I have some form fields that I want to include/exclude based on whether or not a certain condition is met. I know how to include and exclude form elements, but I am having difficulty doing it when I want it elements to show based on the outcome of a function.
Here is my form:
class ProfileForm(ModelForm):
# this_team = get Team instance from team.id passed in
# how?
def draft_unlocked(self):
teams = Team.objects.order_by('total_points')
count = 0
for team in teams:
if team.pk == this_team.pk:
break
count += 1
now = datetime.datetime.now().weekday()
if now >= count:
# show driver_one, driver_two, driver_three
else:
# do not show driver_one, driver_two, driver_three
class Meta:
model = Team
What I am trying to accomplish is, based on the standings of total points, a team should not be able to change their driver until their specified day. As in, the last team in the standings can add/drop a driver on Monday, second to last team can add/drop on Tuesday, and so on...
So the first problem -- how do I get the Team instance inside the form itself from the id that was passed in. And, how do I include/exclude based on the result of draft_unlocked().
Or perhaps there is a better way to do all of this?
Thanks a lot everyone.
This is actually fairly straightforward (conditional field settings) - here's a quick example:
from django.forms import Modelform
from django.forms.widgets import HiddenInput
class SomeForm(ModelForm):
def __init__(self, *args, **kwargs):
# call constructor to set up the fields. If you don't do this
# first you can't modify fields.
super(SomeForm, self).__init__(*args, **kwargs)
try:
# make somefunc return something True
# if you can change the driver.
# might make sense in a model?
can_change_driver = self.instance.somefunc()
except AttributeError:
# unbound form, what do you want to do here?
can_change_driver = True # for example?
# if the driver can't be changed, use a input=hidden
# input field.
if not can_change_driver:
self.fields["Drivers"].widget = HiddenInput()
class Meta:
model = SomeModel
So, key points from this:
self.instance represents the bound object, if the form is bound. I believe it is passed in as a named argument, therefore in kwargs, which the parent constructor uses to create self.instance.
You can modify the field properties after you've called the parent constructor.
widgets are how forms are displayed. HiddenInput basically means <input type="hidden" .../>.
There is one limitation; I can tamper with the input to change a value if I modify the submitted POST/GET data. If you don't want this to happen, something to consider is overriding the form's validation (clean()) method. Remember, everything in Django is just objects, which means you can actually modify class objects and add data to them at random (it won't be persisted though). So in your __init__ you could:
self.instance.olddrivers = instance.drivers.all()
Then in your clean method for said form:
def clean(self):
# validate parent. Do this first because this method
# will transform field values into model field values.
# i.e. instance will reflect the form changes.
super(SomeForm, self).clean()
# can we modify drivers?
can_change_driver = self.instance.somefunc()
# either we can change the driver, or if not, we require
# that the two lists are, when sorted, equal (to allow for
# potential non equal ordering of identical elements).
# Wrapped code here for niceness
if (can_change_driver or
(sorted(self.instance.drivers.all()) ==
sorted(self.instance.olddrivers))):
return True
else:
raise ValidationError() # customise this to your liking.
You can do what you need by adding your own init where you can pass in the id when you instantiate the form class:
class ProfileForm(ModelForm):
def __init__(self, team_id, *args, **kwargs):
super(ProfileForm, self).__init__(*args, **kwargs)
this_team = Team.objects.get(pk=team_id)
teams = Team.objects.order_by('total_points')
count = 0
for team in teams:
if team.pk == this_team.pk:
break
count += 1
now = datetime.datetime.now().weekday()
if now >= count:
# show driver_one, driver_two, driver_three
else:
# do not show driver_one, driver_two, driver_three
class Meta:
model = Team
#views.py
def my_view(request, team_id):
profile_form = ProfileForm(team_id, request.POST or None)
#more code here
Hope that helps you out.
Related
I have to models which are connected by a M2M-Field realized by another Class ComponentInModule, so that I can add there the extra information, how often a component is in the module.
class Module(models.Model):
...
component = models.ManyToManyField(Component, through="ComponentInModule")
class Component(models.Model):
...
class ComponentInModule(models.Model):
module = models.ForeignKey(InfrastructureModule, on_delete=models.CASCADE)
component = models.ForeignKey(InfrastructureComponent, on_delete=models.CASCADE)
amount = models.IntegerField(default=1)
Now I am trying to load a Module as a form with its corresponding Components as a formset.
class ComponentForm(ModelForm):
amount = IntegerField()
module = InfrastructureModule.objects.get(id=x)
ComponentFormSet = modelformset_factory(Component, form=ComponentForm, extra=0)
component_formset = ComponentFormSet(queryset=module.get_components())
As you can see my ComponentForm has the extra field for the amount. The question now is, how can I pass the value of amount to the Formset on creation, so that all forms are initialized with the right value? With a single Form it's no problem, because I can just pass the value to the __init__ function of the form and put it into the amount field self.fields["amount"].initial = amount. I tried passing a list of values to the formset with form_kwargs, but then I got the problem, that in the __init__function I dont know which of the values in the list is the right one right now.
Is there any way to do this using formsets? Or is there some other option I am missing how you can include the extra fields from a M2M-relation in a ModelForm?
So I worked it out. I made a custom BaseModelFormSet class:
class BaseCompFormset(BaseModelFormSet):
def get_form_kwargs(self, index):
kwargs = super().get_form_kwargs(index)
amount = kwargs["amount"][index]
return {"amount": amount}
Adjusted the __init__ function of the form:
def __init__(self, *args, **kwargs):
amount = kwargs.pop("amount")
super(ComponentForm, self).__init__(*args, **kwargs)
if self.instance:
self.fields["amount"].initial = amount
And used those to create my modelformset_factory:
amounts = [x.amount for x in module.get_components_in_module()]
ComponentFormSet = modelformset_factory(Component, formset=BaseCompFormset, form=ComponentForm, extra=0)
component_formset = ComponentFormSet(queryset=module.get_components(), form_kwargs={'amount':amounts})
And now succesfully got the forms of the formset with the right initial value for amount!
I have some Django models that look something like this (this isn't my exact code but is a simpler example that has the same structure):
class Player(models.Model):
# Some fields here.
pass
class Team(models.Model):
players = models.ManyToManyField(Player, through='TeamPlayer')
class TeamPlayer(models.Model):
team = models.ForeignKey(Team)
player = models.ForeignKey(Player)
some_other_field = models.BooleanField()
I'm using the through mechanism because I have extra columns on my link table.
My admin classes look something like this (note that I am using an inline admin to add the players):
class TeamPlayerInline(admin.TabularInline):
model = TeamPlayer
max_num = 11
extra = 11
class TeamAdmin(admin.ModelAdmin):
inlines = [TeamPlayerInline]
admin.site.register(Team, TeamAdmin)
The Question: My problem is that in my admin I would like to validate that a team has exactly 11 players. Any fewer should result in an error. How can I do this?
These are the things that I have tried and the reasons why they didn't work:
Validate the number of players in the clean method of the Team model. This doesn't work because the players haven't been saved yet, so for a new object there are always zero players.
Validate the number in the clean_players method of a ModelForm used by the TeamAdmin. This method never gets called. Similar methods for other non-ManyToMany fields do get called.
Validate the number in the clean method of the aforementioned ModelForm. This method gets called but the self.cleaned_data dictionary does not have an entry for 'players'.
Any ideas how I can achieve this type of validation? I'm far from being a Django expert so don't assume that I've necessarily done everything that should be obvious.
You need to set the formset on the TeamPlayerInline. And override the clean method in that form set. For example:
from django.forms.models import BaseInlineFormSet
class TeamPlayerFormset(BaseInlineFormSet):
def clean(self):
"""Check that exactly 11 players are entered."""
super(TeamPlayerFormset, self).clean()
if any(self.errors):
return
count = 0
for cleaned_data in self.cleaned_data:
if cleaned_data and not cleaned_data.get('DELETE', False):
count += 1
if count != 11:
raise forms.ValidationError('You must enter 11 team players.')
class TeamPlayerInline(admin.TabularInline):
model = TeamPlayer
max_num = 11
extra = 11
formset = TeamPlayerFormset
class TeamAdmin(admin.ModelAdmin):
inlines = [TeamPlayerInline]
First of all: I am not able to find out the proper Title of this question.
Anyhow the question is:
I have to fill a form at template and the fields of this form are user dependent. For example you passes integer (integer is not a datatype) as a parameter to the method and it should returns like this:
fileds = forms.IntegerField()
If you pass bool then it should like this:
fields = forms.BooleanField()
So that i can use them to create my form. I tried with this code but it returns into the form of string.
Some.py file:
choices = (('bool','BooleanField()'),
('integer','IntegerField()'))
def choose_field():
option = 'bool' # Here it is hardcoded but in my app it comes from database.
for x in choices:
if x[0]==option:
type = x[1]
a = 'forms'
field = [a,type]
field = ".".join(field)
return field
When i print the field it prints 'forms.BooleanField()'. I also use this return value but it didn't work. Amy solution to this problem?
The simpliest way is to create your form class and include fields for all possible choices to it. Then write a constructor in this class and hide the fields you don't want to appear. The constructor must take a parameter indicating which fields do we need. It can be useful to store this parameter in the form and use it in clean method to correct collected data accordingly to this parameter.
class Your_form(forms.ModelForm):
field_integer = forms.IntegerField()
field_boolean = forms.BooleanField()
def __init__(self, *args, **kwargs):
option = kwargs["option"]
if option == "integer":
field_boolean.widget = field_boolean.hidden_widget()
else:
field_integer.widget = field_integer.hidden_widget()
super(Your_form, self).__init__(*args, **kwargs)
In your controller:
option = 'bool'
form = Your_form(option=option)
For this particular administration page, I'd like to turn the 'current value' (outlined in a red circle) into a link going back to the administration page for this particular object.
But I can't find where to go to make this change. I know that I need to somehow override how this
is displayed but I can't figure it out.
What do I need to override to do what I want?
Admin model definition:
class FirmwareConfigElementsChoiceInline(admin.TabularInline):
model = FirmwareConfigElements
extra = 1
class FirmwareConfigAdmin(admin.ModelAdmin):
save_as = True
list_display = ('name', 'description')
inlines = [FirmwareConfigElementsChoiceInline]
Using Filip's great help I've gotten to this:
class FirmwareConfigElementsForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
klass = FirmwareConfigElementsForm
super(klass, self).__init__(*args, **kwargs)
if self.instance.type == 'incfw':
value = self.instance.value
url = '#' # TODO: get the URL for the value
hyperlink = '%s' % (url, value)
label = self.fields['type'].label.replace(value, hyperlink)
self.fields['type'].label = label
But in the above code, self.fields['type'].label has the contents Type and not Include another FW Config - BASE:IBM-HS22/HS22V as I was expecting.
I've explored it in the debugger but I can't figure out how to get to the particular label that I want to change.
Inline admin models have a template property you can use to supply a custom template. From there, you'll need to modify the code to add the url.
You'll need to provide a custom ModelForm for the FirmwareConfigElements model, which you'll set as the value for the FirmwareConfigElementsChoiceInline.form class attribute.
Here you'll want to override the ModelForm.__init__() instance method to assign a new label for the field you want to override if the form is bound:
class FirmwareConfigElementsForm(models.ModelForm):
def __init__(self, *args, **kwargs):
klass = FirmwareConfigElementsForm
super(klass, self).__init__(*args, **kwargs)
if form.is_bound and 'value' in self.data:
value = self.data['value']
url = '' # TODO: get the URL for the value
hyperlink = '%s' % (url, value)
label = self.fields['type'].label.replace(value, hyperlink)
self.fields['type'].label = label
class FirmwareConfigElementsChoiceInline(admin.TabularInline):
model = FirmwareConfigElements
extra = 1
form = FirmwareConfigElementsForm
Now, if you want the label to change dynamically as the user changes the form data, then it gets a lot uglier and you'll have to resort to referencing JavaScript media and performing the above on the fly.
[Update: Changed question title to be more specific]
Sorry if I didn't make the question very well, I can't figure how to do this:
class WhatEver():
number = model.IntegerField('Just a Field', default=callablefunction)
...
Where callablefunction does this query:
from myproject.app.models import WhatEver
def callablefunction():
no = WhatEver.objects.count()
return no + 1
I want to automatically write the next number, and I don't know how to do it.
I have errors from callablefunction stating that it cannot import the model, and I think there must be an easier way to do this. There's no need even to use this, but I can't figure how to do it with the pk number.
I've googled about this and the only thing I found was to use the save() method for auto incrementing the number... but I wanted to show it in the <textfield> before saving...
What would you do?
Got it! I hope this will help everyone that has any problems making a auto-filled and auto-incrementing field in django. The solution is:
class Cliente(models.Model):
"""This is the client data model, it holds all client information. This
docstring has to be improved."""
def number():
no = Cliente.objects.count()
if no == None:
return 1
else:
return no + 1
clientcode = models.IntegerField(_('Code'), max_length=6, unique=True, \
default=number)
[... here goes the rest of your model ...]
Take in care:
The number function doesn't take any arguments (not even self)
It's written BEFORE everything in the model
This was tested on django 1.2.1
This function will automatically fill the clientcode field with the next number (i.e. If you have 132 clients, when you add the next one the field will be filled with clientcode number 133)
I know that this is absurd for most of the practical situations, since the PK number is also auto-incrementing, but there's no way to autofill or take a practical use for it inside the django admin.
[update: as I stated in my comment, there's a way to use the primary key for this, but it will not fill the field before saving]
Every Django model already has an auto-generated primary key:
id = models.AutoField(primary_key=True)
It seems you are trying to duplicate an already existing behavior, just use the object primary key.
I, too, came across this problem, my instance of it was customer.number which was relative to the customers Store. I was tempted to use something like:
# Don't do this:
class Customer(models.Model):
# store = ...
number = models.IntegerField(default=0)
def save(self, *args, **kwargs):
if self.number == 0:
try:
self.number = self.store.customer_set.count() + 1
else:
self.number = 1
super(Customer, self).save(*args, **kwargs)
The above can cause several problems: Say there were 10 Customers, and I deleted customer number 6. The next customer to be added would be (seemingly) the 10th customer, which would then become a second Customer #10. (This could cause big errors in get() querysets)
What I ended up with was something like:
class Store(models.Model):
customer_number = models.IntegerField(default=1)
class Customer(models.Model):
store = models.ForeignKey(Store)
number = models.IntegerField(default=0)
def save(self, *args, **kwargs):
if self.number == 0:
self.number = self.store.customer_number
self.store.number += 1
self.store.save()
super(Customer, self).save(*args, **kwargs)
PS:
You threw out several times that you wanted this field filled in "before". I imagine you wanted it filled in before saving so that you can access it. To that I would say: this method allows you to access store.customer_number to see the next number to come.
You have errors in code, that's why you can't import it:
from django.db import models
class WhatEver(models.Model):
number = models.IntegerField('Just a Field', default=0)
and Yuval A is right about auto-incrementing: you don't even need to declare such a field. Just use the pk or id, they mean the same unless there's a composite pk in the model:
> w = Whatever(number=10)
> w
<Whatever object>
> w.id
None
> w.save()
> w.id
1
[update] Well, I haven't tried a callable as a default. I think if you fix these errors, it must work.