Add link previews

web/templates/layout.html

@@ -4,6 +4,19 @@
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <title>{{.Title}} - Uncensored Send</title>
+{{- with .Preview}}
+<meta property="og:type" content="website">
+<meta property="og:title" content="{{$.Title}} - Uncensored Send">
+<meta property="og:description" content="{{.Description}}">
+{{- if .URL}}
+<meta property="og:url" content="{{.URL}}">
+{{- end}}
+{{- if .Author}}
+<meta name="author" content="{{.Author}}">
+{{- end}}
+<meta name="description" content="{{.Description}}">
+<meta name="twitter:card" content="summary">
+{{- end}}
 <link rel="stylesheet" href="{{.Base}}static/style.css">
 {{if .Favicon}}<link rel="icon" href="{{.Favicon}}">{{end}}
 </head>
@@ -11,8 +24,6 @@
 <header>
   <a class="brand" href="{{.Base}}">Uncensored&nbsp;Send</a>
   <nav>
-    {{- /* Uploading is what the site is for, so it is a named destination and
-         not only a click on the wordmark. */}}
     <a href="{{.Base}}">Upload</a>
     {{if .User}}
       <a href="{{.Base}}files">{{if .Admin}}Administration{{else}}My files{{end}}</a>