How to implement your own Struct class in Ruby? Metaprogramming in Ruby, part 2.

You probably already know Ruby class Struct. It allows you to create a simple class with the properties that were passed as arguments to its initializer. Also, it will run a block that was passed to its initializer within the newly created class'es scope thus allowing you to define methods, etc. Let's try to implement …

Metaprogramming in Ruby, part 1

I decided to challenge myself to write code similar to what can be found in every Rails application.rb file. TestApp::Application.configure do # Settings specified here will take precedence over those in config/application.rb # Code is not reloaded between requests config.cache_classes = true # Full error reports are disabled and caching is turned on config.consider_all_requests_local = …

has_many + scope + counter cache

I wrote this blog post partly for myself so I can have a reference for the future and also for other people who might jump into a similar problem and need a solution for it. In my current project I needed to display Users's Questions that have been answered by other users. My set up …

Scraping: Codewars Top 500 Users

Today I decided to practice my coding skills and took the time to solve one of the Kata challenges "Scraping: Codewars Top 500 Users". So here's my solution. Let me know your comments or thoughts. Note, that Codewars wanted a 1 based index array of Users. I have no clue why. I think this adds …

Dynamically fading flash messages in Vue.js and VueX

We will be creating dynamcally fading flash messages with Vue.js and VueX. Let's say you want to display a flash message on a certain condition and you want that flash to show only for a couple of seconds and disappear afterwords. It is very easy to implement it yourself within a minute without any 3rd …

Ruby detective #1 – Singleton Class

I decided to challenge myself with a series of topic about Ruby. The first series is "method lookup". Let's look at an example class. Here I define a simple class Robot which has an instance method 'say_hello' and a class method 'droids' which finds all robots of type 'droid'. Obviously '.droids' method is not there …

How to setup a Rails app with Sendgrid

In order to setup your Rails app with Sendgrid, this is the necessary configuration you need. Store username and password in environment variables. Create initializers/environment_variables.rb Create config/environment_variables.yml In config/environments/#{Rails.env}.rb In config/environment.rb Restart the server and you are good to go.

How to implement Rails params from the ground up in Ruby?

Hi guys! This time around I am going to show you how to implement Rails params completely from the ground up. As you probably already know, Rails has something called strong parameters. This is a security practice to prevent accidentally allowing users to update sensitive model attributes, for example "admin" flag in user model in …

How to implement Rails validations from scratch in Ruby

Hi guys! This time I am going to show you how to implement your own Rails validations completely from the ground up. I will talk about validations briefly, I will show you a bit of Rails source code and then show you how you can implement your own Rails validations. In Rails, every model inherits …

Rails counter cache

Let's say you have an application similar to Twitter where you have Users and Tweets and User 'has_many' tweets and Tweet 'belongs_to' user and you want to display how many Tweets a User has or how many people follow his Tweets. Typically, what you would do is query users and count their Tweets in by …