Roda, the routing tree web toolkit: A tutorial

Roda is a Ruby web framework that emphasizes simplicity and performance by utilizing a routing tree structure, which allows for more efficient request handling compared to traditional frameworks like Ruby on Rails and Sinatra. Instead of iterating through arrays of possible routes, Roda checks each segment of a request path sequentially and only proceeds down matching branches, reducing per-request overhead. This approach not only enhances performance but also allows developers to operate on the current request at any point during routing. Roda is built on top of Rack, making it compatible with a wide range of Ruby web applications, and it remains lightweight by using plugins to extend functionality, offering over 60 built-in plugins to avoid reliance on external ones. Additionally, Roda minimizes global namespace pollution by prefixing internal instance variables and constants, increasing reliability and reducing potential conflicts with user-defined variables and constants. The framework provides methods like `r.on` and `r.is` to handle routing, enabling developers to write concise and DRY code, with the ability to execute code during routing for tasks like authentication or user lookup. Overall, Roda is designed to be a robust yet straightforward tool for web development, focusing on essential features while allowing extensibility through its plugin architecture.