In order to be sure I force users to pick a valid value from a dropdown (rather than unknowingly leaving the first option in the list set without changing it to the correct value), I am inserting the blank choice field in many required form fields.
models.py
class MyModel(models.Model):
gender = models.CharField(max_length=1, null=True, blank=False, choices=GENDER_CHOICES, default='')
Original forms.py (Explicitly defining the form field. This works.)
from django.db.models.fields import BLANK_CHOICE_DASH
class MyForm(forms.ModelForm):
gender = forms.TypedChoiceField(required=True, choices=BLANK_CHOICE_DASH+MyModel._meta.get_field('gender').choices)
class Meta:
model = MyModel
fields = '__all__'
Now, because I am doing this for many fields, I tried to revise my earlier code in forms.py:
Revised forms.py (Setting the choices in __init__(). Does not work.)
class MyForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
for type in ('gender', ...):
self.fields[type].choices.insert(0, (u'',u'---------' ))
# Not needed anymore.. replaced by code in __init__()
# gender = forms.TypedChoiceField(required=True, choices=BLANK_CHOICE_DASH+MyModel._meta.get_field('gender').choices)
class Meta:
model = MyModel
fields = '__all__'
In this case, I do not get the dashes as the first choice in the dropdown.
I tried to look into the problem by using pdb in the template to inspect the form field right before it was outputted. The debugger shows element.field.choices to be (u'', u'---------'), ('f', 'Female'), ...] in both cases. Nevertheless, the code that outputs the form field inserts the dashes only in the original code, not in the revised code.
I tried stepping through the Django code that renders the form field to figure out if it was using some other field besides .choices that I'm not aware of, but I never stepped into the right part of the code.
Any ideas how to accomplish this? Although it works fine the first way, the revised code is much DRY-er... if only I could make it work! Thanks!
Related
I'm super new to Django, so bare with me. I'm trying to write a simple CRUD, using modelforms. In the update view, the form object initialization takes the arguments initial and instance, which confuses me. From django doc:
"As with regular forms, it’s possible to specify initial data for forms by specifying an initial parameter when instantiating the form. Initial values provided this way will override both initial values from the form field and values from an attached model instance."
Which confuses even more. I know my question isn't specific, but if someone could explain this and honestly, the background connection between the model and modelforms I would really appreciate it. Thanks y'all
Here is the example from Django docs;
from django.db import models
from django.forms import ModelForm
TITLE_CHOICES = [
('MR', 'Mr.'),
('MRS', 'Mrs.'),
('MS', 'Ms.'),
]
class Author(models.Model):
name = models.CharField(max_length=100)
title = models.CharField(max_length=3, choices=TITLE_CHOICES)
birth_date = models.DateField(blank=True, null=True)
def __str__(self):
return self.name
class AuthorForm(ModelForm):
class Meta:
model = Author
fields = ['name', 'title', 'birth_date']
Your form -AuthorForm has information that name is string and it can't be greater than 100 characters. Because it's in your model -Author. Same for title and birth_date. title can't be greater than 3 characters and it must be one of the MR, MRS or MS.
You don't have to specify types, rules for form fields if you use model forms. Model forms can create forms quickly from your model and makes validations based on your model.
Let's assume you have an author instance which has name is Joe.
If you print author.name, it returns Joe.
form = AuthorForm(initial={'name': 'Patrick'}, instance=author)
If you print form['name'].value(), it returns Patrick, not Joe. It ignores author's name value. You overrided it in your form. It could be Joe if you didn't pass initial parameter.
I have a checkbox choice field like this:
models.py
TYPE_CHOICES = (
('s', 'small'),
('m', 'medium'),
('b', 'big'),
)
class Post(models.Model) :
size = models.CharField(blank=True,max_length="3", choices=TYPE_CHOICES)
So in the admin form:
class MainContent(forms.ModelForm):
size = forms.MultipleChoiceField(choices=TYPE_CHOICES, widget=forms.CheckboxSelectMultiple())
class Meta:
model = Post
fields = '__all__'
But when I saving the form it give me this error:
Select a valid choice. ['s', 'm', 'b'] is not one of the available
choices.
So, what is the problem?
UPDATE
My apology, this question was not given enough info, let me explain more.
The reason I want a checkbox input is because I want it able to store multiple values in the single field (one column). Perhaps the data can be serialized (or comma separated),
Since the TYPE_CHOICES is static and will not changed in the future, I am not planning to use ManytoMany.
Also I want it able to display in the template easily by the language language.
Hope this is clear enough.
Presumably, you want a single column in a table that is storing
multiple values. This will also force you to think about how to will
serialize - for example, you can't simply do comma separated if you
need to store strings that might contain commas.
However, you are best using a solution like one of the following:
https://pypi.python.org/pypi/django-multiselectfield/
https://pypi.python.org/pypi/django-select-multiple-field/
This answer solve your problem, you are try to store a list of strings, but the charfield.
Link to post
or try use ChoiceField
You're using a CharField in your model but in your form you use MultipleChoiceField, for a ModelForm it's an incompatible type because it wouldn't know what to do if the user chooses more than one option, I would recommend using a catalog and a ManyToManyField:
If you want to select more than one size for a Post model:
models.py
class SizesCatalog(models.Model):
description = models.CharField(max_length=255)
def __str__(self):
return self.description
class Post(models.Model) :
size = models.ManyToMany(SizesCatalog, db_table='post_sizes')
admin form
class MainContent(forms.ModelForm):
class Meta:
model = Post
fields = '__all__'
if you want to select just one size for just one:
models.py
class SizesCatalog(models.Model):
description = models.CharField(max_length=255)
def __str__(self):
return self.description
class Post(models.Model) :
size = models.ManyToMany(SizesCatalog)
admin form
class MainContent(forms.ModelForm):
class Meta:
model = Post
fields = '__all__'
That way you let Django deal with your problems and in a future you could even update your sizes in a better way
Been trying to determine the "most" elegant solution to dropping a field from a from if the user is not is_staff/is_superuser. Found one that works, with a minimal amount of code. Originally I though to add 'close' to the 'exclude' meta or use two different forms. But this seems to document what's going on. The logic is in the 'views.py' which is where I feel it blongs.
My question: Is this safe? I've not seen forms manipulated in this fashion, it works.
models.py
class Update(models.Model):
denial = models.ForeignKey(Denial)
user = models.ForeignKey(User)
action = models.CharField(max_length=1, choices=ACTION_CHOICES)
notes = models.TextField(blank=True, null=True)
timestamp = models.DateTimeField(default=datetime.datetime.utcnow().replace(tzinfo=utc))
close = models.BooleanField(default=False)
forms.py
class UpdateForm(ModelForm):
class Meta:
model = Update
exclude = ['user', 'timestamp', 'denial', ]
views.py
class UpdateView(CreateView):
model = Update
form_class = UpdateForm
success_url = '/denials/'
template_name = 'denials/update_detail.html'
def get_form(self, form_class):
form = super(UpdateView, self).get_form(form_class)
if not self.request.user.is_staff:
form.fields.pop('close') # ordinary users cannot close tickets.
return form
Yes, your approach is perfectly valid. The FormMixin was designed so you can override methods related to managing the form in the view and it is straightforward to test.
However, should yours or someone else's dynamic modifications of the resulting form object become too extensive, it would probably be best to define several form classes and use get_form_class() to pick the correct form class to instantiate the form object from.
I'm trying to learn Django and I've ran into some confusing points. I'm currently having trouble creating a movie using a form. The idea of the form is to give the user any field he'd like to fill out. Any field that the user fills out will be updated in its respective sql table (empty fields will be ignored). But, the form keeps giving me the error "Enter a list of values" when I submit the form. To address this, I thought stuffing the data from the form into a list and then returning that list would solve this.
The first idea was to override the clean() in my ModelForm. However, because the form fails the is_valid() check in my views, the cleaned_data variable in clean() doesn't contain anything. Next, I tried to override the to_python(). However, to_python() doesn't seem to be called.
If I put __metaclass__ = models.SubfieldBase in the respective model, I receive the runtime error
"TypeError: Error when calling the
metaclass bases
metaclass conflict: the metaclass of a derived class must be a
(non-strict) subclass of the
metaclasses of all its bases"
My approach doesn't seem to work. I'm not sure how to get around the 'Enter a list of values" error! Any advice?
Here is the relevant code (updated):
models.py
""" Idea:
A movie consists of many equipments, actors, and lighting techniques. It also has a rank for the particular movie, as well as a title.
A Theater consists of many movies.
A nation consists of many theaters.
"""
from django.db import models
from django.contrib.auth.models import User
class EquipmentModel(models.Model):
equip = models.CharField(max_length=20)
# user = models.ForeignKey(User)
class ActorModel(models.Model):
actor = models.CharField(max_length=20)
# user = models.ForeignKey(User)
class LightModel(models.Model):
light = models.CharField(max_length=20)
# user = models.ForeignKey(User)
class MovieModel(models.Model):
# __metaclass__ = models.SubfieldBase
rank = models.DecimalField(max_digits=5000, decimal_places=3)
title = models.CharField(max_length=20)
equipments = models.ManyToManyField(EquipmentModel, blank=True, null=True)
actors = models.ManyToManyField(ActorModel, blank=True, null=True)
lights = models.ManyToManyField(LightModel, blank=True, null=True)
class TheaterModel(models.Model):
movies = models.ForeignKey(MovieModel)
class NationModel(models.Model):
theaters = models.ForeignKey(TheaterModel)
=====================================
forms.py
"""
These Modelforms tie in the models from models.py
Users will be able to write to any of the fields in MovieModel when creating a movie.
Users may leave any field blank (empty fields should be ignored, ie: no updates to database).
"""
from django import forms
from models import MovieModel
from django.forms.widgets import Textarea
class MovieModelForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(MovieModelForm, self).__init__(*args, **kwargs)
self.fields["actors"].widget = Textarea()
self.fields["equipments"].widget = Textarea()
self.fields["lights"].widget = Textarea()
def clean_actors(self):
data = self.cleaned_data.get('actors')
print 'cleaning actors'
return [data]
class Meta:
model = MovieModel
=============================================
views.py
""" This will display the form used to create a MovieModel """
from django.shortcuts import render_to_response
from django.template import RequestContext
from forms import MovieModelForm
def add_movie(request):
if request.method == "POST":
form = MovieModelForm(request.POST)
if form.is_valid():
new_moviemodel = form.save()
return HttpResponseRedirect('/data/')
else:
form = MovieModelForm()
return render_to_response('add_movie_form.html', {form:form,}, context_instance=RequestContext(request))
The probable problem is that the list of values provided in the text area can not be normalized into a list of Models.
See the ModelMultipleChoiceField documentation.
The field is expecting a list of valid IDs, but is probably receiving a list of text values, which django has no way of converting to the actual model instances. The to_python will be failing within the form field, not within the form itself. Therefore, the values never even reach the form.
Is there something wrong with using the built in ModelMultipleChoiceField? It will provide the easiest approach, but will require your users to scan a list of available actors (I'm using the actors field as the example here).
Before I show an example of how I'd attempt to do what you want, I must ask; how do you want to handle actors that have been entered that don't yet exist in your database? You can either create them if they exist, or you can fail. You need to make a decision on this.
# only showing the actor example, you can use something like this for other fields too
class MovieModelForm(forms.ModelForm):
actors_list = fields.CharField(required=False, widget=forms.Textarea())
class Meta:
model = MovieModel
exclude = ('actors',)
def clean_actors_list(self):
data = self.cleaned_data
actors_list = data.get('actors_list', None)
if actors_list is not None:
for actor_name in actors_list.split(','):
try:
actor = Actor.objects.get(actor=actor_name)
except Actor.DoesNotExist:
if FAIL_ON_NOT_EXIST: # decide if you want this behaviour or to create it
raise forms.ValidationError('Actor %s does not exist' % actor_name)
else: # create it if it doesnt exist
Actor(actor=actor_name).save()
return actors_list
def save(self, commit=True):
mminstance = super(MovieModelForm, self).save(commit=commit)
actors_list = self.cleaned_data.get('actors_list', None)
if actors_list is not None:
for actor_name in actors_list.split(","):
actor = Actor.objects.get(actor=actor_name)
mminstance.actors.add(actor)
mminstance.save()
return mminstance
The above is all untested code, but something approaching this should work if you really want to use a Textarea for a ModelMultipleChoiceField. If you do go down this route, and you discover errors in my code above, please either edit my answer, or provide a comment so I can. Good luck.
Edit:
The other option is to create a field that understands a comma separated list of values, but behaves in a similar way to ModelMultipleChoiceField. Looking at the source code for ModelMultipleChoiceField, it inhertis from ModelChoiceField, which DOES allow you to define which value on the model is used to normalize.
## removed code because it's no longer relevant. See Last Edit ##
Edit:
Wow, I really should have checked the django trac to see if this was already fixed. It is. See the following ticket for information. Essentially, they've done the same thing I have. They've made ModelMutipleChoiceField respect the to_field_name argument. This is only applicable for django 1.3!
The problem is, the regular ModelMultipleChoiceField will see the comma separated string, and fail because it isn't a List or Tuple. So, our job becomes a little more difficult, because we have to change the string to a list or tuple, before the regular clean method can run.
class ModelCommaSeparatedChoiceField(ModelMultipleChoiceField):
widget = Textarea
def clean(self, value):
if value is not None:
value = [item.strip() for item in value.split(",")] # remove padding
return super(ModelCommaSeparatedChoiceField, self).clean(value)
So, now your form should look like this:
class MovieModelForm(forms.ModelForm):
actors = ModelCommaSeparatedChoiceField(
required=False,
queryset=Actor.objects.filter(),
to_field_name='actor')
equipments = ModelCommaSeparatedChoiceField(
required=False,
queryset=Equipment.objects.filter(),
to_field_name='equip')
lights = ModelCommaSeparatedChoiceField(
required=False,
queryset=Light.objects.filter(),
to_field_name='light')
class Meta:
model = MovieModel
to_python AFAIK is a method for fields, not forms.
clean() occurs after individual field cleaning, so your ModelMultipleChoiceFields clean() methods are raising validation errors and thus cleaned_data does not contain anything.
You haven't provided examples for what kind of data is being input, but the answer lies in form field cleaning.
http://docs.djangoproject.com/en/dev/ref/forms/validation/#cleaning-a-specific-field-attribute
You need to write validation specific to that field that either returns the correct data in the format your field is expecting, or raises a ValidationError so your view can re-render the form with error messages.
update: You're probably missing the ModelForm __init__ -- see if that fixes it.
class MovieModelForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(MovieModelForm, self).__init__(*args, **kwargs)
self.fields["actors"].widget = Textarea()
def clean_actors(self):
data = self.cleaned_data.get('actors')
# validate incoming data. Convert the raw incoming string
# to a list of ids this field is expecting.
# if invalid, raise forms.ValidationError("Error MSG")
return data.split(',') # just an example if data was '1,3,4'
I want to make a form used to filter searches without any field being required. For example given this code:
models.py:
class Message(models.Model):
happened = models.DateTimeField()
filename = models.CharField(max_length=512, blank=True, null=True)
message = models.TextField(blank=True, null=True)
dest = models.CharField(max_length=512, blank=True, null=True)
fromhost = models.ForeignKey(Hosts, related_name='to hosts', blank=True, null=True)
TYPE_CHOICES = ( (u'Info', u'Info'), (u'Error', u'Error'), (u'File', u'File'), (u'BPS', u'BPS'),)
type = models.CharField(max_length=7, choices=TYPE_CHOICES)
job = models.ForeignKey(Jobs)
views.py:
WHEN_CHOICES = ( (u'', ''), (1, u'Today'), (2, u'Two days'), (3, u'Three Days'), (7, u'Week'),(31, u'Month'),)
class MessageSearch(ModelForm): #Class that makes a form from a model that can be customized by placing info above the class Meta
message = forms.CharField(max_length=25, required=False)
job = forms.CharField(max_length=25, required=False)
happened = forms.CharField(max_length=14, widget=forms.Select(choices=WHEN_CHOICES), required=False)
class Meta:
model = Message
That's the code I have now. As you can see it makes a form based on a model. I redefined message in the form because I'm using an icontains filter so I didn't need a giant text box. I redefined the date mostly because I didn't want to have to mess around with dates (I hate working with dates! Who doesnt?) And I changed the jobs field because otherwise I was getting a drop down list of existing jobs and I really wanted to be able to search by common words. So I was able to mark all of those as not required
The problem is it's marking all my other fields as required because in the model they're not allowed to be blank.
Now in the model they can't be blank. If they're blank then the data is bad and I don't want it in the DB. However the form is only a filter form on a page to display the data. I'm never going to save from that form so I don't care if fields are blank or not. So is there an easy way to make all fields as required=false while still using the class Meta: model = Message format in the form? It's really handy that I can make a form directly from a model.
Also this is my first serious attempt at a django app so if something is absurdly wrong please be kind :)
You can create a custom ModelForm that suit your needs. This custom ModelForm will override the save method and set all fields to be non-required:
from django.forms import ModelForm
class SearchForm(ModelForm):
def __init__(self, *args, **kwargs):
super(SearchForm, self).__init__(*args, **kwargs)
for key, field in self.fields.iteritems():
self.fields[key].required = False
So you could declare your forms by simply calling instead of the ModelForm, e.g.:
class MessageForm(SearchForm):
class Meta:
model = Message
You could also pass empty_permitted=True when you instantiate the form, e.g.,
form = MessageSearch(empty_permitted=True)
that way you can still have normal validation rules for when someone does enter data into the form.
I would give a try to the django-filter module :
http://django-filter.readthedocs.io/en/develop/
fields are not required. these are filters actually. It would look like this :
import django_filters
class MessageSearch(django_filters.FilterSet):
class Meta:
model = Message
fields = ['happened', 'filename', 'message', '...', ]
# django-filter has its own default widgets corresponding to the field
# type of the model, but you can tweak and subclass in a django way :
happened = django_filters.DateFromToRangeFilter()
mandatory, hidden filters can be defined if you want to narrow a list of model depending on something like user rights etc.
also : setup a filter on a 'reverse' relationship (the foreignkey is not in the filtered model : the model is referenced elsewhere in another table), is easy, just name the table where the foreign key of the filtered model field is :
# the 'tags' model has a fk like message = models.ForeignKey(Message...)
tags= django_filters.<some filter>(name='tags')
quick extendable and clean to setup.
please note I didn't wrote this module, I'm just very happy with it :)