Using Variables in your project

Introduction

This article describes how to use variables created with the django-content-settings module in various contexts such as code, templates, and API.

Creating a Variable

Let's start by creating a MAX_PRICE variable, which we will use for price validation:

from content_settings.types.basic import SimpleDecimal

MAX_PRICE = SimpleDecimal("9.99", help="maximum allowed price in the store")

By default, if not altered in the admin panel, MAX_PRICE will return Decimal("9.99").

Usage in Python Code

Variables are accessible via content_settings located in content_settings.conf.

Example

from decimal import Decimal
from content_settings.conf import content_settings

def update_price(request):
    new_price = Decimal(request.POST["price"])
    if new_price > content_settings.MAX_PRICE:
        raise ValueError("Price is too high")

    # ...

Using Lazy Objects

In cases where a variable is used in class or function attributes, you should use a lazy object with a lazy__ prefix:

from decimal import Decimal
from content_settings.conf import content_settings

def update_price(request, max_price=content_settings.lazy__MAX_PRICE):
    new_price = Decimal(request.POST["price"])
    if new_price > max_price:
        raise ValueError("Price is too high")

    # ...

Accessing Variable Type

To get a reference to the variable type, use the type__ prefix:

content_settings.type__MAX_PRICE.fetch_permission

Access in Templates

Using variables in templates is straightforward. If you've added content_settings.context_processors.content_settings to your context_processors, you can access content_settings.conf.content_settings using {{CONTENT_SETTINGS}}.

<b>Max Price:</b> {{ CONTENT_SETTINGS.MAX_PRICE }}

Access Through API

If you've included content_settings.urls in your urls.py, it might look like this:

from django.urls import path, include
from django.contrib import admin

urlpatterns = [
    path("admin/", admin.site.urls),
    path("books/", include("books.urls")),
    path("content-settings/", include("content_settings.urls")),
]

The API allows only read access to data. By default, variables are not accessible through the API. To make a variable available, add the fetch_permission attribute:

from content_settings.types.basic import SimpleText
from content_settings import permissions

DESCRIPTION = SimpleText(
    "The best book store in the world",
    fetch_permission=permissions.any,
)

Fetching Variables via API

For example, to fetch the DESCRIPTION variable:

curl http://127.0.0.1:8000/content-settings/fetch/description/

The result will be in JSON format:

{"DESCRIPTION": "The best book store in the world"}

Fetching Multiple Variables

Use the content_settings.views.FetchSettingsView view for fetching multiple attributes:

from django.urls import path
from content_settings.views import FetchSettingsView


urlpatterns = [
    path("fetch/main/", FetchSettingsView.as_view(attrs=[
        "TITLE",
        "BOOKS__available_names",
    ]), name="fetch_main"),
    path("fetch/home-detail/", FetchSettingsView.as_view(attrs=[
        "DESCRIPTION",
        "OPEN_DATE",
        "TITLE",
    ]), name="fetch_home_detail"),
]

Fetching the group home-detail via API:

curl http://127.0.0.1:8000/content-settings/fetch/home-detail/

The result will be:

{
    "DESCRIPTION": "The best book store in the world",
    "TITLE": "Book Store"
}

When requesting a group, permissions for each variable are checked separately, and if insufficient, the variable will not be included in the response.