Concatenate value of two models by overriding ModelForm and ModelChoiceField - django

To show just the just the related Projects in a ForeignKey Selectbox in Django AdminForm, i customized my ActionAdmin Model with a ActionAdminForm class. to preselect values i used a class like posted here https://stackoverflow.com/a/9191583/326905. Thanks a lot, this works really fine.
But when user does not navigate form Customer -> Project -> Action and navigates directly to Actions in django admin i want to display the values in the selectbox for foreignkey project in ActionAdmin Form formatted like this:
Customername1 - Projectname1
Customername1 - Projectname2
Customername2 - Projectname3
My question is, how could i override self.fields["project"]
in the else case in the code below, so that i get selectbox values concatenated from Project.customer.name and Project.name?
class ActionAdminForm(ModelForm):
def __init__(self, *args, **kwargs):
self.request = kwargs.pop('request', None)
super(ActionAdminForm, self).__init__(*args, **kwargs)
if self.request.GET.get('project'):
prj = Project.objects.get(id=self.request.GET.get('project'))
self.fields["project"].queryset = Project.objects.filter(customer = prj.customer)
else:
self.fields["project"] = ProjectModelChoiceField(Project.objects.all().order_by('name'))
class Meta:
model = Action

I got the solution. Yeah. First i got always error when i tried to use just self.fields["project"], but now it works. I put it into else and wrote a ProjectModelChoiceField like below, influenced by this description: http://bradmontgomery.blogspot.de/2009/01/custom-form-for-djangos-automatic-admin.html
class ProjectModelChoiceField(ModelChoiceField):
def label_from_instance(self, obj):
return "%s - %s"%(obj.customer.name, obj.name)

Related

How to display a custom field only in change view (admin)

I'm totally new in Python and Django :) and i need some help.
What i want to do:
I have a model Page and i need to add a custom field "message" when someone try to update one object.
Why? Because i'm building a revision system. This field, it's just an explanation about the change. So this field is not linked to the Page (but to another model PageRevision)
After some research i managed to add this field to my form in the admin.py file, like this:
class PageAdminForm(forms.ModelForm):
# custom field not backed by database
message = forms.CharField(required=False)
class Meta:
model = Page
it's working, my field is now displayed...But i don't want this field everywhere. Just when someone try to update a Page object.
i have found this answer different-fields-for-add-and-change-pages-in-admin but it's not working for me because it's a custom field (i think).
The rest of my code in admin.py:
class PageAdmin(admin.ModelAdmin):
form = PageAdminForm
fields = ["title", "weight", "description", "message"]
list_display = ["title", "weight", "description"]
list_filter = ["updated_at"]
def get_form(self, request, obj=None, **kwargs):
if obj is None:
# not working ?
kwargs['exclude'] = ['message']
# else:
# kwargs['exclude'] = ['message']
return super(PageAdmin, self).get_form(request, obj, **kwargs)
def save_model(self, request, obj, form, change):
if not obj.id:
obj.author = request.user
obj.modified_by = request.user
wiki_page = obj.save()
# save page in revision table
revision = PageRevision(change=change, obj=wiki_page,
request=request)
# retrieve value in the custom field
revision.message = form.cleaned_data['message']
revision.save()
def get_form doesn't exclude my custom message field because i think it doesn't know is existence. If i put another field like title, it's works.
So how to exclude the custom field from add view ?
Thanks :)
You're right, it won't work this way, because 'message' is not a field found on the Page model and the ModelAdmin class will ignore the exclusion. You can achieve this in many ways, but I think the best way to do it is this:
class PageAdmin(admin.ModelAmin):
change_form = PageAdminForm
...
def get_form(self, request, obj=None, **kwargs):
if obj is not None:
kwargs['form'] = self.change_form
return super(UserAdmin, self).get_form(request, obj, **defaults)
Basicaly here django will use an auto-generated ModelForm when adding a Page and your custom form when editing the Page. Django itself uses a similar technique to display different forms when adding and changing a User:
https://github.com/django/django/blob/stable/1.6.x/django/contrib/auth/admin.py (the interesting part is in line 68)
I just stumbled upon this same question and, since it comes in the first search results I would like to add this other solution for people that do not want to use a custom form.
You can override the get_fields method of your admin class to remove a custom field from the Add page.
def get_fields(self, request, obj=None):
fields = list(super().get_fields(request, obj=obj))
if obj is None:
fields.remove("message")
return fields

trying to get request.user, and then a query, in a form that overrides ModelChoiceField and is subclassed

I need to pass an instance variable (self.rank) to be used by a class variable (provider) (see the commented out line below).
Commented out, the code below works. But I'm pretty sure I shouldn't be trying to pass an instance variable up to a class variable anyway. So I'm dumbfounded as to how to accomplish my goal, which is to dynamically filter down my data in the ModelChoiceField.
As you can see, I already overrided ModelChoiceField so I could beautify the usernames. And I also subclassed my basic SwapForm because I have several other forms I'm using (not shown here).
Another way of saying what I need ... I want the value of request.user in my Form so I can then determine the rank of that user and then filter out my Users by rank to build a smaller ModelChoiceField (that looks good too). Note that in my views.py, I call the form using:
form = NewSwapForm(request.user)
or
form = NewSwapForm(request.user, request.POST)
In forms.py:
from myapp.swaps.models import Swaps
from django.contrib.auth.models import User
class UserModelChoiceField(forms.ModelChoiceField):
""" Override the ModelChoiceField to display friendlier name """
def label_from_instance(self, obj):
return "%s" % (obj.get_full_name())
class SwapForm(forms.ModelForm):
""" Basic form from Swaps model. See inherited models below. """
class Meta:
model = Swaps
class NewSwapForm(SwapForm):
# Using a custom argument 'user'
def __init__(self, user, *args, **kwargs):
super(NewSwapForm, self).__init__(*args, **kwargs)
self.rank = User.objects.get(id=user.id).firefighter_rank_set.get().rank
provider = UserModelChoiceField(User.objects.all().
order_by('last_name').
filter(firefighter__hirestatus='active')
### .filter(firefighter_rank__rank=self.rank) ###
)
class Meta(SwapForm.Meta):
model = Swaps
fields = ['provider', 'date_swapped', 'swap_shift']
Thanks!
You can't do it that way, because self doesn't exist at that point - and even if you could, that would be executed at define time, so the rank would be static for all instantiations of the form.
Instead, do it in __init__:
provider = UserModelChoiceField(User.objects.none())
def __init__(self, user, *args, **kwargs):
super(NewSwapForm, self).__init__(*args, **kwargs)
rank = User.objects.get(id=user.id).firefighter_rank_set.get().rank # ??
self.fields['provider'].queryset = User.objects.order_by('last_name').filter(
firefighter__hirestatus='active', firefighter_rank__rank=rank)
I've put a question mark next to the rank line, because rank_set.get() isn't valid... not sure what you meant there.

adding new form fields dynamically in admin

I am trying to add dynamically new form fields (I used this blog post), for a form used in admin interface :
class ServiceRoleAssignmentForm(forms.ModelForm):
class Meta:
model = ServiceRoleAssignment
def __init__(self, *args, **kwargs):
super(ServiceRoleAssignmentForm, self).__init__(*args, **kwargs)
self.fields['test'] = forms.CharField(label='test')
class ServiceRoleAssignmentAdmin(admin.ModelAdmin):
form = ServiceRoleAssignmentForm
admin.site.register(ServiceRoleAssignment, ServiceRoleAssignmentAdmin)
However, no matter what I try, the field doesn't appear on my admin form ! Could it be a problem related to the way admin works ? Or to ModelForm ?
Thank for any help !
Sébastien
PS : I am using django 1.3
When rendering your form in template, fields enumerating from fieldsets variable, not from fields. Sure you can redefine fieldsets in your AdminForm, but then validations will fail as original form class doesn't have such field. One workaround I can propose is to define this field in form definition statically and then redefine that field in form's init method dynamically. Here is an example:
class ServiceRoleAssignmentForm(forms.ModelForm):
test = forms.Field()
class Meta:
model = ServiceRoleAssignment
def __init__(self, *args, **kwargs):
super(ServiceRoleAssignmentForm, self).__init__(*args, **kwargs)
# Here we will redefine our test field.
self.fields['test'] = forms.CharField(label='test2')
I actually have a the same issue which I'm working through at the moment.
While not ideal, I have found a temporary workaround that works for my use case. It might be of use to you?
In my case I have a static name for the field, so I just declared it in my ModelForm. as normal, I then override the init() as normal to override some options.
ie:
def statemachine_form(for_model=None):
"""
Factory function to create a special case form
"""
class _StateMachineBaseModelForm(forms.ModelForm):
_sm_action = forms.ChoiceField(choices=[], label="Take Action")
class Meta:
model = for_model
def __init__(self, *args, **kwargs):
super(_StateMachineBaseModelForm, self).__init__(*args, **kwargs)
actions = (('', '-----------'),)
for action in self.instance.sm_state_actions():
actions += ((action, action),)
self.fields['_sm_action'] = forms.ChoiceField(choices=actions,
label="Take Action")
if for_model: return _StateMachineBaseModelForm
class ContentItemAdmin(admin.ModelAdmin):
form = statemachine_form(for_model=ContentItem)
Now as I mentioned before, this is not entirely 'dynamic', but this will do for me for the time being.
I have the exact same problem that, if I add the field dynamically, without declaring it first, then it doesn't actually exist. I think this does in fact have something to do with the way that ModelForm creates the fields.
I'm hoping someone else can give us some more info.
Django - Overriding get_form to customize admin forms based on request
Try to add the field before calling the super.init:
def __init__(self, *args, **kwargs):
self.fields['test'] = forms.CharField(label='test')
super(ServiceRoleAssignmentForm, self).__init__(*args, **kwargs)

Dynamic choices for Django SelectMultiple Widget

I'm building a form (not modelForm) where i'd like to use the SelectMultiple Widget to display choices based on a query done during the init of the form.
I can think of a few way to do this but I am not exactly clear on the right way to do it. I see different options.
I get the "choices" I should pass to the widget in the form init but I am not sure how I should pass them.
class NavigatorExportForm(forms.Form):
def __init__(self,user, app_id, *args,**kwargs):
super (NavigatorExportForm,self ).__init__(*args,**kwargs) # populates the form
language_choices = Navigator.admin_objects.get(id=app_id).languages.all().values_list('language', flat=True)
languages = forms.CharField(max_length=2, widget=forms.SelectMultiple(choices=???language_choices))
Why not use a ModelMultipleChoiceField instead?
You could do simply this :
class NavigatorExportForm(forms.Form):
languages = forms.ModelMultipleChoiceField(queryset=Language.objects.all())
def __init__(self, app_id, *args, **kwargs):
super(NavigatorExportForm, self).__init__(*args, **kwargs)
# Dynamically refine the queryset for the field
self.fields['languages'].queryset = Navigator.admin_objects.get(id=app_id).languages.all()
This way you don't only restrict the choices available on the widget, but also on the field (that gives you data validation).
With this method, the displayed string in the widget would be the result of the __unicode__ method on a Language object. If it's not what you want, you could write the following custom field, as documented in ModelChoiceField reference :
class LanguageMultipleChoiceField(forms.ModelMultipleChoiceField):
def label_from_instance(self, obj):
return obj.language_code # for example, depending on your model
and use this class instead of ModelMultipleChoiceField in your form.
def __init__(self,user, app_id, *args,**kwargs):
super (NavigatorExportForm,self ).__init__(*args,**kwargs)
self.fields['languages'].widget.choices = Navigator.admin_objects.get(id=app_id).languages.all().values_list('language', flat=True)
that seems to do the trick, but even by not specifying a max_length, the widget only display the first letter of the choices...

Readonly fields in the django admin/inline

I use this snippet to show several fields in my admin backend as readonly, but as noticed in the comments, it does not work on stackedinline/tabularinline. Is there any other way to achieve this? I have a list of objects attached to a model and just want to show it in the model's details view without the possibility to change values.
If you are running Django 1.3 or later; there's an attribute named ModelAdmin.readonly_fields which you could use.
InlineModelAdmin inherits from ModelAdmin, so you should be able to use it from your inline subclass.
I've encountered the same problem today. Here is my solution. This is example of read-only field for the ForeignKey value:
class MySelect(forms.Select):
def render(self, name, value, attrs=None, choices=()):
s = Site.objects.get(id=value)
return s.name
class UserProfileInlineForm(forms.ModelForm):
site = forms.ModelChoiceField(queryset=Site.objects.all(), widget=MySelect)
class UserProfileInline(admin.StackedInline):
model = UserProfile
form = UserProfileInlineForm
As is the case with JQuery, it seems you can achieve this by changing an attr called "disabled" (works in my Safari, OK we're now in 2013 :-) ).
Example below:
def get_form(self, request, obj=None, **kwargs):
result = super(<your ModelAdmin class here>, self).get_form(request, obj=obj, **kwargs)
result.base_fields[<the select field you want to disable>].widget.attrs['disabled'] = 'disabled'
return result