I need a widget which can make a foreignkey readonly and also it should display the value related to that field not the id
suppose
Class A(models.Model):
id=models.AutoField(primary_key=True)
name=models.CharField(max_length=200)
def __unicode__(self):
return self.name
Class B(models.Model):
id=models.AutoField(primary_key=True)
name=models.ForeignKey(A)
description=models.CharField(max_length=200)
now when i make 'name' of class B as readonly then in admin it only displays the id corresponding value of that name in Class A.Is there any widget that can make the field as readonly and also display the value not id
As a workaround you can:
1) Add the field name to raw_id_fields attribute of ModelAdmin and then
2) Disable id input box using javascript (leaving intact the value label).
It will do what you're asking about except for security issue (if someone imitates disabled/deleted input box). That can additionally be dealt with for example in clean_name function of a class inherited from ModelForm.
What if i display the value in the help_text.Means I m showing the value in help_text as well as Id
This can be achievd simply
def get_form(self, request, obj=None):
form = super(BAdmin,self).get_form(request, obj)
link = obj.id
pl=A.objects.get(id=obj.name_id)
help_text1 = "%s"%(pl.name)
form.base_fields['name'].help_text = help_text1
return form
The third workaround is to use Django trunk which adds readonly_fields property to ModelAdmin.
Other alternative is to patch your current version of django with this patch: http://code.djangoproject.com/ticket/342
EDIT: I am using django r12204, because later revisions break django-cms application, which is vital for me. I thought that later revisions of django had this, but I had to patch my django installation to show foreign key values not id's. But it seems that this behaviour still persists in django trunk, so here is the patch: http://dpaste.com/hold/147814/
Related
In a Django app, I'm having a model Bet which contains a ManyToMany relation with the User model of Django:
class Bet(models.Model):
...
participants = models.ManyToManyField(User)
User should be able to start new bets using a form. Until now, bets have exactly two participants, one of which is the user who creates the bet himself. That means in the form for the new bet you have to chose exactly one participant. The bet creator is added as participant upon saving of the form data.
I'm using a ModelForm for my NewBetForm:
class NewBetForm(forms.ModelForm):
class Meta:
model = Bet
widgets = {
'participants': forms.Select()
}
def save(self, user):
... # save user as participant
Notice the redefined widget for the participants field which makes sure you can only choose one participant.
However, this gives me a validation error:
Enter a list of values.
I'm not really sure where this comes from. If I look at the POST data in the developer tools, it seems to be exactly the same as if I use the default widget and choose only one participant. However, it seems like the to_python() method of the ManyToManyField has its problems with this data. At least there is no User object created if I enable the Select widget.
I know I could work around this problem by excluding the participants field from the form and define it myself but it would be a lot nicer if the ModelForm's capacities could still be used (after all, it's only a widget change). Maybe I could manipulate the passed data in some way if I knew how.
Can anyone tell me what the problem is exactly and if there is a good way to solve it?
Thanks in advance!
Edit
As suggested in the comments: the (relevant) code of the view.
def new_bet(request):
if request.method == 'POST':
form = NewBetForm(request.POST)
if form.is_valid():
form.save(request.user)
... # success message and redirect
else:
form = NewBetForm()
return render(request, 'bets/new.html', {'form': form})
After digging in the Django code, I can answer my own question.
The problem is that Django's ModelForm maps ManyToManyFields in the model to ModelMultipleChoiceFields of the form. This kind of form field expects the widget object to return a sequence from its value_from_datadict() method. The default widget for ModelMultipleChoiceField (which is SelectMultiple) overrides value_from_datadict() to return a list from the user supplied data. But if I use the Select widget, the default value_from_datadict() method of the superclass is used, which simply returns a string. ModelMultipleChoiceField doesn't like that at all, hence the validation error.
To solutions I could think of:
Overriding the value_from_datadict() of Select either via inheritance or some class decorator.
Handling the m2m field manually by creating a new form field and adjusting the save() method of the ModelForm to save its data in the m2m relation.
The seconds solution seems to be less verbose, so that's what I will be going with.
I don't mean to revive a resolved question but I was working a solution like this and thought I would share my code to help others.
In j0ker's answer he lists two methods to get this to work. I used method 1. In which I borrowed the 'value_from_datadict' method from the SelectMultiple widget.
forms.py
from django.utils.datastructures import MultiValueDict, MergeDict
class M2MSelect(forms.Select):
def value_from_datadict(self, data, files, name):
if isinstance(data, (MultiValueDict, MergeDict)):
return data.getlist(name)
return data.get(name, None)
class WindowsSubnetForm(forms.ModelForm):
port_group = forms.ModelMultipleChoiceField(widget=M2MSelect, required=True, queryset=PortGroup.objects.all())
class Meta:
model = Subnet
The problem is that ManyToMany is the wrong data type for this relationship.
In a sense, the bet itself is the many-to-many relationship. It makes no sense to have the participants as a manytomanyfield. What you need is two ForeignKeys, both to User: one for the creator, one for the other user ('acceptor'?)
You can modify the submitted value before (during) validation in Form.clean_field_name. You could use this method to wrap the select's single value in a list.
class NewBetForm(forms.ModelForm):
class Meta:
model = Bet
widgets = {
'participants': forms.Select()
}
def save(self, user):
... # save user as participant
def clean_participants(self):
data = self.cleaned_data['participants']
return [data]
I'm actually just guessing what the value proivded by the select looks like, so this might need a bit of tweaking, but I think it will work.
Here are the docs.
Inspired by #Ryan Currah I found this to be working out of the box:
class M2MSelect(forms.SelectMultiple):
def render(self, name, value, attrs=None, choices=()):
rendered = super(M2MSelect, self).render(name, value=value, attrs=attrs, choices=choices)
return rendered.replace(u'multiple="multiple"', u'')
The first one of the many to many is displayed and when saved only the selected value is left.
I found an easyer way to do this inspired by #Ryan Currah:
You just have to override "allow_multiple_selected" attribut from SelectMultiple class
class M2MSelect(forms.SelectMultiple):
allow_multiple_selected = False
class NewBetForm(forms.ModelForm):
class Meta:
model = Bet
participants = forms.ModelMultipleChoiceField(widget=M2MSelect, required=True, queryset=User.objects.all())
I altered the User class in "/home/david/django/django/contrib/auth/models.py" as follows to override the string representation for a user in my Django application.
class User(models.Model):
...
def __unicode__(self):
return self.get_profile().full_name()
I had written a function called full_name() in my user profile model to display full names the way I want them to be displayed.
However, after I restart Apache, I find that users in select menus of model forms are still represented by usernames. Why?
Don't try to monkey patch you installation. It really is a bad idea.
You can read here how you can override the way a model choice form field shows its model instances.
In you case it would look something like this:
class UserChoiceField(ModelChoiceField):
def label_from_instance(self, obj):
return obj.get_profile().full_name()
Then use this field in your forms. In a model form you will have to override the default field that is used.
This is how my models look:
class QuestionTagM2M(models.Model):
tag = models.ForeignKey('Tag')
question = models.ForeignKey('Question')
date_added = models.DateTimeField(auto_now_add=True)
class Tag(models.Model):
description = models.CharField(max_length=100, unique=True)
class Question(models.Model):
tags = models.ManyToManyField(Tag, through=QuestionTagM2M, related_name='questions')
All I really wanted to do was add a timestamp when a given manytomany relationship was created. It makes sense, but it also adds a bit of complexity. Apart from removing the .add() functionality [despite the fact that the only field I'm really adding is auto-created so it technically shouldn't interfere with this anymore]. But I can live with that, as I don't mind doing the extra QuestionTagM2M.objects.create(question=,tag=) instead if it means gaining the additional timestamp functionality.
My issue is I really would love to be able to preserve my filter_horizontal javascript widget in the admin. I know the docs say I can use an inline instead, but this is just too unwieldy because there are no additional fields that would actually be in the inline apart from the foreign key to the Tag anyway.
Also, in the larger scheme of my database schema, my Question objects are already displayed as an inline on my admin page, and since Django doesn't support nested inlines in the admin [yet], I have no way of selecting tags for a given question.
Is there any way to override formfield_for_manytomany(self, db_field, request=None, **kwargs) or something similar to allow for my usage of the nifty filter_horizontal widget and the auto creation of the date_added column to the database?
This seems like something that django should be able to do natively as long as you specify that all columns in the intermediate are automatically created (other than the foreign keys) perhaps with auto_created=True? or something of the like
There are ways to do this
As provided by #obsoleter in the comment below : set QuestionTagM2M._meta.auto_created = True and deal w/ syncdb matters.
Dynamically add date_added field to the M2M model of Question model in models.py
class Question(models.Model):
# use auto-created M2M model
tags = models.ManyToMany(Tag, related_name='questions')
# add date_added field to the M2M model
models.DateTimeField(auto_now_add=True).contribute_to_class(
Question.tags.through, 'date_added')
Then you could use it in admin as normal ManyToManyField.
In Python shell, use Question.tags.through to refer the M2M model.
Note, If you don't use South, then syncdb is enough; If you do, South does not like
this way and will not freeze date_added field, you need to manually write migration to add/remove the corresponding column.
Customize ModelAdmin:
Don't define fields inside customized ModelAdmin, only define filter_horizontal. This will bypass the field validation mentioned in Irfan's answer.
Customize formfield_for_dbfield() or formfield_for_manytomany() to make Django admin to use widgets.FilteredSelectMultiple for the tags field.
Customize save_related() method inside your ModelAdmin class, like
def save_related(self, request, form, *args, **kwargs):
tags = form.cleaned_data.pop('tags', ())
question = form.instance
for tag in tags:
QuestionTagM2M.objects.create(tag=tag, question=question)
super(QuestionAdmin, self).save_related(request, form, *args, **kwargs)
Also, you could patch __set__() of the ReverseManyRelatedObjectsDescriptor field descriptor of ManyToManyField for date_added to save M2M instance w/o raise exception.
From https://docs.djangoproject.com/en/dev/ref/contrib/admin/#working-with-many-to-many-intermediary-models
When you specify an intermediary model using the through argument to a ManyToManyField, the admin will not display a widget by default. This is because each instance of that intermediary model requires more information than could be displayed in a single widget, and the layout required for multiple widgets will vary depending on the intermediate model.
However, you can try including the tags field explicitly by using fields = ('tags',) in admin. This will cause this validation exception
'QuestionAdmin.fields' can't include the ManyToManyField field 'tags' because 'tags' manually specifies a 'through' model.
This validation is implemented in https://github.com/django/django/blob/master/django/contrib/admin/validation.py#L256
if isinstance(f, models.ManyToManyField) and not f.rel.through._meta.auto_created:
raise ImproperlyConfigured("'%s.%s' "
"can't include the ManyToManyField field '%s' because "
"'%s' manually specifies a 'through' model." % (
cls.__name__, label, field, field))
I don't think that you can bypass this validation unless you implement your own custom field to be used as ManyToManyField.
The docs may have changed since the previous answers were posted. I took a look at the django docs link that #Irfan mentioned and it seems to be a more straight forward then it used to be.
Add an inline class to your admin.py and set the model to your M2M model
class QuestionTagM2MInline(admin.TabularInline):
model = QuestionTagM2M
extra = 1
set inlines in your admin class to contain the Inline you just defined
class QuestionAdmin(admin.ModelAdmin):
#...other stuff here
inlines = (QuestionTagM2MInline,)
Don't forget to register this admin class
admin.site.register(Question, QuestionAdmin)
After doing the above when I click on a question I have the form to do all the normal edits on it and below that are a list of the elements in my m2m relationship where I can add entries or edit existing ones.
I want to add a text next to a field of the django admin interface.
The warning needs to created at runtime inside a python method. I know python and the django ORM well, but I don't know how to get the text next the field.
The text should be a warning. Raising ValidationError in clean() is not a solution, since
the user can't edit the page any more. It should be just a warning message.
You can use custom ModelForm subclass for the admin, adding help_text attribute for the field in question at its initialization, and style it appropriately.
# forms.py
class YourModelForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(YourModelForm, self).__init__(*args, **kwargs)
self.fields['field_in_question'].help_text = generate_warning()
# admin.py
class YourModelAdmin(admin.ModelAdmin):
form = forms.YourModelForm
# And here you can specify custom CSS / JS which would make
# `help_text` for that particular field look like a warning.
# Or you can make it generic--say, style (and maybe reposition w/js) all tags
# like <span class="warning"> that occur within the help text of any field.
class Media:
css = {"all": ("admin_warning.css", )}
js = ("admin_warning.js", )
If you want to do it in changelist view, you can write in model method, which returns string in format you want, and put name of that method in list_display in admin.
class MyModel(models.Model):
myfield = models.CharField(max_length=100)
def myfield_with_warning(self):
return '%s - %s' % (self.myfield, '<span class="warn">My warning message</p>'
myfield_with_warning.short_description = 'My field verbose name'
myfield_with_warning.allow_tags = True
class MyModelAdmin(models.ModelAdmin):
list_display = ('myfield_with_warning',)
If it's not what you need, write more precisely, where do you want to display warning message.
I think the simplest way would be to override the specific admin page for that model. This is described here in the Django documentation. The template you need to override is probably change_form.html. Within these template displayed object is available in the template variable original.
I would add a method or property to you model, that generates and returns the error message and call this method from the template.
Edit: Have a look at contrib/admin/templates/admin/change_form.html there is a include for includes/fieldset.html that displays the the fields of the admin site. You could put some code there that chckes if the model has some special named attribute and if so it is displayed. You could them simply override that change_form.html for all models with your custom one.
If a django model contains a foreign key field, and if that field is shown in list mode, then it shows up as text, instead of displaying a link to the foreign object.
Is it possible to automatically display all foreign keys as links instead of flat text?
(of course it is possible to do that on a field by field basis, but is there a general method?)
Example:
class Author(models.Model):
...
class Post(models.Model):
author = models.ForeignKey(Author)
Now I choose a ModelAdmin such that the author shows up in list mode:
class PostAdmin(admin.ModelAdmin):
list_display = [..., 'author',...]
Now in list mode, the author field will just use the __unicode__ method of the Author class to display the author. On the top of that I would like a link pointing to the url of the corresponding author in the admin site. Is that possible?
Manual method:
For the sake of completeness, I add the manual method. It would be to add a method author_link in the PostAdmin class:
def author_link(self, item):
return '%s' % (item.id, unicode(item))
author_link.allow_tags = True
That will work for that particular field but that is not what I want. I want a general method to achieve the same effect. (One of the problems is how to figure out automatically the path to an object in the django admin site.)
I was looking for a solution to the same problem and ran across this question... ended up solving it myself. The OP might not be interested anymore but this could still be useful to someone.
from functools import partial
from django.forms import MediaDefiningClass
class ModelAdminWithForeignKeyLinksMetaclass(MediaDefiningClass):
def __getattr__(cls, name):
def foreign_key_link(instance, field):
target = getattr(instance, field)
return u'%s' % (
target._meta.app_label, target._meta.module_name, target.id, unicode(target))
if name[:8] == 'link_to_':
method = partial(foreign_key_link, field=name[8:])
method.__name__ = name[8:]
method.allow_tags = True
setattr(cls, name, method)
return getattr(cls, name)
raise AttributeError
class Book(models.Model):
title = models.CharField()
author = models.ForeignKey(Author)
class BookAdmin(admin.ModelAdmin):
__metaclass__ = ModelAdminWithForeignKeyLinksMetaclass
list_display = ('title', 'link_to_author')
Replace 'partial' with Django's 'curry' if not using python >= 2.5.
I don't think there is a mechanism to do what you want automatically out of the box.
But as far as determining the path to an admin edit page based on the id of an object, all you need are two pieces of information:
a) self.model._meta.app_label
b) self.model._meta.module_name
Then, for instance, to go to the edit page for that model you would do:
'../%s_%s_change/%d' % (self.model._meta.app_label, self.model._meta.module_name, item.id)
Take a look at django.contrib.admin.options.ModelAdmin.get_urls to see how they do it.
I suppose you could have a callable that takes a model name and an id, creates a model of the specified type just to get the label and name (no need to hit the database) and generates the URL a above.
But are you sure you can't get by using inlines? It would make for a better user interface to have all the related components in one page...
Edit:
Inlines (linked to docs) allow an admin interface to display a parent-child relationship in one page instead of breaking it into two.
In the Post/Author example you provided, using inlines would mean that the page for editing Posts would also display an inline form for adding/editing/removing Authors. Much more natural to the end user.
What you can do in your admin list view is create a callable in the Post model that will render a comma separated list of Authors. So you will have your Post list view showing the proper Authors, and you edit the Authors associated to a Post directly in the Post admin interface.
See https://docs.djangoproject.com/en/stable/ref/contrib/admin/#admin-reverse-urls
Example:
from django.utils.html import format_html
def get_admin_change_link(app_label, model_name, obj_id, name):
url = reverse('admin:%s_%s_change' % (app_label, model_name),
args=(obj_id,))
return format_html('%s' % (
url, unicode(name)
))