Merge pull request #97 from dysania/caching-support-for-preview

Caching support for preview

lib/onebox.rb

@@ -4,14 +4,30 @@
 require "mustache"
 require "opengraph_parser"
 require "verbal_expressions"
+require "ostruct"
+require "moneta"
 
 require_relative "onebox/version"
 require_relative "onebox/preview"
 require_relative "onebox/matcher"
 require_relative "onebox/engine"
 
 module Onebox
-  def self.preview(url, args={})
-    Preview.new(url, args)
+  DEFAULTS = {
+    cache: Moneta.new(:Memory, expires: true, serializer: :json)
+  }
+
+  @@defaults = DEFAULTS
+
+  def self.preview(url, options = Onebox.defaults)
+    Preview.new(url, options)
+  end
+
+  def self.defaults
+    @@defaults
+  end
+
+  def self.defaults=(options)
+    @@defaults = DEFAULTS.merge(options)
   end
 end

lib/onebox/engine.rb

@@ -10,30 +10,48 @@ def self.engines
       end.map(&method(:const_get))
     end
 
-    def initialize(link)
+    attr_reader :cache
+
+    def initialize(link, cache = Onebox.defaults)
       @url = link
-      @body = read
-      @data = extracted_data
+      @cache = cache
     end
 
     def to_html
-      Mustache.render(template, @data)
+      Mustache.render(template, record)
     end
 
     private
 
-    def read
-      Nokogiri::HTML(open(@url))
+    def record
+      if cache.key?(@url)
+        cache.fetch(@url)
+      else
+        cache.store(@url, data)
+      end
+    end
+
+    # raises error if not defined in onebox engine
+    # in each onebox, uses either Nokogiri or OpenGraph to get raw HTML from url
+    def raw
+      raise NoMethodError, "Engines need to implement this method"
     end
 
     def template
       File.read(File.join("templates", "#{template_name}.handlebars"))
     end
 
+    # calculates handlebars template name for onebox using name of engine
     def template_name
       self.class.name.split("::").last.downcase.gsub(/onebox/, "")
     end
 
+    # raises error if not defined in onebox engine
+    # in each onebox, returns hash of desired onebox content
+    def data
+      raise NoMethodError, "Engines need this method defined"
+    end
+
     module ClassMethods
       def ===(object)
         if object.kind_of?(String)
@@ -51,6 +69,7 @@ def matches(&block)
 end
 
 require_relative "engine/open_graph"
+require_relative "engine/html"
 require_relative "engine/example_onebox"
 require_relative "engine/amazon_onebox"
 require_relative "engine/bliptv_onebox"

lib/onebox/engine/amazon_onebox.rb

@@ -2,6 +2,7 @@ module Onebox
   module Engine
     class AmazonOnebox
       include Engine
+      include HTML
 
       matches do
         #/^https?:\/\/(?:www\.)?amazon.(com|ca)\/.*$/
@@ -10,13 +11,13 @@ class AmazonOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          name: @body.css("html body h1").inner_text,
-          image: @body.css("html body #main-image").first["src"],
-          description: @body.css("html body #postBodyPS").inner_text,
-          price: @body.css("html body .priceLarge").inner_text
+          name: raw.css("h1").inner_text,
+          image: raw.css("#main-image").first["src"],
+          description: raw.css("#postBodyPS").inner_text,
+          price: raw.css(".priceLarge").inner_text
         }
       end
     end

lib/onebox/engine/bliptv_onebox.rb

@@ -11,13 +11,13 @@ class BliptvOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images[0],
-          description: @body.description,
-          video: @body.metadata[:video].first[:_value]
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video].first[:_value]
         }
       end
     end

lib/onebox/engine/clikthrough_onebox.rb

@@ -11,11 +11,11 @@ class ClikThroughOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          description: @body.description
+          title: raw.title,
+          description: raw.description
         }
       end
     end

lib/onebox/engine/college_humor_onebox.rb

@@ -11,13 +11,13 @@ class CollegeHumorOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images[0],
-          description: @body.description,
-          video: @body.metadata[:video].first[:_value]
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video].first[:_value]
         }
       end
     end

lib/onebox/engine/dailymotion_onebox.rb

@@ -11,13 +11,13 @@ class DailymotionOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images.first,
-          description: @body.description,
-          video: @body.metadata[:video][1][:_value]
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video][1][:_value]
         }
       end
     end

lib/onebox/engine/dotsub_onebox.rb

@@ -11,13 +11,13 @@ class DotsubOnebox
 
       private
 
-      def extracted_data
+      def data
         {
-          url: @body.metadata[:url].first[:_value],
-          title: @body.title,
-          image: @body.images.first,
-          description: @body.description,
-          video: @body.metadata[:video].first[:_value]
+          url: @url,
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video].first[:_value]
         }
       end
     end

lib/onebox/engine/example_onebox.rb

@@ -2,21 +2,22 @@ module Onebox
   module Engine
     class ExampleOnebox
       include Engine
+      include HTML
 
       matches do
         find "example.com"
       end
 
       private
 
-      def extracted_data
+      def data
         {
-          header: @body.css("html body h1")
+          header: raw.css("h1").inner_text
         }
       end
 
       def template
-        %|<div class="onebox">{{{header}}}</div>|
+        %|<div class="onebox">{{header}}</div>|
       end
     end
   end

lib/onebox/engine/flickr_onebox.rb

@@ -11,12 +11,12 @@ class FlickrOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images[0],
-          description: @body.description
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description
         }
       end
     end

lib/onebox/engine/funny_or_die_onebox.rb

@@ -11,13 +11,13 @@ class FunnyOrDieOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images.first,
-          description: @body.description,
-          video: @body.metadata[:video].first[:url].first[:_value]
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video].first[:url].first[:_value]
         }
       end
     end

lib/onebox/engine/html.rb

@@ -0,0 +1,11 @@
+module Onebox
+  module Engine
+    module HTML
+      private
+
+      def raw
+        @raw ||= Nokogiri::HTML(open(@url))
+      end
+    end
+  end
+end

lib/onebox/engine/hulu_onebox.rb

@@ -11,13 +11,13 @@ class HuluOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images[0],
-          description: @body.description,
-          video: @body.metadata[:video][1][:_value]
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video][1][:_value]
         }
       end
     end

lib/onebox/engine/nfb_onebox.rb

@@ -11,12 +11,12 @@ class NFBOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          description: @body.description,
-          video: @body.metadata[:video].first[:_value]
+          title: raw.title,
+          description: raw.description,
+          video: raw.metadata[:video].first[:_value]
         }
       end
     end

lib/onebox/engine/open_graph.rb

@@ -1,8 +1,10 @@
 module Onebox
   module Engine
     module OpenGraph
-      def read
-        ::OpenGraph.new(@url)
+      private
+
+      def raw
+        @raw ||= ::OpenGraph.new(@url)
       end
     end
   end

lib/onebox/engine/qik_onebox.rb

@@ -2,6 +2,7 @@ module Onebox
   module Engine
     class QikOnebox
       include Engine
+      include HTML
 
       matches do
         # /^https?\:\/\/qik\.com\/video\/.*$/
@@ -10,11 +11,11 @@ class QikOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.css(".info h2").inner_text,
-          image: @body.css(".userphoto").first["src"]
+          title: raw.css(".info h2").inner_text,
+          image: raw.css(".userphoto").first["src"]
         }
       end
     end

lib/onebox/engine/revision3_onebox.rb

@@ -11,13 +11,13 @@ class Revision3Onebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images.first,
-          description: @body.description,
-          video: @body.metadata[:video].first[:_value]
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description,
+          video: raw.metadata[:video].first[:_value]
         }
       end
     end

lib/onebox/engine/slideshare_onebox.rb

@@ -11,12 +11,12 @@ class SlideshareOnebox
 
       private
 
-      def extracted_data
+      def data
         {
           url: @url,
-          title: @body.title,
-          image: @body.images.first,
-          description: @body.description
+          title: raw.title,
+          image: raw.images.first,
+          description: raw.description
         }
       end
     end