django

[Django] String Labels in Site: Use Key-Value Pairs Model & Form

This article is to make a model used to save string label in site (e.g. site_title), like this:

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class Label(models.Model):
    key = models.CharField(max_length=32, primary_key=True)
    value = models.CharField(max_length=128,blank=True, default='')

And, make a form like this to update it:

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Site Configuration
site_title: ________________
site_subtitle: _________________
site_copyright_info: _________________
admin_email: _________________
admin_phone: _________________
[Save]

There are some package like jezdez/django-constance to do this task, but I would rather not to use too many 3rd part package in project. Though, I use django-crispy-forms.

settings.py

Define your labels in settings.py:

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LABELS = [
    # ('key', 'label in form', 'default value'),
    ('site_title'     , 'Site Title',     'Hello World!'),
    ('copyright_info' , 'Copyright Info', 'John Smith (c) 2015'),
    ('admin_email'    , 'Your E-mail',    '02 1234 5678'),
]

models.py

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from django.conf import settings
from django.db import models

class Label(models.Model):
    key = models.CharField(max_length=32, primary_key=True)
    value = models.CharField(max_length=128,blank=True, default='')

    @classmethod
    def get_label(cls, key):
        
        """Get the value of a label via key.
        If not found, create one with the default value in
        settings.LABELS."""
        
        try:
            return cls.objects.get(key=key).value
        except:
            default_value = [x for x in settings.LABELS if x[0] == key][0]
            cls.objects.create(key=key, value=default_value)
            return default_value

forms.py

We define save() method to save request.POST into our model.

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from django import forms
from pages.models import Label
from django.conf import settings

from crispy_forms.helper import FormHelper
from crispy_forms.layout import Submit, Layout, Div, Button, Fieldset, HTML

class LabelForm(forms.Form):    

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        for key, label, default_value in settings.LABELS: # settings.LABELS
            self.fields[key] = forms.CharField(max_length=128)
            self.fields[key].label = label

            # get_or_create => (<Label: Label object>, False)
            labelObj, _ = Label.objects.get_or_create(
                key=key,
                defaults={'value': default_value})
            self.fields[key].initial = labelObj.value

        self.helper = FormHelper()
        self.helper.add_input(Submit('submit', 'Submit'))
        
    def save(self, POST):
        for key, _, _ in settings.LABELS:
            Label.objects.filter(key=key).update(value=POST[key])

views.py

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from pages.models import Label
from pages.forms import LabelForm

class LabelSettings(FormView):

    template_name = "label_settings.html"
    form_class = LabelForm
    success_url = '.'   # whatever.
    
    def form_valid(self, form):
        super().form_valid(form)
        form.save(self.request.POST)   # pass POST dict to LabelForm.save()
        return HttpResponseRedirect(self.get_success_url())

label_settings.html

This page is used to edit/save our labels.

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<form method="post" action="">
  {% crispy form %}
</form>

How To Use In Template?

templatetags/common_tags.py

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from django import template
from pages.models import Label
register = template.Library()

@register.simple_tag
def label(key):
    return Label.get_label(key)

Now, we can use it!

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{% load common_tags %}
<h1>{% label 'site_title' %}</h1>