Rails for Villains

In this series, I’m going to talk about Rails. But I’m also going to talk about myself; it’s rare for a person to just stumble into being a developer. Some of the people I’ve met along the way have stories about how their first computer was some amazingly archaic device, and they’ll talk about how they used it to invent their own programming language, or, like, create some sort of magical game, or world.

Ok, now, let’s do something useful, and talk about the rails console. I’ve created a very simple Rails application, using ruby version 2.5.1, and rails 5.2.4.3. This shouldn’t matter, because I’m not doing anything special, but who knows.. maybe these commands won’t work for you, and knowing the versions will help. rails new rails_for_villains cd rails_for_villains rails g migration createEnemies I edited the generated file, so that the model I create would contain only the ‘updated_at’ and ‘created_at’ timestamps, like so:

The Plan He entered the trailer and set his satchel, heavy with sample books, down by the door. Sighing, he walked into the kitchen. His wife, eight months pregnant, looked upset. Thin, even in pregnancy, she was beautiful, with long, thick brown hair, and thick horn-rimmed glasses. “I visited the hospital today, they say it’s going to cost five thousand dollars, to give birth at there.” “What? That’s highway robbery. We’ll do it at home.

Rails has a concept called ‘convention over configuration’. In theory, this means that, by following conventions, we can accomplish a lot of work, without having to spend very much time configuring very much at all. In practice, it means that, generally, it’s not obvious what’s happening, especially to a Rails newbie. This can be confusing, but it works through a concept called metaprogramming. Metaprogramming means that, rather than creating a lot of boilerplate code, rails will follow general conventions to automatically create a lot of functionality for us, in the form of methods that are created at runtime, and so only exist in active memory, in a running Rails application.

Here, we are going to create a situation where we can see what new methods are created in Rails, when a new field is added to a table. To accomplish this, we can use two consoles. One will be a simple command line, and the other will be a rails console. In the first console, it’s important to stay logged in; we’re going to capture the list of methods on the ‘enemy’ table, before and after a migration, so that we can easily see the difference, and run a migration in the second console, to actually add a field to the database.

Caleb is on a farm. Five acres of woods, fences, and buildings. He’s six years old. He’s got a lot of time on his hands. He climbs on top of every building, and invents obstacle courses to run. Climb the outside of the ‘train car’, a rectangular hay barn, then jump into the hay. Roll down, climb the pig pen, jump off the side, do the same to at the chicken coop.