SOLID in Ruby with working code for every principle: Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion, plus a bonus rule on minimizing nesting and a fair look at the criticisms of SOLID.
Ruby 3.2 adds new syntax for anonymous arguments: forward positional and keyword arguments with bare * and ** and unpack them inside the method, no more digging through kwargs hashes. A before-and-after example shows how much cleaner argument passing gets.
Naive Bayes classification in plain Ruby: how prior and posterior probabilities decide the winning class, then a working spam filter that classifies email titles. Also where the algorithm shines: sentiment analysis, recommendations, and fraud detection.
Rails CookieOverflow strikes when a cookie exceeds 4096 bytes. How to inspect cookies in Chrome dev tools, read the session dump on the error page, and use the cookie_debugger gem to log exactly which session key is eating the space, even in production.
ActiveRecord callbacks bring tight coupling, slower transactions, and painful debugging. Why before_save and after_save hooks in Rails models cause trouble, and how replacing them with an explicit process class makes the same flow readable and easy to debug.
Apipie looks like an easy way to document a Rails API, but check its limits first: no advanced type constraints like exactly_one_of, only partial OpenAPI support, and weak handling of output examples. What to weigh before picking the gem for a larger application.