Remove user_agent_parser gem, re-use browser gem

Gemfile

@@ -68,7 +68,6 @@ gem 'stringex', require: false
 gem 'strong_migrations', '>= 0.4.2'
 gem 'subprocess', require: false
 gem 'uglifier', '~> 4.2'
-gem 'user_agent_parser'
 gem 'valid_email', '>= 0.1.3'
 gem 'view_component', '~> 2.40.0', require: 'view_component/engine'
 gem 'webauthn', '~> 2.1'

Gemfile.lock

@@ -632,7 +632,6 @@ GEM
       execjs (>= 0.3.0, < 3)
     unicode-display_width (2.0.0)
     uniform_notifier (1.14.2)
-    user_agent_parser (2.7.0)
     uuid (2.3.9)
       macaddr (~> 1.0)
     valid_email (0.1.3)
@@ -792,7 +791,6 @@ DEPENDENCIES
   strong_migrations (>= 0.4.2)
   subprocess
   uglifier (~> 4.2)
-  user_agent_parser
   valid_email (>= 0.1.3)
   view_component (~> 2.40.0)
   webauthn (~> 2.1)

app/models/device.rb

@@ -14,6 +14,6 @@ def decorate
   end
 
   def device_name
-    DeviceTracking::DeviceName.call(UserAgentParser::Parser.new, self)
+    DeviceTracking::DeviceName.call(self)
   end
 end

app/services/device_tracking/device_name.rb

@@ -1,26 +1,12 @@
 module DeviceTracking
   class DeviceName
-    def self.call(parser, device)
-      device_user_agent = device.user_agent
-      user_agent = parser.parse(device_user_agent)
+    def self.call(device)
+      browser = BrowserCache.parse(device.user_agent)
       I18n.t(
         'account.index.device',
-        browser: browser(user_agent),
-        os: os(user_agent),
+        browser: "#{browser.name} #{browser.version}",
+        os: "#{browser.platform.name} #{browser.platform.version.split('.').first}",
       )
     end
-
-    def self.browser(user_agent)
-      version = user_agent.version
-      "#{user_agent.family} #{version ? version.major : ''}"
-    end
-    private_class_method :browser
-
-    def self.os(user_agent)
-      user_agent_os = user_agent.os
-      version = user_agent_os.version
-      "#{user_agent_os.family} #{version ? version.major : ''}"
-    end
-    private_class_method :os
   end
 end

app/services/device_tracking/list_devices.rb

@@ -3,9 +3,7 @@ class ListDevices
     def self.call(user_id, offset, limit)
       devices = Device.where(user_id: user_id).order(last_used_at: :desc).offset(offset).
                 limit(limit)
-      # heavy cost to load; instantiate once and parse in bulk
-      parser = UserAgentParser::Parser.new
-      devices.each { |device| device.nice_name = DeviceName.call(parser, device) }
+      devices.each { |device| device.nice_name = DeviceName.call(device) }
     end
   end
 end

spec/features/account/device_spec.rb

@@ -18,6 +18,6 @@
   end
 
   scenario 'viewing devices' do
-    expect(page).to have_content('Chrome 71 on Mac OS X 10')
+    expect(page).to have_content('Chrome 71 on macOS 10')
   end
 end

spec/services/device_tracking/device_name_spec.rb

@@ -2,11 +2,10 @@
 
 describe DeviceTracking::DeviceName do
   subject { described_class }
-  let(:parser) { UserAgentParser::Parser }
   let(:device) { create(:device) }
 
   it 'gives a shortened os and browser name' do
-    result = subject.call(parser.new, device)
+    result = subject.call(device)
 
     expect(result).to eq('Chrome 58 on Windows 10')
   end