What are the differences between Rails 5 and Rails 6?

Here’s an overview of the key differences between Rails 5 and Rails 6 from the perspective of a professional Python developer:

Rails 6 brought several enhancements and new modules over Rails 5, emphasizing better performance, scalability, and developer experience:

1. Action Mailbox: Rails 6 introduced Action Mailbox, which streamlines the management of incoming emails. It’s capable of routing inbound emails to appropriate mailbox classes, making email handling in Rails more structured.

2. Action Text: This is a new framework in Rails 6 that incorporates the Trix editor, facilitating rich text content creation and management. It seamlessly integrates WYSIWYG editing with Active Record models.

3. Parallel Testing: A significant boost in Rails 6 is the ability to run tests in parallel by default, utilizing multiple processor cores. This can lead to much faster test suite run times, especially beneficial for large applications.

4. Multiple Database Support: Rails 6 brings native support for multiple databases, allowing developers to easily set up, manage, and switch between different databases within the same application.

5. Webpacker Default: In Rails 6, Webpacker became the default JavaScript compiler, signifying a move towards modern JavaScript tooling and away from the traditional Sprockets-based asset pipeline.

6. Zeitwerk Mode: Rails 6 introduced Zeitwerk, a new code loader that offers efficient and thread-safe constant autoloading. This means fewer issues related to autoloading in the development environment.

7. Action Cable Enhancements: Rails 6 improved Action Cable by adding support for testing and introducing connection handling in a more organized manner.

8. Security and Blocked Hosts: Rails 6 added a security feature where requests to unknown or unauthorized hosts can be blocked, reducing the risk of host header injection attacks.

9. Enhancements and Deprecations: Beyond major features, Rails 6 also brought about a plethora of minor enhancements, optimizations, and a few deprecations to streamline the framework further and lay the groundwork for future iterations.

While Rails 5 provided a solid foundation, Rails 6 built upon it by adding powerful new features, optimizing existing functionalities, and enhancing the overall developer experience. It reflects the Rails community’s commitment to adapt to the evolving landscape of web development.