[#11] Add open graph tags

Initial pass at open graph tags for sharing content on social media. Only
catering for minimal set of tags and use cases for now.

config.toml

@@ -4,6 +4,9 @@ defaultContentLanguage = 'en'
 title = 'Yvant'
 theme = 'yvant'
 
+[params]
+  logo = 'yvant.png'
+
 [languages]
   [languages.en]
     languageCode = 'en'

themes/yvant/layouts/partials/head.html

@@ -2,9 +2,42 @@
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width, initial-scale=1"/>
   <meta http-equiv="Permissions-Policy" content="interest-cohort=()">
-  <meta name="description" content="{{ default (truncate 160 .Summary) .Description }}"/>
+
   {{ $title := print .Title " | " .Site.Title }}
-  {{ if .IsHome }}{{ $title = print .Site.Title " | " .Title }}{{ end }}
+  {{ $description := default (truncate 160 .Summary) .Params.description }}
+  {{ $image := print .Site.BaseURL .Site.Params.logo }}
+  {{ if .IsHome }}
+  {{ $title = print .Site.Title " | " .Title }}
+  {{ end }}
+  {{ if .Params.image }}
+  {{ $image = print .Permalink .Params.image }}
+  {{ end }}
+
+  <!-- Start of Open Graph -->
+  <meta property="og:title" content="{{ $title }}">
+  <meta property="og:description" content="{{ $description }}">
+  <meta property="og:url" content="{{ .Permalink }}">
+  <meta property="og:site_name" content="{{ .Site.Title }}">
+  {{ if .IsPage }}
+  <meta property="og:type" content="article">
+  {{ else }}
+  <meta property="og:type" content="website">
+  {{ end }}
+  <meta property="og:image" content="{{ $image }}">
+  {{ range .Params.tags }}
+  <meta property="og:tags" content="{{ . }}">
+  {{ end }}
+  <!-- End of Open Graph -->
+  <!-- Start of Twitter -->
+  <meta property="twitter:card" content="summary">
+  <meta property="twitter:description" content="{{ $description }}">
+  <meta property="twitter:title" content="{{ $title }}">
+  {{ if .Params.image }}
+  <meta property="twitter:image" content="{{ $image }}">
+  {{ end }}
+  <!-- End of Twitter -->
+
+  <meta name="description" content="{{ $description }}"/>
   <title>{{ $title }}</title>
   <link rel="icon" href="/Y.ico"/>
   <link rel="stylesheet" href="/css/pico.min.css"/>