1. Introduction

This tutorial aims to introduce Django's built-in middleware and explore components that are specifically tailored to improve security and performance. Middleware in Django is a series of hooks into Django's request/response processing. It's a light, low-level "plugin" system for globally altering Django's input or output.

By the end of this tutorial, you will learn how to use Django's built-in middleware for security and optimization, understand when and why to use them, and be able to implement them in your projects.

Prerequisites: Basic understanding of Django and Python, and a setup Django project environment.

2. Step-by-Step Guide

Middleware is a framework of hooks into Django’s request/response processing. It's a light, low-level “plugin” system for globally altering Django’s input or output. Django’s built-in middleware classes provide solutions to various challenges such as security, session management, and caching.

Enable middleware by setting them in the MIDDLEWARE setting in the Django settings.py file. They are processed in the order they are defined, from top to bottom.

3. Code Examples

Here are a few examples of Django's built-in middleware:

SecurityMiddleware

Django's SecurityMiddleware provides several security enhancements:

MIDDLEWARE = [
    ...
    'django.middleware.security.SecurityMiddleware',
    ...
]

This middleware activates several security enhancements:
- It manages the X-Content-Type-Options header, which prevents browsers from MIME-sniffing a response away from the declared content-type.
- If SECURE_BROWSER_XSS_FILTER is True, it sets the X-XSS-Protection header, enabling the browser's XSS filtering protections.
- If SECURE_CONTENT_TYPE_NOSNIFF is True, it sets the X-Content-Type-Options header to nosniff, instructing the browser not to sniff the content type.

GZipMiddleware

Django's GZipMiddleware compresses content for browsers that understand GZip compression (all modern browsers). This can dramatically reduce the bandwidth required for your site.

MIDDLEWARE = [
    ...
    'django.middleware.gzip.GZipMiddleware',
    ...
]

This middleware should be placed as high as possible, especially before any middleware that can generate responses.

4. Summary

In this tutorial, we've covered how to use Django's built-in middleware for security and performance optimization. We've learned how to use SecurityMiddleware for security enhancements and GZipMiddleware to compress content.

Continue learning by exploring other built-in middleware like SessionMiddleware, CsrfViewMiddleware, AuthenticationMiddleware, and more.

5. Practice Exercises

1. Enable SecurityMiddleware in your Django project and set SECURE_BROWSER_XSS_FILTER to True.
2. Enable GZipMiddleware in your Django project and test the difference in the size of your site's response.

Solutions:
1. In your settings.py file, add 'django.middleware.security.SecurityMiddleware', to your MIDDLEWARE setting. Then, set SECURE_BROWSER_XSS_FILTER = True.
2. Add 'django.middleware.gzip.GZipMiddleware', to your MIDDLEWARE setting. Compare your site's response size before and after enabling this middleware by inspecting the network tab in your browser's developer tools.

Remember to place your middleware in the correct order in the MIDDLEWARE setting. In general, these should be placed towards the top of the list.