Add meta tags for twitter and facebook

helpers/middleman_casper_helpers.rb

@@ -117,4 +117,24 @@ module MiddlemanCasperHelpers
   def author_path
     "#{blog.options.prefix.to_s}/author/#{blog_author.name.parameterize}/"
   end
+
+  def og_type
+    if is_blog_article?
+      'article'
+    else
+      'website'
+    end
+  end
+
+  def og_title
+    if current_page.data.title
+      current_page.data.title
+    elsif is_tag_page?
+      current_resource.metadata[:locals]['tagname']
+    elsif is_blog_article?
+      current_article.title
+    else
+      nil
+    end
+  end
 end

source/layouts/layout.haml

@@ -7,6 +7,28 @@
     %meta{name: :viewport, content: 'width=device-width, initial-scale=1.0'}
     %meta{'http-equiv' => 'X-UA-Compatible', content: 'IE=edge'}
     %meta{name: 'HandheldFriendly', content: 'True'}
+
+    %meta{property: "og:site_name", content: blog_settings.name}
+    %meta{property: "og:type", content: og_type}
+    - if !og_title.nil?
+      %meta{property: "og:title", content: og_title}
+    %meta{property: "og:description", content: page_description}
+    %meta{property: "og:url", content: URI.join(blog_settings.url, current_page.url)}
+    - if cover?
+      %meta{property: "og:image", content: URI.join(blog_settings.url, image_path(current_page.data.cover))}
+    - if is_blog_article?
+      %meta{property: "article:published_time", content: current_article.date.strftime('%Y-%m-%d')}
+
+    %meta{name: "twitter:card", content: "summary"}
+    - if blog_author.twitter
+      %meta{name: "twitter:site", content: "@#{blog_author.twitter}"}
+    - if og_title
+      %meta{name: "twitter:title", content: og_title}
+    %meta{name: "twitter:description", content: page_description}
+    %meta{name: "twitter:url", content: URI.join(blog_settings.url, current_page.url)}
+    - if cover?
+      %meta{name: "twitter:image:src", content: URI.join(blog_settings.url, image_path(current_page.data.cover))}
+
     = feed_tag :atom, "#{blog.options.prefix.to_s}/feed.xml", title: "Atom Feed"
     = favicon_tag 'images/favicon.ico'
     = stylesheet_link_tag :application