Ruby

When I first started using model concerns I struggled with how I could test the functionality of the concern, without having to replicate the tests across all models. Here I show you how I decided to test model concerns. It may be controversial, so buckle up. What are Model Concerns? Model concerns are an interesting concept that — if I recall correctly— debuted with Rails 4. They allow a developer to refactor common functionality out from various models and centralize it into a module, called a concern. A non-contrived example of this shows how several of my models can be deactivated at any time. ...

Note: This article assumes a working knowledge of rbenv. Installing rbenv (a Ruby version manager) on a Raspbian-based Raspberry Pi is a bit difficult because the base Debian ruby-build package does not provide you with an up-to-date list of Ruby versions. To workaround this issue, you can easily install ruby-build yourself, instead of relying on the official Debian packages. I’m not a fan of the official rbenv package in the Debian repositories because it tries to install too many things (namely Ruby 1.8 for some reason), and I also don’t like to install rbenv system-wide, so let’s start by installing rbenv to our local user. ...

Here is a quick tip on how to install the pg ruby gem on OSX if you only have Postgres.app installed. First, if you attempt to install the pg gem it will fail with: $ gem install pg Fetching: pg-0.17.1.gem (100%) Building native extensions. This could take a while... ERROR: Error installing pg: ERROR: Failed to build gem native extension. /Users/me/.rbenv/versions/2.1.5/bin/ruby extconf.rb checking for pg_config... no No pg_config... trying anyway. If building fails, please try again with --with-pg-config=/path/to/pg_config checking for libpq-fe.h... no Can't find the 'libpq-fe.h header *** extconf.rb failed *** If you search for solutions to this issue you will undoubtedly be told to install the postgresql package from Homebrew. That’s nice, but you already have the Postgres.app and you don’t want to maintain 2 versions of the same application on your machine (it is also not isolated, and can cause port conflicts). ...

Note: Contrary to what you are about to read, I am still against metaprogramming on the whole, as it adds an unnecessary amount of magic that may confuse other developers. That being said, I would hate working in a language without it. Use sparingly, like junk food. “With great power…” Yadda yadda. Enjoy the article. I am currently writing a gem to wrap the Cleanspeak API and I was using the JSON examples in my test cases that they supply in their API docs. I wrote the test cases like so: ...

In honour of our friends down South celebrating their independence, let’s look at installing a local version of ruby onto a POSIX machine without requiring wrappers like rvm or rbenv. We want to be free to install things where we want, when we want, and how we want. Now that’s true freedom. Install GNU Stow Okay, you are going to need to install stow system wide for this step. This requires administrative permissions. I promise it’s the only thing. ...

A new framework crossed my radar on HackerNews today called Lotus. It is based on Ruby and attempts to adhere to proper OO principles. It looks simple to learn so I thought I’d give it a try. I ran into a few issues with the first example in the docs provided in the Github project, so I’ll post some fixes. This is running version 0.1.0 of the lotusrb gem. # config.ru require 'lotus' module OneFile class Application < Lotus::Application configure do routes do get '/', to: 'home#index' end end end module Controllers::Home include OneFile::Controller action 'Index' do def call(params) end end end module Views::Home class Index include OneFile::View def render 'Hello' end end end end run OneFile::Application.new If you paste that into a file called config.ru, you can then run it with rack: ...

I attended BSides Vancouver last week (great job everyone!) and Mark Curphey had a good talk (Modern Software is Like Lego & WTF Don’t People Use Secure Headers?) containing a statistic on how few websites use secure headers. His company even came up with a Web-based tool to find which websites contain secure headers. I love this idea but I found it lacked in one area: testing sites not publicly addressable on the Web. There are many more internal websites that could be sniffed or exploited inside company networks. So I went about writing a tool called tinfoil that allows anyone to check servers within their network. ...

I’m writing up a new gem called Tinfoil that tests whether web servers support secure headers. Since this is a command-line interface (CLI) for a Unix-based system, I have a hard time testing the CLI in Ruby’s built-in Test::Unit framework. The problem is that the CLI outputs directly to STDOUT and STDERR, polluting my test output when I run them. The problem to this was solved by capturing stdout and stderr and redirecting them for a short time while the test runs. I got it from this StackOverflow answer, and I have added another method for capturing stderr. ...

One of the things that I dislike about Rails is how some actions feel untestable. Take, for example, the act of grabbing the current user. This is bog-standard code that you’d see in a lot of Rails tutorials and people’s codebases. What I don’t like about it is that the current_user method is not easily testable. Heck, which test file do you put the tests in? ...

When people have looked at my code, specifically my test code, one of the most common things they ask is why I test my getters and setters. They see this as a weird thing to do, but I tend to be a very paranoid defensive programmer, so I like to ensure that my getters and setters aren’t actually modifying anything. “That is paranoid, Scott” you proclaim, and try to enlighten me on all the code that doesn’t modify accessor methods. But I’ve been burned by this assumption often, and a simple and stupid unit test ensures that the code is adhering to my assumptions. It’s quick and painless. ...