Use frozen string literal to reduce number of string allocation

Gemfile

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 source 'https://rubygems.org'
 
 # Specify your gem's dependencies in link_thumbnailer.gemspec

Rakefile

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'bundler/gem_tasks'
 require 'rspec/core/rake_task'
 

lib/generators/link_thumbnailer/install_generator.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module Generators
     class InstallGenerator < ::Rails::Generators::Base

lib/generators/templates/initializer.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # Use this hook to configure LinkThumbnailer bahaviors.
 LinkThumbnailer.configure do |config|
   # Numbers of redirects before raising an exception when trying to parse given url.

lib/link_thumbnailer.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'json'
 require 'link_thumbnailer/version'
 require 'link_thumbnailer/configuration'

lib/link_thumbnailer/configuration.rb

@@ -1,70 +1,71 @@
-module LinkThumbnailer
-
-  # Access point for the gem configurations.
-  #
-  # @return [LinkThumbnailer::Configuration] a configuration instance.
-  def self.config
-    @config ||= Configuration.new
-  end
-
-  # Configure hook used in the gem initializer. Convinient way to set all the
-  # gem configurations.
-  #
-  # @example inside config/initializers/link_thumbnaler.rb
-  #   LinkThumbnailer.configure do |config|
-  #     config.user_agent = 'link_thumbnailer'
-  #   end
-  #
-  # @return [void]
-  def self.configure
-    yield config if block_given?
-  end
-
-	class Configuration
-
-    attr_accessor :redirect_limit, :blacklist_urls, :user_agent,
-                  :verify_ssl, :http_open_timeout, :http_read_timeout, :attributes,
-                  :graders, :description_min_length, :positive_regex, :negative_regex,
-                  :image_limit, :image_stats, :raise_on_invalid_format, :max_concurrency,
-                  :scrapers, :http_override_headers, :encoding
-
-    alias_method :http_timeout, :http_open_timeout
-    alias_method :http_timeout=, :http_open_timeout=
-
-    # Create a new instance.
-    #
-    # @return [LinkThumbnailer::Configuration]
-    def initialize
-      @redirect_limit         = 3
-      @user_agent             = 'link_thumbnailer'
-      @verify_ssl             = true
-      @http_open_timeout      = 5
-      @http_read_timeout      = 5
-      @blacklist_urls         = [
-        %r{^http://ad\.doubleclick\.net/},
-        %r{^http://b\.scorecardresearch\.com/},
-        %r{^http://pixel\.quantserve\.com/},
-        %r{^http://s7\.addthis\.com/}
-      ]
-      @attributes             = [:title, :images, :description, :videos, :favicon]
-      @graders                = [
-        ->(description) { ::LinkThumbnailer::Graders::Length.new(description) },
-        ->(description) { ::LinkThumbnailer::Graders::HtmlAttribute.new(description, :class) },
-        ->(description) { ::LinkThumbnailer::Graders::HtmlAttribute.new(description, :id) },
-        ->(description) { ::LinkThumbnailer::Graders::Position.new(description, weigth: 3) },
-        ->(description) { ::LinkThumbnailer::Graders::LinkDensity.new(description) },
-      ]
-      @description_min_length = 50
-      @positive_regex = /article|body|content|entry|hentry|main|page|pagination|post|text|blog|story/i
-      @negative_regex = /combx|comment|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget|modal/i
-      @image_limit    = 5
-      @image_stats    = true
-      @raise_on_invalid_format = false
-      @max_concurrency = 20
-      @scrapers = [:opengraph, :default]
-      @http_override_headers = { 'Accept-Encoding' => 'none' }
-      @encoding = 'utf-8'
-    end
-
-	end
-end
+# frozen_string_literal: true
+module LinkThumbnailer
+
+  # Access point for the gem configurations.
+  #
+  # @return [LinkThumbnailer::Configuration] a configuration instance.
+  def self.config
+    @config ||= Configuration.new
+  end
+
+  # Configure hook used in the gem initializer. Convinient way to set all the
+  # gem configurations.
+  #
+  # @example inside config/initializers/link_thumbnaler.rb
+  #   LinkThumbnailer.configure do |config|
+  #     config.user_agent = 'link_thumbnailer'
+  #   end
+  #
+  # @return [void]
+  def self.configure
+    yield config if block_given?
+  end
+
+	class Configuration
+
+    attr_accessor :redirect_limit, :blacklist_urls, :user_agent,
+                  :verify_ssl, :http_open_timeout, :http_read_timeout, :attributes,
+                  :graders, :description_min_length, :positive_regex, :negative_regex,
+                  :image_limit, :image_stats, :raise_on_invalid_format, :max_concurrency,
+                  :scrapers, :http_override_headers, :encoding
+
+    alias_method :http_timeout, :http_open_timeout
+    alias_method :http_timeout=, :http_open_timeout=
+
+    # Create a new instance.
+    #
+    # @return [LinkThumbnailer::Configuration]
+    def initialize
+      @redirect_limit         = 3
+      @user_agent             = 'link_thumbnailer'
+      @verify_ssl             = true
+      @http_open_timeout      = 5
+      @http_read_timeout      = 5
+      @blacklist_urls         = [
+        %r{^http://ad\.doubleclick\.net/},
+        %r{^http://b\.scorecardresearch\.com/},
+        %r{^http://pixel\.quantserve\.com/},
+        %r{^http://s7\.addthis\.com/}
+      ]
+      @attributes             = [:title, :images, :description, :videos, :favicon]
+      @graders                = [
+        ->(description) { ::LinkThumbnailer::Graders::Length.new(description) },
+        ->(description) { ::LinkThumbnailer::Graders::HtmlAttribute.new(description, :class) },
+        ->(description) { ::LinkThumbnailer::Graders::HtmlAttribute.new(description, :id) },
+        ->(description) { ::LinkThumbnailer::Graders::Position.new(description, weigth: 3) },
+        ->(description) { ::LinkThumbnailer::Graders::LinkDensity.new(description) },
+      ]
+      @description_min_length = 50
+      @positive_regex = /article|body|content|entry|hentry|main|page|pagination|post|text|blog|story/i
+      @negative_regex = /combx|comment|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget|modal/i
+      @image_limit    = 5
+      @image_stats    = true
+      @raise_on_invalid_format = false
+      @max_concurrency = 20
+      @scrapers = [:opengraph, :default]
+      @http_override_headers = { 'Accept-Encoding' => 'none' }
+      @encoding = 'utf-8'
+    end
+
+	end
+end

lib/link_thumbnailer/exceptions.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   Exceptions         = Class.new(StandardError)
   RedirectLimit      = Class.new(Exceptions)

lib/link_thumbnailer/grader.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'delegate'
 require 'link_thumbnailer/graders/base'
 require 'link_thumbnailer/graders/length'

lib/link_thumbnailer/graders/base.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'delegate'
 
 module LinkThumbnailer

lib/link_thumbnailer/graders/html_attribute.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module Graders
     class HtmlAttribute < ::LinkThumbnailer::Graders::Base

lib/link_thumbnailer/graders/length.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module Graders
     class Length < ::LinkThumbnailer::Graders::Base

lib/link_thumbnailer/graders/link_density.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module Graders
     class LinkDensity < ::LinkThumbnailer::Graders::Base

lib/link_thumbnailer/graders/position.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module Graders
     class Position < ::LinkThumbnailer::Graders::Base

lib/link_thumbnailer/image_comparator.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'link_thumbnailer/image_comparators/base'
 require 'link_thumbnailer/image_comparators/size'
 

lib/link_thumbnailer/image_comparators/base.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module ImageComparators
     class Base

lib/link_thumbnailer/image_comparators/size.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LinkThumbnailer
   module ImageComparators
     class Size < ::LinkThumbnailer::ImageComparators::Base

lib/link_thumbnailer/image_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'image_info'
 
 module LinkThumbnailer

lib/link_thumbnailer/image_validator.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'delegate'
 
 module LinkThumbnailer

lib/link_thumbnailer/model.rb

@@ -1,17 +1,19 @@
-module LinkThumbnailer
-  class Model
-
-    def to_json(*args)
-      as_json.to_json(*args)
-    end
-
-    private
-
-    def sanitize(str)
-      return unless str
-
-      str.encode!("UTF-16", "UTF-8", invalid: :replace, undef: :replace, replace: "")
-      str.encode!("UTF-8", "UTF-16").strip.gsub(/[\r\n\f]+/, "\n")
-    end
-  end
-end
+# frozen_string_literal: true
+module LinkThumbnailer
+  class Model
+
+    def to_json(*args)
+      as_json.to_json(*args)
+    end
+
+    private
+
+    def sanitize(str)
+      return unless str
+
+      str = str.dup
+      str.encode!("UTF-16", "UTF-8", invalid: :replace, undef: :replace, replace: "")
+      str.encode!("UTF-8", "UTF-16").strip.gsub(/[\r\n\f]+/, "\n")
+    end
+  end
+end

lib/link_thumbnailer/models/description.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'link_thumbnailer/model'
 require 'link_thumbnailer/grader'
 

lib/link_thumbnailer/models/favicon.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'link_thumbnailer/model'
 
 module LinkThumbnailer

lib/link_thumbnailer/models/image.rb

@@ -1,54 +1,55 @@
-require 'link_thumbnailer/model'
-require 'link_thumbnailer/image_parser'
-require 'link_thumbnailer/image_comparator'
-require 'link_thumbnailer/image_validator'
-
-module LinkThumbnailer
-  module Models
-    class Image < ::LinkThumbnailer::Model
-
-      attr_reader :src, :type, :size
-
-      def initialize(src, size = nil, type = nil)
-        @src  = src
-        @size = size || parser.size
-        @type = type || parser.type
-      end
-
-      def to_s
-        src.to_s
-      end
-
-      def <=>(other)
-        comparator.call(other)
-      end
-
-      def valid?
-        validator.call
-      end
-
-      def as_json(*)
-        {
-          src:  src.to_s,
-          size: size,
-          type: type
-        }
-      end
-
-      private
-
-      def parser
-        @parser ||= ::LinkThumbnailer::ImageParser.new(src)
-      end
-
-      def validator
-        ::LinkThumbnailer::ImageValidator.new(self)
-      end
-
-      def comparator
-        ::LinkThumbnailer::ImageComparator.new(self)
-      end
-
-    end
-  end
-end
+# frozen_string_literal: true
+require 'link_thumbnailer/model'
+require 'link_thumbnailer/image_parser'
+require 'link_thumbnailer/image_comparator'
+require 'link_thumbnailer/image_validator'
+
+module LinkThumbnailer
+  module Models
+    class Image < ::LinkThumbnailer::Model
+
+      attr_reader :src, :type, :size
+
+      def initialize(src, size = nil, type = nil)
+        @src  = src
+        @size = size || parser.size
+        @type = type || parser.type
+      end
+
+      def to_s
+        src.to_s
+      end
+
+      def <=>(other)
+        comparator.call(other)
+      end
+
+      def valid?
+        validator.call
+      end
+
+      def as_json(*)
+        {
+          src:  src.to_s,
+          size: size,
+          type: type
+        }
+      end
+
+      private
+
+      def parser
+        @parser ||= ::LinkThumbnailer::ImageParser.new(src)
+      end
+
+      def validator
+        ::LinkThumbnailer::ImageValidator.new(self)
+      end
+
+      def comparator
+        ::LinkThumbnailer::ImageComparator.new(self)
+      end
+
+    end
+  end
+end

lib/link_thumbnailer/models/title.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'link_thumbnailer/model'
 
 module LinkThumbnailer

lib/link_thumbnailer/models/video.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'link_thumbnailer/model'
 require 'link_thumbnailer/video_parser'