I am using Django 2.2
I am creating a form dynamically, by reading a JSON definition file; the configuration file specifies the types of widgets, permitted values etc.
I have come a bit unstuck with the Select widget however, because I prepend a '--' to the list of permitted values in the list (so that I will know when a user has not selected an item).
This is the code snippet where the Select widget is created:
class myForm(forms.Form):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# ...
elif widget_type_id == WIDGET_TYPE_DROPDOWN:
CHOICES.insert(0,('-', INVALID_SELECTION))
form_field = CharField(label=the_label, widget=Select(choices=CHOICES),required=is_required)
My problem is that when the is_valid() method is invoked on my form, any rendered Select widgets are are accepted as valid regardless of the selection.
I want to implement code that has this logic (pseudocode below):
def is_valid(self):
for field_name, field in self.fields.items():
if isinstance(field.type, Select):
if field.required and field.selected_value == INVALID_SELECTION:
return False
return super().is_valid()
What would be the correct way to implement this functionality? For instance, how would I even get the selected values for the field (in the form code)?
Validate a form data: docs
by creating a custom Field with validation
a specific field by using fieldname_clean()
by overriding clean()
by using validators
? What would be the correct way to implement this functionality?
I've deviated a bit from the pseudocode in what you've asked
Validators docs
There are already many buitin validators. For this purpose, create a custom validator which checks the value in the field and raise ValidationError.
Create validator.py in your app
# validator.py
from django.core.exceptions import ValidationError
def validate_select_option(value):
if value == '-':
raise ValidationError('Invalid selection')
In forms.py import validate_select_option and add validator to the field
# forms.py
from .validator import validate_select_option
# other parts of code
form_field = CharField(label=the_label, widget=Select(choices=CHOICES), required=is_required, validator=[validate_select_option])
This validator validate_select_option can now be used not only to the field which has choices but also to any other field to validate. Anyhow, that's not its intend. So can be used to any fields with choices :)
Since you said that you are creating the form dynamically and I'm assuming that you can add additional options to Field using JSON definition file. For fieldname_clean() and clean() you will need to add these methods in your Form class. Custom field can be created and imported into. But, I think simple validators can do this easily.
? how would I even get the selected values for the field (in the form code)
If Form class method clean(self, *args, **kwargs) and fieldname_clean(self, *args, **kwargs) are used : you can access the form data by self.cleaned_data dictionary. cleaned_data is created only after is_valid().
While overriding is_valid , in-order to access the form data, we need to call the parent validation first and then work on it.
def is_valid(self, *args, **kwargs):
# cannot access self.cleaned_data since it is not created yet
valid = super(myForm, self).is_valid()
# can access self.cleaned_data since it has been created when parent is_valid() has been called
for fieldname, field in self.fields.items():
if isinstance(field, forms.CharField): # the type of widget is not considered.
if fieldname in self.cleaned_data and field.required and self.cleaned_data[fieldname] == '-':
valid = False
return valid
It's kind of hidden because you're using a CharField with a Select widget but if you look at the ChoiceField documentation it says that the empty value should be an empty string.
Assuming the form field is required=True, you should just be able to change your empty value tuple to ('', INVALID_SELECTION).
CHOICES having already values. I insert ('INVALID_SELECTION', 'INVALID_SELECTION') this. And check if the value of form_field field is INVALID_SELECTION then add error in same field. Else form is submited.
views.py
class DynamicFormView(View):
template_name = 'test.html'
def get(self, request, *args, **kwargs):
form = myForm( request.POST or None)
context = {
'form' : form,
}
return render(request, self.template_name, context)
def post(self, request,id = None, *args, **kwargs):
context = {}
form = myForm(request.POST or None,)
if form.is_valid():
if request.POST['form_field'] == 'INVALID_SELECTION':
form.add_error("form_field",_("This field is required."))
else:
form.save()
context = {
'form' : form,
}
return render(request, self.template_name, context)
forms.py
class myForm(forms.Form):
CHOICES = [
('FR', 'Freshman'),
('SO', 'Sophomore'),
('JR', 'Junior'),
('SR', 'Senior'),
('GR', 'Graduate'),
]
CHOICES.insert(0,('INVALID_SELECTION', 'INVALID_SELECTION'))
form_field = forms.ChoiceField(label='the_label',choices=CHOICES,widget=forms.Select(attrs={'class':' form-control'}),required = False)
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
def save(self):
# form is success
pass
class Meta:
model = Student
urls.py
path('dyanmic-form/create/', views.DynamicFormView.as_view(), name='dyanamic_form_create'),
Sorry my bad english language.
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.