rails: block ie

block_ie.md

reference: ruby-journal.com

How to Block Old IE Version With Rails

Install useragent gem by appending to Gemfile:

gem 'useragent'

then bundle install

Now we will inject a filter in ApplicationController to detect user agent. Below is the source code:

class ApplicationController < ActionController::Base

  before_filter :check_browser

  private

    Browser = Struct.new(:browser, :version)

    SupportedBrowsers = [
      Browser.new('Safari', '6.0.2'),
      Browser.new('Firefox', '19.0.2'),
      Browser.new('Internet Explorer', '9.0'),
      Browser.new('Chrome', '25.0.1364.160')
    ]

    def check_browser
      user_agent = UserAgent.parse(request.user_agent)
      unless SupportedBrowsers.detect { |browser| user_agent >= browser }
        render text: 'Your browser is not supported!'
      end
    end
end

Let’s digest what’s happening the code above.

Browsers is a Struct object with two attributes :browser and :version. This models after the way UserAgent create browser object. Pay attention to SupportedBrowsers closely, this array defines a stack of supported browsers.

check_browser will get called before any action, this method compare your current user agent with SupportedBrowsers. If the condition is not met, we render a simple text to warn the user. You could extend it to use HTML template if you like.

Please be noted that I assume all your controllers are subclass of ApplicationController. Please adapt the source code accordingly should your controllers extends different parent controller class.