Detect the current Rails environment from JavaScript or CSS

Detecting if a Javascript is running under Selenium WebDriver is super-painful Show archive.org snapshot . It's much easier to detect the current Rails environment instead.

You might be better of checking against the name of the current Rails environment. To do this, store the environment name in a data-environment of your <html>. E.g., in your application layout:

<html data-environment=<%= Rails.env %>>

Now you can say in a piece of Javascript:

if (document.documentElement.dataset.environment == 'test') {
  // Code that should happen in Selenium tests
} else {
  // Code that should happen for other environments
}

Or in your CSS / Sass:

html[data-environment="test"] {
  * { text-transform: none !important; }
}

CSS: Matching against attributes and their values (or parts of them)

You probably know that you can use CSS selectors to match against elements and their attributes, such as:

a[title] { /* any <a> that has a "title" */ }
a[data-fancy="true"] { /* any <a> that has their "data-fancy" attribute set to "true" *...

How to get the hostname of the current machine in Rails or a Ruby script

Use Socket.gethostname. So for a machine whose hostname is "happycat", it will look like this:

>> Socket.gethostname
=> "happycat"

That should work right away for your Rails application. For plain Ruby, you first need to do:

requi...

Upgrading Cucumber and Capybara to the latest versions available for Rails 2

Specify these gem versions in your Gemfile:

gem 'cucumber', '~> 1.3.0'
gem 'cucumber-rails', '= 0.3.2' # max version for Rails 2
gem 'capybara', '< 2' # capybara 2+ requires Rails 3
gem 'mime-types', '< 2' # dependeny of capybara

...

Posted by Henning Koch to makandra dev (2011-08-04 10:32)

Detect the current Rails environment from JavaScript or CSS

See also

Related cards:

Introduction

2.3.8 to 2.3.9

Summary

Rails 3, 4, 5, 6