Introduce caching to circumvent issue with using UserAgentParser.parse

lib/user_agent_parser.rb

@@ -3,12 +3,14 @@
 require 'user_agent_parser/version'
 require 'user_agent_parser/operating_system'
 require 'user_agent_parser/device'
+require 'user_agent_parser/cache'
 
 module UserAgentParser
   DefaultPatternsPath = File.join(File.dirname(__FILE__), "../vendor/ua-parser/regexes.yaml")
+  DefaultCache = Cache.new
 
   # Parse the given +user_agent_string+, returning a +UserAgent+
   def self.parse(user_agent_string, options={})
-    Parser.new(options).parse(user_agent_string)
+    DefaultCache.fetch(options).parse(user_agent_string)
   end
 end

lib/user_agent_parser/cache.rb

@@ -0,0 +1,17 @@
+module UserAgentParser
+  class Cache
+    def initialize
+      @registry = {}
+    end
+
+    def fetch(options)
+      @registry.fetch(options.hash) do
+        add(options)
+      end
+    end
+
+    def add(options)
+      @registry[options.hash] = Parser.new(options)
+    end
+  end
+end

lib/user_agent_parser/parser.rb

@@ -1,7 +1,7 @@
 require 'yaml'
 
 module UserAgentParser
-  
+
   class Parser
     attr_reader :patterns_path
 

spec/cache_spec.rb

@@ -0,0 +1,19 @@
+require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
+
+describe UserAgentParser::Cache do
+  def custom_patterns_path
+    File.join(File.dirname(__FILE__), "custom_regexes.yaml")
+  end
+
+  it 'stores and returns the parser based on options' do
+    cache = UserAgentParser::Cache.new
+    cached_path = cache.fetch(:patterns_path => UserAgentParser::DefaultPatternsPath).patterns_path
+    cached_path.must_equal UserAgentParser::DefaultPatternsPath
+  end
+
+  it 'defaults to the default parser' do
+    cache = UserAgentParser::Cache.new
+    cached_path = cache.fetch(:patterns_path => custom_patterns_path).patterns_path
+    cached_path.must_equal custom_patterns_path
+  end
+end

spec/custom_regexes.yaml

@@ -14,4 +14,4 @@ os_parsers:
 
 device_parsers:
   - regex: '.*'
-    device_replacement: 'Custom device'
+    device_replacement: 'Custom device'

spec/parser_spec.rb

@@ -59,6 +59,7 @@ def custom_patterns_path
       ua = UserAgentParser.parse("Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en-us) AppleWebKit/418.8 (KHTML, like Gecko) Safari/419.3")
       ua.family.must_equal("Safari")
     end
+
     it "accepts a custom patterns path" do
       ua = UserAgentParser.parse("Any user agent string", :patterns_path => custom_patterns_path)
       ua.family.must_equal("Custom browser")