Question

I have a simple form in Django that looks like this:

class SettingForm(forms.Form):
    theme = forms.CharField(rrequired=True,
        initial='multgi'
    )
    defaultinputmessage = forms.CharField(required=True,
        initial='Type here to begin..'
    )

…and the model to store it looks like:

class Setting(models.Model):
    name = models.CharField(
        null=False, max_length=255
    )
    value= models.CharField(
        null=False, max_length=255
    )

When the form is submitted, how can i store the form fields as key value pairs and then when the page is rendered, how can I initialize the form with the key’s value. I’ve tried looking for an implementation of this but have been unable to find one.

Any help?

Thanks.

Answer 1

Here’s how I did it.

I needed to do this because I had a Model that stored information as key value pairs and I needed to build a ModelForm on that Model but the ModelForm should display the key-value pairs as fields i.e. pivot the rows to columns. By default, the get() method of the Model always returns a Model instance of itself and I needed to use a custom Model. Here’s what my key-value pair model looked like:

class Setting(models.Model):
    domain = models.ForeignKey(Domain)
    name = models.CharField(null=False, max_length=255)
    value = models.CharField(null=False, max_length=255)

    objects = SettingManager()

I built a custom manager on this to override the get() method:

class SettingManager(models.Manager):

    def get(self, *args, **kwargs):
        from modules.customer.proxies import *
        from modules.customer.models import *

        object = type('DomainSettings', (SettingProxy,), {'__module__' : 'modules.customer'})()
        for pair in self.filter(*args, **kwargs): setattr(object, pair.name, pair.value)

        setattr(object, 'domain', Domain.objects.get(id=int(kwargs['domain__exact'])))
        return object

This Manager would instantiate an instance of this abstract model. (Abstract models don’t have tables so Django doesn’t throw up errors)

class SettingProxy(models.Model):

    domain = models.ForeignKey(Domain, null=False, verbose_name="Domain")
    theme = models.CharField(null=False, default='mytheme', max_length=16)
    message = models.CharField(null=False, default='Waddup', max_length=64)

    class Meta:
        abstract = True

    def __init__(self, *args, **kwargs):
        super(SettingProxy, self).__init__(*args, **kwargs)
        for field in self._meta.fields:
            if isinstance(field, models.AutoField):
                del field

    def save(self, *args, **kwargs):
        with transaction.commit_on_success():
            Setting.objects.filter(domain=self.domain).delete()

            for field in self._meta.fields:
                if isinstance(field, models.ForeignKey) or isinstance(field, models.AutoField):
                    continue
                else:
                    print field.name + ': ' + field.value_to_string(self)
                    Setting.objects.create(domain=self.domain,
                        name=field.name, value=field.value_to_string(self)
                    )

This proxy has all the fields that I’d like display in my ModelFom and store as key-value pairs in my model. Now if I ever needed to add more fields, I could simply modify this abstract model and not have to edit the actual model itself. Now that I have a model, I can simply build a ModelForm on it like so:

class SettingsForm(forms.ModelForm):

    class Meta:
        model = SettingProxy
        exclude = ('domain',)

    def save(self, domain, *args, **kwargs):
        print self.cleaned_data
        commit = kwargs.get('commit', True)
        kwargs['commit'] = False
        setting = super(SettingsForm, self).save(*args, **kwargs)
        setting.domain = domain
        if commit:
            setting.save()
        return setting

I hope this helps. It required a lot of digging through the API docs to figure this out.