Update web locale determination, fixes sidekiq#2243

The code worked with "fr,en" but did not work with "fr-FR,fr,en"

Changes.md

@@ -8,6 +8,7 @@ HEAD
 - Web UI polling now uses Ajax to avoid page reload [#2266, davydovanton]
 - Several Web UI styling improvements [davydovanton]
 - Add Tamil, Hindi translations for Web UI [ferdinandrosario, tejasbubane]
+- Fix Web UI to work with country-specific locales [#2243]
 - Handle circular error causes [#2285,  eugenk]  
 
 3.3.3

lib/sidekiq/web_helpers.rb

@@ -45,9 +45,20 @@ def capture(&block)
       eval('', block.binding)
     end
 
+    # Given a browser request Accept-Language header like
+    # "fr-FR,fr;q=0.8,en-US;q=0.6,en;q=0.4,ru;q=0.2", this function
+    # will return "fr" since that's the first code with a matching
+    # locale in web/locales
     def locale
-      lang = (request.env["HTTP_ACCEPT_LANGUAGE"] || 'en').split(',')[0].downcase
-      strings[lang] ? lang : 'en'
+      @locale ||= begin
+        locale = 'en'.freeze
+        languages = request.env['HTTP_ACCEPT_LANGUAGE'.freeze] || 'en'.freeze
+        languages.downcase.split(','.freeze).each do |lang|
+          lang = lang.split(';'.freeze)[0]
+          break locale = lang if strings.has_key?(lang)
+        end
+        locale
+      end
     end
 
     def get_locale

test/test_web_helpers.rb

@@ -0,0 +1,46 @@
+require_relative 'helper'
+require 'sidekiq'
+require 'sidekiq/web_helpers'
+
+class TestWebHelpers < Sidekiq::Test
+
+  class Helpers
+    include Sidekiq::WebHelpers
+
+    def initialize(params={})
+      @thehash = default.merge(params)
+    end
+
+    def request
+      self
+    end
+
+    def settings
+      self
+    end
+
+    def locales
+      ['web/locales']
+    end
+
+    def env
+      @thehash
+    end
+
+    def default
+      {
+      }
+    end
+  end
+
+  def test_locale_determination
+    obj = Helpers.new
+    assert_equal 'en', obj.locale
+
+    obj = Helpers.new('HTTP_ACCEPT_LANGUAGE' => 'fr-FR,fr;q=0.8,en-US;q=0.6,en;q=0.4,ru;q=0.2')
+    assert_equal 'fr', obj.locale
+
+    obj = Helpers.new('HTTP_ACCEPT_LANGUAGE' => 'zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.4,ru;q=0.2')
+    assert_equal 'zh-cn', obj.locale
+  end
+end