Do some browser detection with Ruby. Includes ActionController integration.

gem install browser

require "browser"

browser = Browser.new("Some User Agent", accept_language: "en-us")

# General info
browser.bot?
browser.chrome?
browser.chromium_based?
browser.core_media?
browser.duck_duck_go?
browser.edge?                # Newest MS browser
browser.electron?            # Electron Framework
browser.firefox?
browser.full_version
browser.ie?
browser.ie?(6)               # detect specific IE version
browser.ie?([">8", "<10"])   # detect specific IE (IE9).
browser.known?               # has the browser been successfully detected?
browser.unknown?             # the browser wasn't detected.
browser.meta                 # an array with several attributes
browser.name                 # readable browser name
browser.nokia?
browser.opera?
browser.opera_mini?
browser.phantom_js?
browser.quicktime?
browser.safari?
browser.safari_webapp_mode?
browser.samsung_browser?
browser.to_s            # the meta info joined by space
browser.uc_browser?
browser.version         # major version number
browser.webkit?
browser.webkit_full_version
browser.yandex?
browser.wechat?
browser.qq?
browser.weibo?
browser.sputnik?
browser.sougou_browser?

# Get bot info
browser.bot.name
browser.bot.search_engine?
browser.bot?
browser.bot.why? # shows which matcher detected this user agent as a bot.
Browser::Bot.why?(ua)

# Get device info
browser.device
browser.device.id
browser.device.name
browser.device.unknown?
browser.device.blackberry_playbook?
browser.device.console?
browser.device.ipad?
browser.device.iphone?
browser.device.ipod_touch?
browser.device.kindle?
browser.device.kindle_fire?
browser.device.mobile?
browser.device.nintendo?
browser.device.playstation?
browser.device.ps3?
browser.device.ps4?
browser.device.psp?
browser.device.silk?
browser.device.surface?
browser.device.tablet?
browser.device.tv?
browser.device.vita?
browser.device.wii?
browser.device.wiiu?
browser.device.samsung?
browser.device.switch?
browser.device.xbox?
browser.device.xbox_360?
browser.device.xbox_one?

# Get platform info
browser.platform
browser.platform.id
browser.platform.name
browser.platform.version  # e.g. 9 (for iOS9)
browser.platform.adobe_air?
browser.platform.android?
browser.platform.android?(4.2)   # detect Android Jelly Bean 4.2
browser.platform.android_app?     # detect webview in an Android app
browser.platform.android_webview? # alias for android_app?
browser.platform.blackberry?
browser.platform.blackberry?(10) # detect specific BlackBerry version
browser.platform.chrome_os?
browser.platform.firefox_os?
browser.platform.ios?     # detect iOS
browser.platform.ios?(9)  # detect specific iOS version
browser.platform.ios_app?     # detect webview in an iOS app
browser.platform.ios_webview? # alias for ios_app?
browser.platform.linux?
browser.platform.mac?
browser.platform.unknown?
browser.platform.windows10?
browser.platform.windows7?
browser.platform.windows8?
browser.platform.windows8_1?
browser.platform.windows?
browser.platform.windows_mobile?
browser.platform.windows_phone?
browser.platform.windows_rt?
browser.platform.windows_touchscreen_desktop?
browser.platform.windows_vista?
browser.platform.windows_wow64?
browser.platform.windows_x64?
browser.platform.windows_x64_inclusive?
browser.platform.windows_xp?
browser.platform.kai_os?

To add aliases like mobile? and tablet? to the base object (e.g browser.mobile?), require the browser/aliases file and extend the Browser::Base object like the following:

require "browser/aliases"
Browser::Base.include(Browser::Aliases)

browser = Browser.new("Some user agent")
browser.mobile? #=> false

• For a list of platform detections, check lib/browser/platform.rb
• For a list of device detections, check lib/browser/device.rb
• For a list of bot detections, check bots.yml

To detect whether a browser can be considered as modern or not, create a method that abstracts your versioning constraints. The following example will consider any of the following browsers as a modern:

# Expects an Browser instance,
# like in `Browser.new(user_agent, accept_language: language)`.
def modern_browser?(browser)
  [
    browser.chrome?(">= 65"),
    browser.safari?(">= 10"),
    browser.firefox?(">= 52"),
    browser.ie?(">= 11") && !browser.compatibility_view?,
    browser.edge?(">= 15"),
    browser.opera?(">= 50"),
    browser.facebook?
      && browser.safari_webapp_mode?
      && browser.webkit_full_version.to_i >= 602
  ].any?
end

Just add it to the Gemfile.

gem "browser"

This adds a helper method called browser, that inspects your current user agent.

<% if browser.ie?(6) %>
  <p class="disclaimer">You're running an older IE version. Please update it!</p>
<% end %>

If you want to use Browser on your Rails app but don't want to taint your controller, use the following line on your Gemfile:

gem "browser", require: "browser/browser"

Parses the accept-language header from an HTTP request and produces an array of language objects sorted by quality.

browser = Browser.new("Some User Agent", accept_language: "en-us")

browser.accept_language.class
#=> Array

language = browser.accept_language.first

language.code
#=> "en"

language.region
#=> "US"

language.full
#=> "en-US"

language.quality
#=> 1.0

language.name
#=> "English/United States"

Result is always sorted in quality order from highest to lowest. As per the HTTP spec:

• omitting the quality value implies 1.0.
• quality value equal to zero means that is not accepted by the client.

Internet Explorer has a compatibility view mode that allows newer versions (IE8+) to run as an older version. Browser will always return the navigator version, ignoring the compatibility view version, when defined. If you need to get the engine's version, you have to use Browser#msie_version and Browser#msie_full_version.

So, let's say an user activates compatibility view in a IE11 browser. This is what you'll get:

browser.version
#=> 11

browser.full_version
#=> 11.0

browser.msie_version
#=> 7

browser.msie_full_version
#=> 7.0

browser.compatibility_view?
#=> true

This behavior changed in v1.0.0; previously there wasn't a way of getting the real browser version.

iOS webviews and web apps aren't detected as Safari anymore, so be aware of that if that's your case. You can use a combination of platform and webkit detection to do whatever you want.

# iPad's Safari running as web app mode.
browser = Browser.new("Mozilla/5.0 (iPad; U; CPU OS 3_2_1 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Mobile/7B405")

browser.safari?
#=> false

browser.webkit?
#=> true

browser.platform.ios?
#=> true

The bot detection is quite aggressive. Anything that matches at least one of the following requirements will be considered a bot.

• Empty user agent string
• User agent that matches /crawl|fetch|search|monitoring|spider|bot/
• Any known bot listed under bots.yml

To add custom matchers, you can add a callable object to Browser::Bot.matchers. The following example matches everything that has a externalhit substring on it. The bot name will always be General Bot.

Browser::Bot.matchers << ->(ua, _browser) { ua.match?(/externalhit/i) }

To clear all matchers, including the ones that are bundled, use Browser::Bot.matchers.clear. You can re-add built-in matchers by doing the following:

Browser::Bot.matchers += Browser::Bot.default_matchers

To restore v2's bot detection, remove the following matchers:

Browser::Bot.matchers.delete(Browser::Bot::KeywordMatcher)
Browser::Bot.matchers.delete(Browser::Bot::EmptyUserAgentMatcher)

To extend the bot list, you can manipulate the methods below:

Browser::Bot.bots.merge!(new_bots_hash)
Browser::Bot.bot_exceptions += new_exceptions
Browser::Bot.search_engines.merge!(new_search_engines_hash)

You can use the Browser::Middleware to redirect user agents.

use Browser::Middleware do
  redirect_to "/upgrade" if browser.ie?
end

If you're using Rails, you can use the route helper methods. Just add something like the following to a initializer file (config/initializers/browser.rb).

Rails.configuration.middleware.use Browser::Middleware do
  redirect_to upgrade_path if browser.ie?
end

If you need access to the Rack::Request object (e.g. to exclude a path), you can do so with request.

Rails.configuration.middleware.use Browser::Middleware do
  redirect_to upgrade_path if browser.ie? && request.env["PATH_INFO"] != "/exclude_me"
end

• User agent has a size limit of 2048 bytes. This can be customized through Browser.user_agent_size_limit=(size).
• Accept-Language has a size limit of 2048 bytes. This can be customized through Browser.accept_language_size_limit=(size).

If size is not respected, then Browser::Error is raised.

Browser.user_agent_size_limit = 4096
Browser.accept_language_size_limit = 4096

This library follows http://semver.org.

Once you've made your great commits (include tests, please):

1. Fork browser
2. Create a topic branch - git checkout -b my_branch
3. Push to your branch - git push origin my_branch
4. Create a pull request
5. That's it!

Please respect the indentation rules and code style. And use 2 spaces, not tabs. And don't touch the version thing.

To configure your environment, you must have Ruby and bundler installed. Then run bundle install to install all dependencies.

To run tests, execute ./bin/rake.

Before using your time to code a new feature, open a ticket asking if it makes sense and if it's on this project's scope.

Don't forget to add a new entry to CHANGELOG.md.

1. Add the user agent to test/ua_bots.yml.
2. Add the readable name to bots.yml. The key must be something that matches the user agent, in lowercased text.
3. Run tests.

Don't forget to add a new entry to CHANGELOG.md.

1. Add the user agent to test/ua_search_engines.yml.
2. Add the same user agent to test/ua_bots.yml.
3. Add the readable name to search_engines.yml. The key must be something that matches the user agent, in lowercased text.
4. Run tests.

Don't forget to add a new entry to CHANGELOG.md.

If you know how to fix it, follow the "Writing code" above. Open an issue otherwise; make sure you fill in the issue template with all the required information.

• Nando Vieira - https://nandovieira.com

• https://github.com/fnando/browser/contributors

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.