Im trying to validate in a django form if the user entered a numeric value on a field called "usd_value" using the clean method like this :
Form.py
class CostItemsForm(ModelForm):
def __init__(self, *args, **kwargs):
super(CostItemsForm, self).__init__(*args, **kwargs)
class Meta:
model = CostItems
fields = [
'group',
'description',
'usd_value',
'rer',
'pesos_value',
'supplier',
'position',
'observations',
'validity_date',
]
def clean_usd_value(self):
if self.cleaned_data.get('usd_value'):
try:
return int(self.cleaned_data['usd_value'].strip())
except ValueError:
raise ValidationError("usd_value must be numeric")
return 0
But is not working, i mean, if i leave the field empty or enter a text value there, alert doesn't activate at all and i got error (obviously) if i try to save the form. Any help ??
Here's my views.py
class CostItemInsert(View):
template_name='cost_control_app/home.html'
def post(self, request, *args, **kwargs):
if request.user.has_perm('cost_control_app.add_costitems'):
form_insert = CostItemsForm(request.POST)
if form_insert.is_valid():
form_save = form_insert.save(commit = False)
form_save.save(force_insert = True)
messages.success(request, "cost item created")
#return HttpResponseRedirect(reverse('cost_control_app:cost_item'))
else:
messages.error(request, "couldn't save the record")
return render(request, self.template_name,{
"form_cost_item":form_insert,
})
else:
messages.error(request, "you have no perrmissions to this action")
form_cost_item = CostItemsForm()
return render(request, self.template_name,{
"form_cost_item":form_cost_item,
})
I think your function name is wrong. Your field name is usd_value but your function is clean_usd. Change it to clean_usd_value and it should work.
Check Django doc section The clean_<fieldname>().
Edit
Also your return value for your clean method is wrong. Check the django doc example, you need to return the cleaned_data not 0:
def clean_usd_value(self):
cleaned_data = self.cleaned_data.get('usd_value'):
try:
int(cleaned_data)
except ValueError:
raise ValidationError("usd_value must be numeric")
return cleaned_data
But on a second throught, you might not even need the clean_usd_value method at all, django form field should have the default validation for you. Remove entirely the clean_usd_value method and see if it works.
I don't think you need custom validation for this. In fact, I think the builtin validation for django.forms.FloatField is going to be better than what you have.
Based on your error, I'm assuming that the form isn't using a FloatField for usd_value, and that's a bit odd. Make sure that your CostItems model has usd_value defined as a django.db.models.FloatField like below.
from django.db import models
class CostItems(models.Model):
usd_value = models.FloatField()
# other stuff
Once you do this, your CostItemsForm should automatically use django.forms.FloatField for usd_value. If it doesn't, you can always define this field explicitly.
from django import forms
class CostItemsForm(ModelForm):
usd_value = forms.FloatField(required=True)
class Meta:
model = CostItems
fields = [
'group',
'description',
'usd_value',
'rer',
'pesos_value',
'supplier',
'position',
'observations',
'validity_date',
]
If neither of these suggestions is helpful, please post your CostItems model.
In my django formset, I am trying to display a foreign key field with an input instead of a select:
class MinAttend(models.Model):
act = models.ForeignKey(Act)
country = models.ForeignKey(Country)
verbatim = models.ForeignKey(Verbatim)
def __unicode__(self):
return u"%s" % self.verbatim
class MinAttendForm(forms.ModelForm):
country=forms.ModelChoiceField(queryset=Country.objects.all(), empty_label="Select a country")
status=forms.ModelChoiceField(queryset=Status.objects.values_list('status', flat = True).distinct(), empty_label="Select a status")
verbatim=forms.CharField(max_length=300)
class Meta:
model=MinAttend
#fields used for the validation and order
fields = ('country', 'status', 'verbatim')
For the verbatim field, I do have an input box instead of a select but when I want to update a formset, I have the verbatim id instead of its corresponding text:
Here is how I initialize the form:
class MinAttendUpdate(UpdateView):
object=None
model = MinAttend
form_class=MinAttendForm
nb_extra_forms=3
def post(self, request, *args, **kwargs):
attendances=MinAttend.objects.filter(...)
#set the number of forms to the number of ministers + 3 extra form to fill if needed
MinAttendFormSet = modelformset_factory(self.model, form=self.form_class, extra=len(attendances), max_num=len(attendances)+self.nb_extra_forms, can_delete=True)
formset=MinAttendFormSet(queryset=attendances)
I have tried two things:
Instead of the last line I have the following code:
initials=[]
#display text of verbatim instead of id
for index in range(len(attendances)):
initials.append({"verbatim": attendances[index].verbatim.verbatim})
print "initials", initials
formset=MinAttendFormSet(queryset=attendances, initial=initials)
I have overridden the init method of the form:
#~ #verbatim text instead of id for the verbatim field
def __init__(self, *args, **kwargs):
super(MinAttendForm, self).__init__(*args, **kwargs)
instance = kwargs.get("instance", None)
if instance!=None:
print "instance", instance.verbatim.verbatim
self.fields["verbatim"].initial = instance.verbatim.verbatim
None of these methods works, I still get numbers instead of text! What is curious is that I do see text for the verbatim field but only for the three extra forms. Normal?
EDIT - from Bernd Jerzyna comment
In my form:
from django.forms.models import BaseModelFormSet
class MinAttendFormSet(BaseModelFormSet):
def __init__(self, *args, **kwargs):
super(MinAttendFormSet, self).__init__(*args, **kwargs)
for form in self.forms:
#skip extra forms
if not form.empty_permitted:
form.fields['verbatim'].initial= form.instance.verbatim
print "verbatim MinAttendFormSet", form.instance.verbatim
In my view:
from forms import MinAttendForm, MinAttendFormSet
my_formset = modelformset_factory(self.model, form=self.form_class, formset=MinAttendFormSet)
formset = my_formset(request.POST, queryset=attendances)
When I do a print of the text of each verbatim, I see the correct text displayed. However, I still see numbers (primary key ids) in the form of my web page ;(.
What's wrong?
I think something like this should work:
Implement the init method of your formset like
def __init__(self, *args, **kwargs):
...
super(MinAttendFormSet, self).__init__(*args, **kwargs)
for form in self.forms:
form.fields['verbatim'].initial= form.instance.verbatim
That would also require your Verbatim model to have something like:
def __unicode__(self):
return u'%s' % (self.name)
This is my understanding of it...
As a select widget, the verbatim is displayed with the __unicode__ results, but the value 'behind the scenes' is the PK/verbatim-id, ie the HTML <option> tag has a value and 'label'. When you change it to a text input widget, it is expecting you to enter the PK, hence why you are seeing the numbers.
For the solution, I am not sure. You could write some code to accept the verbatim-text, rather than the pk/verbatim-id. The problem with this though, is that if the text is not written exactly, django won't find a match. Also, if more than 1 verbatim has the same text, django wouldn't know which one to use (unless you have set unique=true on the model field for text). You could also set the verbatim-text as the PK.
Perhaps using something like Django-Select2 will give you the desired UI?
I've just discovered that Django doesn't automatically strip out extra whitespace from form field inputs, and I think I understand the rationale ('frameworks shouldn't be altering user input').
I think I know how to remove the excess whitespace using python's re:
#data = re.sub('\A\s+|\s+\Z', '', data)
data = data.strip()
data = re.sub('\s+', ' ', data)
The question is where should I do this? Presumably this should happen in one of the form's clean stages, but which one? Ideally, I would like to clean all my fields of extra whitespace. If it should be done in the clean_field() method, that would mean I would have to have a lot of clean_field() methods that basically do the same thing, which seems like a lot of repetition.
If not the form's cleaning stages, then perhaps in the model that the form is based on?
My approach is borrowed from here. But instead of subclassing django.forms.Form, I use a mixin. That way I can use it with both Form and ModelForm. The method defined here overrides BaseForm's _clean_fields method.
class StripWhitespaceMixin(object):
def _clean_fields(self):
for name, field in self.fields.items():
# value_from_datadict() gets the data from the data dictionaries.
# Each widget type knows how to retrieve its own data, because some
# widgets split data over several HTML fields.
value = field.widget.value_from_datadict(self.data, self.files, self.add_prefix(name))
try:
if isinstance(field, FileField):
initial = self.initial.get(name, field.initial)
value = field.clean(value, initial)
else:
if isinstance(value, basestring):
value = field.clean(value.strip())
else:
value = field.clean(value)
self.cleaned_data[name] = value
if hasattr(self, 'clean_%s' % name):
value = getattr(self, 'clean_%s' % name)()
self.cleaned_data[name] = value
except ValidationError as e:
self._errors[name] = self.error_class(e.messages)
if name in self.cleaned_data:
del self.cleaned_data[name]
To use, simply add the mixin to your form
class MyForm(StripeWhitespaceMixin, ModelForm):
...
Also, if you want to trim whitespace when saving models that do not have a form you can use the following mixin. Models without forms aren't validated by default. I use this when I create objects based off of json data returned from external rest api call.
class ValidateModelMixin(object):
def clean(self):
for field in self._meta.fields:
value = getattr(self, field.name)
if value:
# ducktyping attempt to strip whitespace
try:
setattr(self, field.name, value.strip())
except Exception:
pass
def save(self, *args, **kwargs):
self.full_clean()
super(ValidateModelMixin, self).save(*args, **kwargs)
Then in your models.py
class MyModel(ValidateModelMixin, Model):
....
Create a custom model field so that your custom form field will be used automatically.
class TrimmedCharFormField(forms.CharField):
def clean(self, value):
if value:
value = value.strip()
return super(TrimmedCharFormField, self).clean(value)
# (If you use South) add_introspection_rules([], ["^common\.fields\.TrimmedCharField"])
class TrimmedCharField(models.CharField):
__metaclass__ = models.SubfieldBase
def formfield(self, **kwargs):
return super(TrimmedCharField, self).formfield(form_class=TrimmedCharFormField, **kwargs)
Then in your models just replace django.db.models.CharField with TrimmedCharField
How about adding that to the def clean(self): in the form?
For further documentation see:
https://docs.djangoproject.com/en/dev/ref/forms/validation/#cleaning-and-validating-fields-that-depend-on-each-other
Your method could look something like this:
def clean(self):
cleaned_data = self.cleaned_data
for k in self.cleaned_data:
data = re.sub('\A\s+', '', self.cleaned_data[k])
data = re.sub('\s+\Z', '', data)
data = re.sub('\s+', ' ', data)
cleaned_data[k]=data
return cleaned_data
Use the following mixin:
class StripWhitespaceMixin(object):
def full_clean(self):
# self.data can be dict (usually empty) or QueryDict here.
self.data = self.data.copy()
is_querydict = hasattr(self.data, 'setlist')
strip = lambda val: val.strip()
for k in list(self.data.keys()):
if is_querydict:
self.data.setlist(k, map(strip, self.data.getlist(k)))
else:
self.data[k] = strip(self.data[k])
super(StripWhitespaceMixin, self).full_clean()
Add this as a mixin to your form e.g.:
class MyForm(StripWhitespaceMixin, Form):
pass
This is similar to pymarco's answer, but doesn't involve copy-pasting and then modifying Django code (the contents of the _clean_fields method).
Instead, it overrides full_clean but calls the original full_clean method after making some adjustments to the input data. This makes it less dependent on implementation details of Django's Form class that might change (and in fact have changed since that answer).
Since Django 1.9 you can use the strip keyword argument in the field of your form definition :
strip¶
New in Django 1.9.
If True (default), the value will be stripped of leading and trailing whitespace.
Which should give something like :
class MyForm(forms.Form):
myfield = forms.CharField(min_length=42, strip=True)
And since its default value is True this should be automatic with django>=1.9.
It's also relevant with RegexField.
In this case, it could be useful to create your own form field (it's not that hard as it sounds). In the clean() method you would remove that extra whitespaces.
Quoting the documentation:
You can easily create custom Field classes. To do this, just create a
subclass of django.forms.Field. Its only requirements are that it
implement a clean() method and that its __init__() method accept the
core arguments (required, label, initial, widget,
help_text).
More about it: https://docs.djangoproject.com/en/1.3/ref/forms/fields/#creating-custom-fields
One way to do this is to specify custom form widget that strips whitespace:
>>> from django import forms
>>> class StripTextField(forms.CharField):
... def clean(self,value):
... return value.strip()
...
>>> f = StripTextField()
>>> f.clean(' hello ')
'hello'
Then to use this in your ModelForm:
class MyForm(ModelForm):
strip_field = StripTextField()
class Meta:
model = MyModel
However, the best place to do this is in your view after the form has been validated; before you do any inserts into the db or other manipulation of data if you are using ModelForms.
You can always create your own non-ModelForm forms and control every aspect of the field and validation that way.
ModelForm's validation adds checks for values that would violate the db constraints; so if the field can accept ' hello ' as a valid input, ModelForm's is_valid() would have no reason to strip the whitespaces (as it wouldn't make for arbitrary clean logic, in addition to what you mentioned "frameworks shouldn't alter user's input").
If you want to strip() every CharField in your project; it may be simplest to monkeypatch CharField's default cleaning method.
within: monkey_patch/__init__.py
from django.forms.fields import CharField
def new_clean(self, value):
""" Strip leading and trailing whitespace on all CharField's """
if value:
# We try/catch here, because other fields subclass CharField. So I'm not totally certain that value will always be stripable.
try:
value = value.strip()
except:
pass
return super(CharField, self).clean(value)
CharField.clean = new_clean
In a Django form, how do I make a field read-only (or disabled)?
When the form is being used to create a new entry, all fields should be enabled - but when the record is in update mode some fields need to be read-only.
For example, when creating a new Item model, all fields must be editable, but while updating the record, is there a way to disable the sku field so that it is visible, but cannot be edited?
class Item(models.Model):
sku = models.CharField(max_length=50)
description = models.CharField(max_length=200)
added_by = models.ForeignKey(User)
class ItemForm(ModelForm):
class Meta:
model = Item
exclude = ('added_by')
def new_item_view(request):
if request.method == 'POST':
form = ItemForm(request.POST)
# Validate and save
else:
form = ItemForm()
# Render the view
Can class ItemForm be reused? What changes would be required in the ItemForm or Item model class? Would I need to write another class, "ItemUpdateForm", for updating the item?
def update_item_view(request):
if request.method == 'POST':
form = ItemUpdateForm(request.POST)
# Validate and save
else:
form = ItemUpdateForm()
As pointed out in this answer, Django 1.9 added the Field.disabled attribute:
The disabled boolean argument, when set to True, disables a form field using the disabled HTML attribute so that it won’t be editable by users. Even if a user tampers with the field’s value submitted to the server, it will be ignored in favor of the value from the form’s initial data.
With Django 1.8 and earlier, to disable entry on the widget and prevent malicious POST hacks you must scrub the input in addition to setting the readonly attribute on the form field:
class ItemForm(ModelForm):
def __init__(self, *args, **kwargs):
super(ItemForm, self).__init__(*args, **kwargs)
instance = getattr(self, 'instance', None)
if instance and instance.pk:
self.fields['sku'].widget.attrs['readonly'] = True
def clean_sku(self):
instance = getattr(self, 'instance', None)
if instance and instance.pk:
return instance.sku
else:
return self.cleaned_data['sku']
Or, replace if instance and instance.pk with another condition indicating you're editing. You could also set the attribute disabled on the input field, instead of readonly.
The clean_sku function will ensure that the readonly value won't be overridden by a POST.
Otherwise, there is no built-in Django form field which will render a value while rejecting bound input data. If this is what you desire, you should instead create a separate ModelForm that excludes the uneditable field(s), and just print them inside your template.
Django 1.9 added the Field.disabled attribute: https://docs.djangoproject.com/en/stable/ref/forms/fields/#disabled
The disabled boolean argument, when set to True, disables a form field using the disabled HTML attribute so that it won’t be editable by users. Even if a user tampers with the field’s value submitted to the server, it will be ignored in favor of the value from the form’s initial data.
Setting readonly on a widget only makes the input in the browser read-only. Adding a clean_sku which returns instance.sku ensures the field value will not change on form level.
def clean_sku(self):
if self.instance:
return self.instance.sku
else:
return self.fields['sku']
This way you can use model's (unmodified save) and avoid getting the field required error.
awalker's answer helped me a lot!
I've changed his example to work with Django 1.3, using get_readonly_fields.
Usually you should declare something like this in app/admin.py:
class ItemAdmin(admin.ModelAdmin):
...
readonly_fields = ('url',)
I've adapted in this way:
# In the admin.py file
class ItemAdmin(admin.ModelAdmin):
...
def get_readonly_fields(self, request, obj=None):
if obj:
return ['url']
else:
return []
And it works fine. Now if you add an Item, the url field is read-write, but on change it becomes read-only.
To make this work for a ForeignKey field, a few changes need to be made. Firstly, the SELECT HTML tag does not have the readonly attribute. We need to use disabled="disabled" instead. However, then the browser doesn't send any form data back for that field. So we need to set that field to not be required so that the field validates correctly. We then need to reset the value back to what it used to be so it's not set to blank.
So for foreign keys you will need to do something like:
class ItemForm(ModelForm):
def __init__(self, *args, **kwargs):
super(ItemForm, self).__init__(*args, **kwargs)
instance = getattr(self, 'instance', None)
if instance and instance.id:
self.fields['sku'].required = False
self.fields['sku'].widget.attrs['disabled'] = 'disabled'
def clean_sku(self):
# As shown in the above answer.
instance = getattr(self, 'instance', None)
if instance:
return instance.sku
else:
return self.cleaned_data.get('sku', None)
This way the browser won't let the user change the field, and will always POST as it it was left blank. We then override the clean method to set the field's value to be what was originally in the instance.
For Django 1.2+, you can override the field like so:
sku = forms.CharField(widget = forms.TextInput(attrs={'readonly':'readonly'}))
I made a MixIn class which you may inherit to be able to add a read_only iterable field which will disable and secure fields on the non-first edit:
(Based on Daniel's and Muhuk's answers)
from django import forms
from django.db.models.manager import Manager
# I used this instead of lambda expression after scope problems
def _get_cleaner(form, field):
def clean_field():
value = getattr(form.instance, field, None)
if issubclass(type(value), Manager):
value = value.all()
return value
return clean_field
class ROFormMixin(forms.BaseForm):
def __init__(self, *args, **kwargs):
super(ROFormMixin, self).__init__(*args, **kwargs)
if hasattr(self, "read_only"):
if self.instance and self.instance.pk:
for field in self.read_only:
self.fields[field].widget.attrs['readonly'] = "readonly"
setattr(self, "clean_" + field, _get_cleaner(self, field))
# Basic usage
class TestForm(AModelForm, ROFormMixin):
read_only = ('sku', 'an_other_field')
I ran across a similar problem.
It looks like I was able to solve it by defining a get_readonly_fields method in my ModelAdmin class.
Something like this:
# In the admin.py file
class ItemAdmin(admin.ModelAdmin):
def get_readonly_display(self, request, obj=None):
if obj:
return ['sku']
else:
return []
The nice thing is that obj will be None when you are adding a new Item, or it will be the object being edited when you are changing an existing Item.
get_readonly_display is documented here.
I've just created the simplest possible widget for a readonly field - I don't really see why forms don't have this already:
class ReadOnlyWidget(widgets.Widget):
"""Some of these values are read only - just a bit of text..."""
def render(self, _, value, attrs=None):
return value
In the form:
my_read_only = CharField(widget=ReadOnlyWidget())
Very simple - and gets me just output. Handy in a formset with a bunch of read only values.
Of course - you could also be a bit more clever and give it a div with the attrs so you can append classes to it.
For django 1.9+
You can use Fields disabled argument to make field disable.
e.g. In following code snippet from forms.py file , I have made employee_code field disabled
class EmployeeForm(forms.ModelForm):
employee_code = forms.CharField(disabled=True)
class Meta:
model = Employee
fields = ('employee_code', 'designation', 'salary')
Reference
https://docs.djangoproject.com/en/dev/ref/forms/fields/#disabled
How I do it with Django 1.11 :
class ItemForm(ModelForm):
disabled_fields = ('added_by',)
class Meta:
model = Item
fields = '__all__'
def __init__(self, *args, **kwargs):
super(ItemForm, self).__init__(*args, **kwargs)
for field in self.disabled_fields:
self.fields[field].disabled = True
One simple option is to just type form.instance.fieldName in the template instead of form.fieldName.
You can elegantly add readonly in the widget:
class SurveyModaForm(forms.ModelForm):
class Meta:
model = Survey
fields = ['question_no']
widgets = {
'question_no':forms.NumberInput(attrs={'class':'form-control','readonly':True}),
}
Yet again, I am going to offer one more solution :) I was using Humphrey's code, so this is based off of that.
However, I ran into issues with the field being a ModelChoiceField. Everything would work on the first request. However, if the formset tried to add a new item and failed validation, something was going wrong with the "existing" forms where the SELECTED option was being reset to the default ---------.
Anyway, I couldn't figure out how to fix that. So instead, (and I think this is actually cleaner in the form), I made the fields HiddenInputField(). This just means you have to do a little more work in the template.
So the fix for me was to simplify the Form:
class ItemForm(ModelForm):
def __init__(self, *args, **kwargs):
super(ItemForm, self).__init__(*args, **kwargs)
instance = getattr(self, 'instance', None)
if instance and instance.id:
self.fields['sku'].widget=HiddenInput()
And then in the template, you'll need to do some manual looping of the formset.
So, in this case you would do something like this in the template:
<div>
{{ form.instance.sku }} <!-- This prints the value -->
{{ form }} <!-- Prints form normally, and makes the hidden input -->
</div>
This worked a little better for me and with less form manipulation.
I was going into the same problem so I created a Mixin that seems to work for my use cases.
class ReadOnlyFieldsMixin(object):
readonly_fields =()
def __init__(self, *args, **kwargs):
super(ReadOnlyFieldsMixin, self).__init__(*args, **kwargs)
for field in (field for name, field in self.fields.iteritems() if name in self.readonly_fields):
field.widget.attrs['disabled'] = 'true'
field.required = False
def clean(self):
cleaned_data = super(ReadOnlyFieldsMixin,self).clean()
for field in self.readonly_fields:
cleaned_data[field] = getattr(self.instance, field)
return cleaned_data
Usage, just define which ones must be read only:
class MyFormWithReadOnlyFields(ReadOnlyFieldsMixin, MyForm):
readonly_fields = ('field1', 'field2', 'fieldx')
As a useful addition to Humphrey's post, I had some issues with django-reversion, because it still registered disabled fields as 'changed'. The following code fixes the problem.
class ItemForm(ModelForm):
def __init__(self, *args, **kwargs):
super(ItemForm, self).__init__(*args, **kwargs)
instance = getattr(self, 'instance', None)
if instance and instance.id:
self.fields['sku'].required = False
self.fields['sku'].widget.attrs['disabled'] = 'disabled'
def clean_sku(self):
# As shown in the above answer.
instance = getattr(self, 'instance', None)
if instance:
try:
self.changed_data.remove('sku')
except ValueError, e:
pass
return instance.sku
else:
return self.cleaned_data.get('sku', None)
As I can't yet comment (muhuk's solution), I'll response as a separate answer. This is a complete code example, that worked for me:
def clean_sku(self):
if self.instance and self.instance.pk:
return self.instance.sku
else:
return self.cleaned_data['sku']
Based on Yamikep's answer, I found a better and very simple solution which also handles ModelMultipleChoiceField fields.
Removing field from form.cleaned_data prevents fields from being saved:
class ReadOnlyFieldsMixin(object):
readonly_fields = ()
def __init__(self, *args, **kwargs):
super(ReadOnlyFieldsMixin, self).__init__(*args, **kwargs)
for field in (field for name, field in self.fields.iteritems() if
name in self.readonly_fields):
field.widget.attrs['disabled'] = 'true'
field.required = False
def clean(self):
for f in self.readonly_fields:
self.cleaned_data.pop(f, None)
return super(ReadOnlyFieldsMixin, self).clean()
Usage:
class MyFormWithReadOnlyFields(ReadOnlyFieldsMixin, MyForm):
readonly_fields = ('field1', 'field2', 'fieldx')
if your need multiple read-only fields.you can use any of methods given below
method 1
class ItemForm(ModelForm):
readonly = ('sku',)
def __init__(self, *arg, **kwrg):
super(ItemForm, self).__init__(*arg, **kwrg)
for x in self.readonly:
self.fields[x].widget.attrs['disabled'] = 'disabled'
def clean(self):
data = super(ItemForm, self).clean()
for x in self.readonly:
data[x] = getattr(self.instance, x)
return data
method 2
inheritance method
class AdvancedModelForm(ModelForm):
def __init__(self, *arg, **kwrg):
super(AdvancedModelForm, self).__init__(*arg, **kwrg)
if hasattr(self, 'readonly'):
for x in self.readonly:
self.fields[x].widget.attrs['disabled'] = 'disabled'
def clean(self):
data = super(AdvancedModelForm, self).clean()
if hasattr(self, 'readonly'):
for x in self.readonly:
data[x] = getattr(self.instance, x)
return data
class ItemForm(AdvancedModelForm):
readonly = ('sku',)
Two more (similar) approaches with one generalized example:
1) first approach - removing field in save() method, e.g. (not tested ;) ):
def save(self, *args, **kwargs):
for fname in self.readonly_fields:
if fname in self.cleaned_data:
del self.cleaned_data[fname]
return super(<form-name>, self).save(*args,**kwargs)
2) second approach - reset field to initial value in clean method:
def clean_<fieldname>(self):
return self.initial[<fieldname>] # or getattr(self.instance, fieldname)
Based on second approach I generalized it like this:
from functools import partial
class <Form-name>(...):
def __init__(self, ...):
...
super(<Form-name>, self).__init__(*args, **kwargs)
...
for i, (fname, field) in enumerate(self.fields.iteritems()):
if fname in self.readonly_fields:
field.widget.attrs['readonly'] = "readonly"
field.required = False
# set clean method to reset value back
clean_method_name = "clean_%s" % fname
assert clean_method_name not in dir(self)
setattr(self, clean_method_name, partial(self._clean_for_readonly_field, fname=fname))
def _clean_for_readonly_field(self, fname):
""" will reset value to initial - nothing will be changed
needs to be added dynamically - partial, see init_fields
"""
return self.initial[fname] # or getattr(self.instance, fieldname)
For the Admin version, I think this is a more compact way if you have more than one field:
def get_readonly_fields(self, request, obj=None):
skips = ('sku', 'other_field')
fields = super(ItemAdmin, self).get_readonly_fields(request, obj)
if not obj:
return [field for field in fields if not field in skips]
return fields
Here is a slightly more involved version, based on christophe31's answer. It does not rely on the "readonly" attribute. This makes its problems, like select boxes still being changeable and datapickers still popping up, go away.
Instead, it wraps the form fields widget in a readonly widget, thus making the form still validate. The content of the original widget is displayed inside <span class="hidden"></span> tags. If the widget has a render_readonly() method it uses that as the visible text, otherwise it parses the HTML of the original widget and tries to guess the best representation.
import django.forms.widgets as f
import xml.etree.ElementTree as etree
from django.utils.safestring import mark_safe
def make_readonly(form):
"""
Makes all fields on the form readonly and prevents it from POST hacks.
"""
def _get_cleaner(_form, field):
def clean_field():
return getattr(_form.instance, field, None)
return clean_field
for field_name in form.fields.keys():
form.fields[field_name].widget = ReadOnlyWidget(
initial_widget=form.fields[field_name].widget)
setattr(form, "clean_" + field_name,
_get_cleaner(form, field_name))
form.is_readonly = True
class ReadOnlyWidget(f.Select):
"""
Renders the content of the initial widget in a hidden <span>. If the
initial widget has a ``render_readonly()`` method it uses that as display
text, otherwise it tries to guess by parsing the html of the initial widget.
"""
def __init__(self, initial_widget, *args, **kwargs):
self.initial_widget = initial_widget
super(ReadOnlyWidget, self).__init__(*args, **kwargs)
def render(self, *args, **kwargs):
def guess_readonly_text(original_content):
root = etree.fromstring("<span>%s</span>" % original_content)
for element in root:
if element.tag == 'input':
return element.get('value')
if element.tag == 'select':
for option in element:
if option.get('selected'):
return option.text
if element.tag == 'textarea':
return element.text
return "N/A"
original_content = self.initial_widget.render(*args, **kwargs)
try:
readonly_text = self.initial_widget.render_readonly(*args, **kwargs)
except AttributeError:
readonly_text = guess_readonly_text(original_content)
return mark_safe("""<span class="hidden">%s</span>%s""" % (
original_content, readonly_text))
# Usage example 1.
self.fields['my_field'].widget = ReadOnlyWidget(self.fields['my_field'].widget)
# Usage example 2.
form = MyForm()
make_readonly(form)
Today I encountered the exact same problem for a similar use case. However, I had to deal with a class-based views. Class-based views allow inheriting attributes and methods thus making it easier to reuse code in a neat manner.
I will answer your question by discussing the code needed for creating a profile page for users. On this page, they can update their personal information. However, I wanted to show an email field without allowing the user to change the information.
Yes, I could have just left out the email field but my OCD would not allow it.
In the example below I used a form class in combination with the disabled = True method. This code is tested on Django==2.2.7.
# form class in forms.py
# Alter import User if you have created your own User class with Django default as abstract class.
from .models import User
# from django.contrib.auth.models import User
# Same goes for these forms.
from django.contrib.auth.forms import UserCreationForm, UserChangeForm
class ProfileChangeForm(UserChangeForm):
class Meta(UserCreationForm)
model = User
fields = ['first_name', 'last_name', 'email',]
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['email'].disabled = True
As one can see, the needed user fields are specified. These are the fields that must be shown on the profile page. If other fields need to be added one has to specify them in the User class and add the attribute name to the fields list of the Meta class of this form.
After getting the required metadata the __init__ method is called initializing the form. However, within this method, the email field parameter 'disabled' is set to True. By doing so the behavior of the field in the front-end is altered resulting in a read-only field that one cannot edit even if one changes the HTML code. Reference Field.disabled
For completion, in the example below one can see the class-based views needed to use the form.
# view class in views.py
from django.contrib import messages
from django.contrib.messages.views import SuccessMessageMixin
from django.contrib.auth.mixins import LoginRequiredMixin
from django.views.generic import TemplateView, UpdateView
from django.utils.translation import gettext_lazy as _
class ProfileView(LoginRequiredMixin, TemplateView):
template_name = 'app_name/profile.html'
model = User
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context.update({'user': self.request.user, })
return context
class UserUpdateView(LoginRequiredMixin, SuccesMessageMixin, UpdateView):
template_name = 'app_name/update_profile.html'
model = User
form_class = ProfileChangeForm
success_message = _("Successfully updated your personal information")
def get_success_url(self):
# Please note, one has to specify a get_absolute_url() in the User class
# In my case I return: reverse("app_name:profile")
return self.request.user.get_absolute_url()
def get_object(self, **kwargs):
return self.request.user
def form_valid(self, form):
messages.add_message(self.request, messages.INFO, _("Successfully updated your profile"))
return super().form_valid(form)
The ProfileView class only shows an HTML page with some information about the user. Furthermore, it holds a button that if pressed leads to an HTML page configured by the UserUpdateView, namely 'app_name/update_profile.html'. As one can see, the UserUpdateView holds two extra attributes, namely 'form_class' and 'success_message'.
The view knows that every field on the page must be filled with data from the User model. However, by introducing the 'form_class' attribute the view does not get the default layout of the User fields. Instead, it is redirected to retrieve the fields through the form class. This has a huge advantage in the sense of flexibility.
By using form classes it is possible to show different fields with different restrictions for different users. If one sets the restrictions within the model itself every user would get the same treatment.
The template itself is not that spectacular but can be seen below.
# HTML template in 'templates/app_name/update_profile.html'
{% extends "base.html" %}
{% load static %}
{% load crispy_form_tags %}
{% block content %}
<h1>
Update your personal information
<h1/>
<div>
<form class="form-horizontal" method="post" action="{% url 'app_name:update' %}">
{% csrf_token %}
{{ form|crispy }}
<div class="btn-group">
<button type="submit" class="btn btn-primary">
Update
</button>
</div>
</div>
{% endblock %}
As can be seen, the form tag holds an action tag that holds the view URL routing.
After pressing the Update button the UserUpdateView gets activated and it validates if all conditions are met. If so, the form_valid method is triggered and adds a success message. After successfully updating the data the user is returned to the specified URL in the get_success_url method.
Below one can find the code allowing the URL routing for the views.
# URL routing for views in urls.py
from django.urls import path
from . import views
app_name = 'app_name'
urlpatterns = [
path('profile/', view=views.ProfileView.as_view(), name='profile'),
path('update/', view=views.UserUpdateView.as_view(), name='update'),
]
There you have it. A fully worked out implementation of class-based views using form so one can alter an email field to be read-only and disabled.
My apologies for the extremely detailed example. There might be more efficient ways to design the class-based views, but this should work. Of course, I might have been wrong about some things said. I'm still learning as well. If anyone has any comments or improvements let me know!
You can do it just like this:
Check if the request is update or save a new object.
If request is update then disable field sku.
If request is to add a new object then you must render the form with out disabling the field sku.
Here is an example of how to do like this.
class Item(models.Model):
sku = models.CharField(max_length=50)
description = models.CharField(max_length=200)
added_by = models.ForeignKey(User)
class ItemForm(ModelForm):
def disable_sku_field(self):
elf.fields['sku'].widget.attrs['readonly'] = True
class Meta:
model = Item
exclude = ('added_by')
def new_item_view(request):
if request.method == 'POST':
form = ItemForm(request.POST)
# Just create an object or instance of the form.
# Validate and save
else:
form = ItemForm()
# Render the view
def update_item_view(request):
if request.method == 'POST':
form = ItemForm(request.POST)
# Just create an object or instance of the form.
# Validate and save
else:
form = ItemForm()
form.disable_sku_field() # call the method that will disable field.
# Render the view with the form that will have the `sku` field disabled on it.
Is this the simplest way?
Right in a view code something like this:
def resume_edit(request, r_id):
.....
r = Resume.get.object(pk=r_id)
resume = ResumeModelForm(instance=r)
.....
resume.fields['email'].widget.attrs['readonly'] = True
.....
return render(request, 'resumes/resume.html', context)
It works fine!
If you are working with Django ver < 1.9 (the 1.9 has added Field.disabled attribute) you could try to add following decorator to your form __init__ method:
def bound_data_readonly(_, initial):
return initial
def to_python_readonly(field):
native_to_python = field.to_python
def to_python_filed(_):
return native_to_python(field.initial)
return to_python_filed
def disable_read_only_fields(init_method):
def init_wrapper(*args, **kwargs):
self = args[0]
init_method(*args, **kwargs)
for field in self.fields.values():
if field.widget.attrs.get('readonly', None):
field.widget.attrs['disabled'] = True
setattr(field, 'bound_data', bound_data_readonly)
setattr(field, 'to_python', to_python_readonly(field))
return init_wrapper
class YourForm(forms.ModelForm):
#disable_read_only_fields
def __init__(self, *args, **kwargs):
...
The main idea is that if field is readonly you don't need any other value except initial.
P.S: Don't forget to set yuor_form_field.widget.attrs['readonly'] = True
Start from disable fields mixin:
class ModelAllDisabledFormMixin(forms.ModelForm):
def __init__(self, *args, **kwargs):
'''
This mixin to ModelForm disables all fields. Useful to have detail view based on model
'''
super().__init__(*args, **kwargs)
form_fields = self.fields
for key in form_fields.keys():
form_fields[key].disabled = True
then:
class MyModelAllDisabledForm(ModelAllDisabledFormMixin, forms.ModelForm):
class Meta:
model = MyModel
fields = '__all__'
prepare view:
class MyModelDetailView(LoginRequiredMixin, UpdateView):
model = MyModel
template_name = 'my_model_detail.html'
form_class = MyModelAllDisabledForm
place this in my_model_detail.html template:
<div class="form">
<form method="POST" enctype="multipart/form-data">
{% csrf_token %}
{{ form | crispy }}
</form>
</div>
You will obtain same form as in update view but with all fields disabled.
Based on the answer from #paeduardo (which is overkill), you can disable a field in the form class initializer:
class RecordForm(ModelForm):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
var = self.fields['the_field']
var.disabled = True
If you are using Django admin, here is the simplest solution.
class ReadonlyFieldsMixin(object):
def get_readonly_fields(self, request, obj=None):
if obj:
return super(ReadonlyFieldsMixin, self).get_readonly_fields(request, obj)
else:
return tuple()
class MyAdmin(ReadonlyFieldsMixin, ModelAdmin):
readonly_fields = ('sku',)
I think your best option would just be to include the readonly attribute in your template rendered in a <span> or <p> rather than include it in the form if it's readonly.
Forms are for collecting data, not displaying it. That being said, the options to display in a readonly widget and scrub POST data are fine solutions.