like to do
return formfield
instancemethod = type(self._meta.get_field('content').formfield)
self._meta.get_field('content').formfield = instancemethod(formfield_new,
self, BlogPost)
I realize this question was answered several months ago, but just in case anyone else comes across it, Mezzanine now provides the ability to completely modify the WYSIWYG editor field. Take a look a the docs for it here:
http://mezzanine.jupo.org/docs/admin-customization.html#wysiwyg-editor

How do I access the request object or any other variable in a form's clean() method?

I am trying to request.user for a form's clean method, but how can I access the request object? Can I modify the clean method to allow variables input?
The answer by Ber - storing it in threadlocals - is a very bad idea. There's absolutely no reason to do it this way.
A much better way is to override the form's __init__ method to take an extra keyword argument, request. This stores the request in the form, where it's required, and from where you can access it in your clean method.
class MyForm(forms.Form):
def __init__(self, *args, **kwargs):
self.request = kwargs.pop('request', None)
super(MyForm, self).__init__(*args, **kwargs)
def clean(self):
... access the request object via self.request ...
and in your view:
myform = MyForm(request.POST, request=request)
For what it's worth, if you're using Class Based Views, instead of function based views, override get_form_kwargs in your editing view. Example code for a custom CreateView:
from braces.views import LoginRequiredMixin
class MyModelCreateView(LoginRequiredMixin, CreateView):
template_name = 'example/create.html'
model = MyModel
form_class = MyModelForm
success_message = "%(my_object)s added to your site."
def get_form_kwargs(self):
kw = super(MyModelCreateView, self).get_form_kwargs()
kw['request'] = self.request # the trick!
return kw
def form_valid(self):
# do something
The above view code will make request available as one of the keyword arguments to the form's __init__ constructor function. Therefore in your ModelForm do:
class MyModelForm(forms.ModelForm):
class Meta:
model = MyModel
def __init__(self, *args, **kwargs):
# important to "pop" added kwarg before call to parent's constructor
self.request = kwargs.pop('request')
super(MyModelForm, self).__init__(*args, **kwargs)
UPDATED 10/25/2011: I'm now using this with a dynamically created class instead of method, as Django 1.3 displays some weirdness otherwise.
class MyModelAdmin(admin.ModelAdmin):
form = MyCustomForm
def get_form(self, request, obj=None, **kwargs):
ModelForm = super(MyModelAdmin, self).get_form(request, obj, **kwargs)
class ModelFormWithRequest(ModelForm):
def __new__(cls, *args, **kwargs):
kwargs['request'] = request
return ModelForm(*args, **kwargs)
return ModelFormWithRequest
Then override MyCustomForm.__init__ as follows:
class MyCustomForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.request = kwargs.pop('request', None)
super(MyCustomForm, self).__init__(*args, **kwargs)
You can then access the request object from any method of ModelForm with self.request.
The usual aproach is to store the request object in a thread-local reference using a middleware. Then you can access this from anywhere in you app, including the Form.clean() method.
Changing the signature of the Form.clean() method means you have you own, modified version of Django, which may not be what you want.
Thank middleware count look something like this:
import threading
_thread_locals = threading.local()
def get_current_request():
return getattr(_thread_locals, 'request', None)
class ThreadLocals(object):
"""
Middleware that gets various objects from the
request object and saves them in thread local storage.
"""
def process_request(self, request):
_thread_locals.request = request
Register this middleware as described in the Django docs
For Django admin, in Django 1.8
class MyModelAdmin(admin.ModelAdmin):
...
form = RedirectForm
def get_form(self, request, obj=None, **kwargs):
form = super(MyModelAdmin, self).get_form(request, obj=obj, **kwargs)
form.request = request
return form
I ran into this particular problem when customizing the admin. I wanted a certain field to be validated based on the particular admin's credentials.
Since I did not want to modify the view to pass the request as an argument to the form, the following is what I did:
class MyCustomForm(forms.ModelForm):
class Meta:
model = MyModel
def clean(self):
# make use of self.request here
class MyModelAdmin(admin.ModelAdmin):
form = MyCustomForm
def get_form(self, request, obj=None, **kwargs):
ModelForm = super(MyModelAdmin, self).get_form(request, obj=obj, **kwargs)
def form_wrapper(*args, **kwargs):
a = ModelForm(*args, **kwargs)
a.request = request
return a
return form_wrapper
The answer by Daniel Roseman is still the best. However, I would use the first positional argument for the request instead of the keyword argument for a few reasons:
You don't run the risk of overriding a kwarg with the same name
The request is optional which is not right. The request attribute should never be None in this context.
You can cleanly pass the args and kwargs to the parent class without having to modify them.
Lastly, I would use a more unique name to avoid overriding an existing variable. Thus, My modified answer looks like:
class MyForm(forms.Form):
def __init__(self, request, *args, **kwargs):
self._my_request = request
super(MyForm, self).__init__(*args, **kwargs)
def clean(self):
... access the request object via self._my_request ...
You can't always use this method (and its probably bad practice), but if you are only using the form in one view you could scope it inside the view method itself.
def my_view(request):
class ResetForm(forms.Form):
password = forms.CharField(required=True, widget=forms.PasswordInput())
def clean_password(self):
data = self.cleaned_data['password']
if not request.user.check_password(data):
raise forms.ValidationError("The password entered does not match your account password.")
return data
if request.method == 'POST':
form = ResetForm(request.POST, request.FILES)
if form.is_valid():
return HttpResponseRedirect("/")
else:
form = ResetForm()
return render_to_response(request, "reset.html")
fresh cheese from cheesebaker#pypi: django-requestprovider
I have another answer to this question as per your requirement you want to access the user into the clean method of the form.
You can Try this.
View.py
person=User.objects.get(id=person_id)
form=MyForm(request.POST,instance=person)
forms.py
def __init__(self,*arg,**kwargs):
self.instance=kwargs.get('instance',None)
if kwargs['instance'] is not None:
del kwargs['instance']
super(Myform, self).__init__(*args, **kwargs)
Now you can access the self.instance in any clean method in form.py
When you want to access it through "prepared" Django class views like CreateView there's a small trick to know (= the official solution doesn't work out of the box). In your own CreateView you'll have to add code like this:
class MyCreateView(LoginRequiredMixin, CreateView):
form_class = MyOwnForm
template_name = 'my_sample_create.html'
def get_form_kwargs(self):
result = super().get_form_kwargs()
result['request'] = self.request
return result
= in short this is the solution to pass request to your form with Django's Create/Update views.

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