lib/jekyll-linkpreview.rb in jekyll-linkpreview-0.1.0 vs lib/jekyll-linkpreview.rb in jekyll-linkpreview-0.2.0

@@ -4,35 +4,86 @@
 require "metainspector"
 require "jekyll-linkpreview/version"
 
 module Jekyll
   module Linkpreview
+    class OpenGraphProperties
+      def get(url)
+        og_properties = fetch(url)
+        og_url = get_og_property(og_properties, 'og:url')
+        domain = extract_domain(og_url)
+        image_url = get_og_property(og_properties, 'og:image')
+        {
+          'title'       => get_og_property(og_properties, 'og:title'),
+          'url'         => og_url,
+          'image'       => convert_to_absolute_url(image_url, domain),
+          'description' => get_og_property(og_properties, 'og:description'),
+          'domain'      => domain
+        }
+      end
+
+      private
+      def get_og_property(properties, key)
+        if !properties.key? key then
+          return nil
+        end
+        properties[key][0]
+      end
+
+      private
+      def fetch(url)
+        MetaInspector.new(url).meta_tags['property']
+      end
+
+      private
+      def convert_to_absolute_url(url, domain)
+        if url.nil? then
+          return nil
+        end
+        # root relative url
+        if url[0] == '/' then
+          return "//#{domain}#{url}"
+        end
+        url
+      end
+
+      private
+      def extract_domain(url)
+        if url.nil? then
+          return nil
+        end
+        url.match(%r{(http|https)://([^/]+).*})[-1]
+      end
+    end
+
     class LinkpreviewTag < Liquid::Tag
+      @@cache_dir = '_cache'
+
       def initialize(tag_name, markup, parse_context)
         super
         @markup = markup.rstrip()
-        @cache_filepath = "_cache/%s.json" % Digest::MD5.hexdigest(@markup)
+        @og_properties = OpenGraphProperties.new
       end
 
       def render(context)
-        properties = get_properties()
+        url = get_url_from(context)
+        properties = get_properties(url)
         title       = properties['title']
-        url         = properties['url']
         image       = properties['image']
         description = properties['description']
         domain      = properties['domain']
-        if title.nil? || url.nil? || image.nil? then
+        if title.nil? || image.nil? || description.nil? || domain.nil? then
           html = <<-EOS
 <div class="jekyll-linkpreview-wrapper">
-  <p><a href="#{@markup}" target="_blank">#{@markup}</a></p>
+  <p><a href="#{url}" target="_blank">#{url}</a></p>
 </div>
           EOS
           return html
         end
         html = <<-EOS
 <div class="jekyll-linkpreview-wrapper">
-  <p><a href="#{@markup}" target="_blank">#{@markup}</a></p>
+  <p><a href="#{url}" target="_blank">#{url}</a></p>
   <div class="jekyll-linkpreview-wrapper-inner">
     <div class="jekyll-linkpreview-content">
       <div class="jekyll-linkpreview-image">
         <a href="#{url}" target="_blank">
           <img src="#{image}" />
@@ -44,64 +95,45 @@
         </h2>
         <div class="jekyll-linkpreview-description">#{description}</div>
       </div>
     </div>
     <div class="jekyll-linkpreview-footer">
-      <a href="#{url}" target="_blank">#{domain}</a>
+      <a href="//#{domain}" target="_blank">#{domain}</a>
     </div>
   </div>
 </div>
         EOS
         html
       end
 
-      def get_properties()
-        if File.exist?(@cache_filepath) then
-          return load_cache_file
+      def get_properties(url)
+        cache_filepath = "#{@@cache_dir}/%s.json" % Digest::MD5.hexdigest(url)
+        if File.exist?(cache_filepath) then
+          return load_cache_file(cache_filepath)
+        end
+        properties = @og_properties.get(url)
+        if Dir.exists?(@@cache_dir) then
+          save_cache_file(cache_filepath, properties)
         else
-          og_properties = fetch_og_properties()
-          url = get_og_property(og_properties, 'og:url')
-          properties = {
-            'title'       => get_og_property(og_properties, 'og:title'),
-            'url'         => url,
-            'image'       => get_og_property(og_properties, 'og:image'),
-            'description' => get_og_property(og_properties, 'og:description'),
-            'domain'      => extract_domain(url)
-          }
-          save_cache_file(properties)
-          return properties
+          # TODO: This message will be shown at all linkprevew tag
+          warn "'#{@@cache_dir}' directory does not exist. Create it for caching."
         end
+        properties
       end
 
       private
-      def fetch_og_properties()
-        MetaInspector.new(@markup).meta_tags['property']
+      def get_url_from(context)
+        context.scopes[0].key?(@markup) ? context.scopes[0][@markup] : @markup
       end
 
       private
-      def get_og_property(properties, key)
-        if !properties.key? key then
-          return nil
-        end
-        properties[key][0]
+      def load_cache_file(filepath)
+        JSON.parse(File.open(filepath).read)
       end
 
-      private
-      def extract_domain(url)
-        if url.nil? then
-          return nil
-        end
-        url.match(%r{(http|https)://([^/]+).*})[-1]
-      end
-
-      private
-      def load_cache_file()
-        JSON.parse(File.open(@cache_filepath).read)
-      end
-
-      private
-      def save_cache_file(properties)
-        File.open(@cache_filepath, 'w').write(JSON.generate(properties))
+      protected
+      def save_cache_file(filepath, properties)
+        File.open(filepath, 'w').write(JSON.generate(properties))
       end
     end
   end
 end