Add og metadata

Author: st0012

lib/rdoc/generator/template/aliki/_head.rhtml

@@ -30,6 +30,48 @@
 <link rel="canonical" href="<%= canonical_url %>">
 <%- end -%>
 
+<!-- Open Graph / Facebook -->
+<meta property="og:type" content="website">
+<meta property="og:title" content="<%= h @title %>">
+<%- if defined?(klass) -%>
+  <%- if klass.comment.empty? -%>
+    <meta property="og:description" content="Documentation for <%= h klass.full_name %> <%= h klass.type %> - API reference and code examples">
+  <%- else -%>
+    <meta property="og:description" content="<%= h excerpt(klass.comment) %>">
+  <%- end -%>
+<%- elsif defined?(file) -%>
+  <%- if file.comment.empty? -%>
+    <meta property="og:description" content="<%= h file.page_name %> - <%= h @title %> documentation">
+  <%- else -%>
+    <meta property="og:description" content="<%= h excerpt(file.comment) %>">
+  <%- end -%>
+<%- else -%>
+  <meta property="og:description" content="API documentation for <%= h @title %> - Browse classes, modules, and methods">
+<%- end -%>
+<%- if canonical_url = @options.canonical_root -%>
+<% canonical_url = current.canonical_url if defined?(current) %>
+<meta property="og:url" content="<%= canonical_url %>">
+<%- end -%>
+
+<!-- Twitter -->
+<meta name="twitter:card" content="summary">
+<meta name="twitter:title" content="<%= h @title %>">
+<%- if defined?(klass) -%>
+  <%- if klass.comment.empty? -%>
+    <meta name="twitter:description" content="Documentation for <%= h klass.full_name %> <%= h klass.type %> - API reference and code examples">
+  <%- else -%>
+    <meta name="twitter:description" content="<%= h excerpt(klass.comment) %>">
+  <%- end -%>
+<%- elsif defined?(file) -%>
+  <%- if file.comment.empty? -%>
+    <meta name="twitter:description" content="<%= h file.page_name %> - <%= h @title %> documentation">
+  <%- else -%>
+    <meta name="twitter:description" content="<%= h excerpt(file.comment) %>">
+  <%- end -%>
+<%- else -%>
+  <meta name="twitter:description" content="API documentation for <%= h @title %> - Browse classes, modules, and methods">
+<%- end -%>
+
 <script type="text/javascript">
   var rdoc_rel_prefix = "<%= h asset_rel_prefix %>/";
   var index_rel_prefix = "<%= h rel_prefix %>/";