How to Use a Variable with extends in Django Templates

Discover how to dynamically manage templates in Django using variables. Solve the `TemplateDoesNotExist` error effectively with our step-by-step guide.
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Managing Dynamic Templates in Django: A Step-by-Step Guide

Django is a powerful web framework that allows developers to create dynamic web applications with ease. However, when it comes to using variables within Django templates, especially for managing themes or dynamic templates, things can get a bit tricky. If you've faced the issue of extending templates using variables, you're not alone. In this guide, we'll clarify this problem and present a robust solution.

The Problem: Using Variables in Template Inheritance

Imagine you have a Django project where you want to switch themes dynamically based on a variable defined in your settings.py. You might set up a variable like this:

[[See Video to Reveal this Text or Code Snippet]]

Now, suppose you tried to create a dynamic template by using this variable within an extends tag in your Django template like this:

[[See Video to Reveal this Text or Code Snippet]]

When you run your Django application, you may encounter the following error:

[[See Video to Reveal this Text or Code Snippet]]

This error indicates that Django is trying to resolve the template path literally with the double curly braces instead of substituting the ACTIVE_TEMPLATE variable. So, how do we fix this?

The Solution: Using Add Filter

To correctly use a variable in your extends statement, you can utilize Django's built-in template filters. Specifically, you can use the add filter to concatenate strings. By modifying your extends tag like this:

[[See Video to Reveal this Text or Code Snippet]]

How It Works:

"frontend/"|add:ACTIVE_TEMPLATE: Here, you're starting with the string "frontend/" and concatenating the value of ACTIVE_TEMPLATE. If ACTIVE_TEMPLATE is "presento", this part resolves to "frontend/presento".

|add:"/base/base.html": Then, you're adding the remaining path to form the complete template string.

By employing the add filter, Django will properly resolve the entire path to the template file, preventing the TemplateDoesNotExist error.

Summary

Managing dynamic templates in Django is straightforward once you know how to properly utilize template variables. Instead of directly using the double curly braces {{ }}, which Django does not evaluate in this context, you can concatenate strings using the add filter to build your template path dynamically.

Key Takeaways:

Define your dynamic template variable in settings.py.

Use the add filter to build template paths dynamically in your Django templates.

Avoid using double curly braces within the extends tag for template inheritance.

By following these steps, you'll be able to leverage Django's flexibility in managing themes and templates more effectively. Happy coding!

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