Booleans as checkboxes and saving the form - django

Question

I have created a OnetoOne model for some user preference checkboxes. This is mapped to the User, and using signals I create it when the user is created. Here is what I have so far:
Model:
class DateRegexes(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
prefix_1 = models.NullBooleanField()
prefix_2 = models.NullBooleanField()
prefix_3 = models.NullBooleanField()
prefix_4 = models.NullBooleanField()
prefix_5 = models.NullBooleanField()
prefix_6 = models.NullBooleanField()
prefix_7 = models.NullBooleanField()
prefix_8 = models.NullBooleanField()
prefix_9 = models.NullBooleanField()
#receiver(post_save, sender=User)
def create_date_regexes(sender, instance, created, **kwargs):
if created:
DateRegexes.objects.create(user=instance)
#receiver(post_save, sender=User)
def save_user_date_regexes(sender, instance, **kwargs):
instance.date_prefs.save()
Form:
class DatePreferenceForm(forms.ModelForm):
class Meta:
model = DateRegexes`
View:
#login_required
def set_date_preferences(request):
if request.method == 'POST':
form = DatePreferenceForm(request.POST)
if form.is_valid():
form.save()
else:
date_prefs = get_object_or_404(DateRegexes, user=request.user)
form = DatePreferenceForm(instance = request.user.date_prefs)
return render(request, 'set_date.html', {'form': form})
Template:
{% extends 'base.html' %}
{% block title %}Date Preferences{% endblock %}
{% block content %}
{% if user.is_authenticated %}
<p>logout</p>
<form method="post">
{% csrf_token %}
{% for field in form.visible_fields %}
<div>here {{ field }}</div>
{% endfor %}
<button type="submit">Set</button>
</form>
</div>
{% else %}
<p>You are not logged in</p>
login
{% endif %}
{% endblock %}
When I execute this, the first thing that happens is that the expected checkboxes that are filled in according to their previously selected preferences, I get a bunch of dropboxes that each say:
"Unknown", "Yes", "No".
1) How can I get it show html checkboxes instead of the dropboxes?
2) When I submit the form I get:
IntegrityError at /db/set_date_preferences/
NOT NULL constraint failed: db_dateregexes.user_id
Which I understand that it is having trouble associating my form to the logged in user, but I'm not sure what the right way to associate this should be

Answer 1

You're using a NullBooleanField which can have 3 values: None, True or False. So the default widget to render such a field is a dropdown. If you want a checkbox you should decide what you want None to map to and override the fields in the DatePreferenceForm to be a BooleanField.
Second, since every user already has prefs you should initialise your form with the correct instance, even in the POST case. I don't really understand how your form can be valid since user is a required field (you should really exclude it from the form).
class DatePreferenceForm(forms.ModelForm):
class Meta:
model = DateRegexes
exclude = ['user']
# View
def set_date_preferences(request):
if request.method == 'POST':
form = DatePreferenceForm(request.POST, instance=request.user.date_prefs)
if form.is_valid():
form.save()
# would be good practice to redirect to a success page here
else:
date_prefs = get_object_or_404(DateRegexes, user=request.user)
form = DatePreferenceForm(instance = request.user.date_prefs)
return render(request, 'set_date.html', {'form': form})