I've been pulling from various questions on StackOverflow to try to figure out how to work with ModelMultipleChoiceFields within a form. I almost have a working form that allows users to select languages to translate an article to. I created a form that takes a SourceArticle as the first constructor argument and uses it to specify the queryset for the languages field of my form.
class AddTargetLanguagesForm(forms.Form):
def __init__(self, article=None, *args, **kwargs):
super(AddTargetLanguagesForm, self).__init__(*args, **kwargs)
self.fields['languages'].queryset = Language.objects.exclude(
Q(id = article.language.id) |
Q(id__in=[o.id for o in article.get_target_languages()]) |
Q(code="templates"))
languages = forms.ModelMultipleChoiceField(_("Languages"))
Note that my AddTargetLanguagesForm is not based on a ModelForm, because it is not directly related to any of my model objects.
When I render the form for the first time, it correctly provides me with languages that (a) aren't the source language, (b) aren't already selected, and (c) aren't the special "templates" language. However, when I try to post my form, I get the following error:
AttributeError: 'QueryDict' object has
no attribute 'language'
I assume that this is related to how forms work in Django, but I'm pretty new. Rather than accepting a SourceArticle as the first parameter in my constructor, a QueryDict is placed instead. I assume that this contains the POST params from the request. How do I need to modify my code to allow it to capture the selected languages?
Here is a copy of my view, if it helps you see how I'm using the form.
#login_required
def add_target_languages(request, aid, template_name="wt_articles/add_target_languages.html"):
"""
Adds one or more target language translations to a source article.
"""
content_dict = {}
# Fetch the article
no_match = False
sa_set = SourceArticle.objects.filter(id=aid)
if len(sa_set) < 1:
no_match = True
content_dict['no_match'] = no_match
else:
article = sa_set[0]
content_dict['article'] = article
if request.method == "POST":
target_language_form = AddTargetLanguagesForm(request.POST)
if target_language_form.is_valid():
languages = target_language_form.cleaned_data['languages']
article.add_target_languages(languages)
return HttpResponseRedirect('/articles/list')
else:
target_language_form = AddTargetLanguagesForm(article)
content_dict['target_language_form'] = target_language_form
return render_to_response(template_name, content_dict,
context_instance=RequestContext(request))
This line is your problem:
target_language_form = AddTargetLanguagesForm(request.POST)
That's the standard way of instantiating a form from a POST, but the trouble is that you've rewritten the method signature of AddTargetLanguagesForm.__init__:
def __init__(self, article=None, *args, **kwargs):
so that the first positional argument (after the automatic self), is article. You could change the instantiation, but I prefer to do this:
def __init__(self, *args, **kwargs):
article = kwargs.pop('article', None)
super(AddTargetLanguagesForm, self).__init__(*args, **kwargs)
if article is not None:
...etc...
Related
After two years of experience with Django forms, I ran into the following dilemma related to __init__ method:
I have a Django form definition as follows:
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user')
super(MyForm, self).__init__(*args, **kwargs)
if not MyModel.objects.filter(user = self.user).exists():
self.fields['field_1'].widget = forms.HiddenInput()
self.fields['field_2'].widget.attrs['placeholder'] = 'Enter value'
This code is ok if I initialize the form like this:
my_form = MyForm()
However, the problem arises when I try to save user input in the following way:
my_form = MyForm(request.POST)
My point is that I do not want to waste code execution time for setting placeholder property or deciding upon whether some field should be hidden or not AFTER the user has already submitted form.
My concern is that maybe that's because I misuse __init__ method?
Is there any way to check whether request.POST parameter has been provided? And if yes, is it considered best-practice to perform this check and do thinks like settings placeholder, initial values, etc. only if request.POST is not provided?
You can check self.is_bound; it's only true if data is passed to the form.
However, I really think you're over-optimising here. This will only have a tiny impact on the performance of the code.
I'm new to python and trying to understand how to get a dynamic ModelChoiceField to work. It works fine when I select an object with all but I'm trying to get the dropdown to reflect a user's attribute. Here is my code:
Forms.py
class ViewByMake(forms.Form):
dropdown = forms.ModelChoiceField(queryset=Make.objects.none())
def __init__(self, user, *args, **kwargs):
user = kwargs.pop('user')
super(ViewByMake, self).__init__(*args, **kwargs)
qs = Make.objects.filter(user=user)
self.fields['dropdown'].queryset = qs
self.fields['dropdown'].widget.attrs['class'] = 'choices1'
self.fields['dropdown'].empty_label = ''
Views.py
def view_bymake(request):
form = ViewByMake(request.POST or None, user=request.user)
if request.method == 'POST':
if form.is_valid():
make = form.cleaned_data['dropdown']
return HttpResponseRedirect(make.get_absolute_url1())
return render(request,'make/view_make.html',{'form':form})
This code works fine if I remove all user= references but then only returns the full make objects list which is not what I want. I found a very similar question on StackOverflow, but when I duplicated the code identically, it still doesn't work and it is giving me the following error:
init() got multiple values for argument 'user'
I searched the end of the internet on this topic. I'm open to other ideas if I'm approaching this poorly. I'm trying to basically get a filtered list based on criteria associated with a user's profile. I definitely need the drop down field to be specific to a user based on a profile setting. Thanks for your help in advance. I'm running django 1.11.2 and Python 3.6.1.
This is the updated model which need to include the user attribute which I didn't realize that I had to specify:
class Make(models.Model):
name = models.CharField(max_length=264,unique=True)
user = models.ForeignKey(User,null=True,on_delete=models.CASCADE)
Try with request, send request from form and get request in init method of form
views.py
def view_bymake(request):
form = ViewByMake(request.POST or None, request=request)
forms.py
def __init__(self, user, *args, **kwargs):
self.request = kwargs.pop('request', None)
super(ViewByMake, self).__init__(*args, **kwargs)
qs = Make.objects.filter(user=self.request.user)
self.fields['dropdown'].queryset = qs
self.fields['dropdown'].widget.attrs['class'] = 'choices1'
self.fields['dropdown'].empty_label = ''
The answer to my original question, how do I get user=user to work consists of making sure that your form, view, and model all reference user. I originally had the user reference in the view and the form correct, but I neglected to make sure user= was specified on the model I was referencing. I thought it was built in, but turns out you have to specifically reference it on your model. I'm new at this so it was a learning experience. On to the next challenge!
I have 3 Models:
class FileType(models.Model):
name=models.CharField(max_length=128)
class ManagedFile(models.Model):
type = models.ForeignKey(FileType)
content = models.FileField(upload_to=path_maker)
class Tag(models.Model):
type = models.ForeignKey(FileType)
m_file = models.ForeignKey(ManagedFile)
def clean(self):
if self.m_file is None:
return
if self.type != self.m_file.type:
raise ValidationError("File type does not match Tag type")
When select an m_file for a tag, the m_files type MUST match the Tags type. This is all well and good, but the admin drop down for Tag.m_file shows files of all types, regardless of the Tag's type. This is Confusing to users.
There seem to me a number of ways to filter the drop down statically. So if I wanted to say that we will never let the user see Type.pk=1 in the dropdown, I can to that. But there does not seem to be a way to filter on m_file.Type == Self.Type
It is actually quite easy to create your admin form classes dynamically. Something like this should work:
def tagform_factory(filetype):
class TagForm(forms.ModelForm):
m_file = forms.ModelChoiceField(
queryset=ManagedFile.objects.filter(type=filetype)
)
return TagForm
class TagAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
if obj is not None and obj.type is not None:
kwargs['form'] = tagform_factory(obj.type)
return super(TagAdmin, self).get_form(request, obj, **kwargs)
Note that the get_form method is responsible for building the form class, not the form instance. It is badly named, IMHO.
However, you still need to decide what to do for forms that are used to add new tags, rather than edit existing ones. In that case you do not yet have a type to which you can restrict the dropdown. Maybe there is actually a data modeling problem lurking here? Do you really need the type field on the Tag model? Maybe it should just be removed?
Try overriding formfield_for_foreignkey() in the admin. I'm not 100% it does what you want it to do, but if not it should get you started:
class TagAdmin(admin.ModelAdmin):
...
def formfield_for_foreignkey(self, db_field, request, **kwargs):
kwargs['queryset'] = Tag.objects.filter(type=self.type)
I've just created a forms.models.BaseInlineFormSet to override the default formset for a TabularInline model. I need to evaluate the user's group in formset validation (clean) because some groups must write a number inside a range (0,20).
I'm using django admin to autogenerate the interface.
I've tried getting the request and the user from the kwargs in the init method, but I couldn't get the reference.
This is what I have now:
class OrderInlineFormset(forms.models.BaseInlineFormSet):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user')
super(OrderInlineFormset, self).__init__(*args, **kwargs)
def clean(self):
# get forms that actually have valid data
count = 0
for form in self.forms:
try:
if form.cleaned_data:
count += 1
if self.user.groups.filter(name='Seller').count() == 1:
if form.cleaned_data['discount'] > 20:
raise forms.ValidationError('Not authorized to specify a discount greater than 20%')
except AttributeError:
# annoyingly, if a subform is invalid Django explicity raises
# an AttributeError for cleaned_data
pass
if count < 1:
raise forms.ValidationError('You need to specify at least one item')
class OrderItemInline(admin.TabularInline):
model = OrderItem
formset = OrderInlineFormset
Then I use it as inlines = [OrderItemInline,] in my ModelAdmin.
Unfortunatly self.user is always None so I cannot compare the user group and the filter is not applied. I need to filter it because other groups should be able to specify any discount percent.
How can I do? If you also need the ModelAdmin code I'll publish it (I just avoided to copy the whole code to avoid confusions).
Well, I recognise my code there in your question, so I guess I'd better try and answer it. But I would say first of all that that snippet is really only for validating a minimum number of forms within the formset. Your use case is different - you want to check something within each form. That should be done with validation at the level of the form, not the formset.
That said, the trouble is not actually with the code you've posted, but with the fact that that's only part of it. Obviously, if you want to get the user from the kwargs when the form or formset is initialized, you need to ensure that the user is actually passed into that initialization - which it isn't, by default.
Unfortunately, Django's admin doesn't really give you a proper hook to intercept the initialization itself. But you can cheat by overriding the get_form function and using functools.partial to wrap the form class with the request argument (this code is reasonably untested, but should work):
from functools import partial
class OrderForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.user = kwargs.pop('user')
super(OrderForm, self).__init__(*args, **kwargs)
def clean(self)
if self.user.groups.filter(name='Seller').count() == 1:
if self.cleaned_data['discount'] > 20:
raise forms.ValidationError('Not authorized to specify a discount greater than 20%')
return self.cleaned_data
class MyAdmin(admin.ModelAdmin):
form = OrderForm
def get_form(self, request, obj=None, **kwargs):
form_class = super(MyAdmin, self).get_form(request, obj, **kwargs)
return functools.partial(form_class, user=request.user)
Here's another option without using partials. First override the get_formset method in your TabularInline class.
Assign request.user or what ever extra varaibles you need to be available in the formset as in example below:
class OrderItemInline(admin.TabularInline):
model = OrderItem
formset = OrderInlineFormset
def get_formset(self, request, obj=None, **kwargs):
formset = super(OrderProductsInline, self).get_formset(request, obj, **kwargs)
formset.user = request.user
return formset
Now the user is available in the formset as self.user
class OrderInlineFormset(forms.models.BaseInlineFormSet):
def clean(self):
print(self.user) # is available here
I am writing an Edit form, where some fields already contain data. Example:
class EditForm(forms.Form):
name = forms.CharField(label='Name',
widget=forms.TextInput(),
initial=Client.objects.get(pk=??????)) #how to get the id?
What I did for another form was the following (which does not work for the case of the previous EditForm):
class AddressForm(forms.Form):
address = forms.CharField(...)
def set_id(self, c_id):
self.c_id = c_id
def clean_address(self):
# i am able to use self.c_id here
views.py
form = AddressForm()
form.set_id(request.user.get_profile().id) # which works in the case of AddressForm
So what is the best way to pass an id or a value to the form, and that could be used in all forms for that session/user?
Second: is it right to use initial to fill in the form field the way I am trying to do it?
You need to override the __init__ method for your form, like so:
def __init__(self, *args, **kwargs):
try:
profile = kwargs.pop('profile')
except KeyError:
super(SelectForm, self).__init__(*args, **kwargs)
return
super(SelectForm, self).__init__(*args, **kwargs)
self.fields['people'].queryset = profile.people().order_by('name')
and, obviously, build your form passing the right parameter when needed :)