add meta description

blog/view/detail.ls

@@ -3,6 +3,7 @@
     local data = arg[1]
     local order = arg[2]
     local content = nil;
+    local url = nil
     local topview = loadscript(BLOG_ROOT.."/view/top.ls")
     local class = "card"
     if HEADER.mobile then
@@ -31,9 +32,9 @@
                 title = content:sub(b+1, c-1)
             end
         end
-        topview(title, true)
+        url = "https://blog.lxsang.me/r:id:"..data.id
+        topview(title, true, url, data.tags)
     end
-    local url = "https://blog.lxsang.me/r:id:"..data.id
     -- fetch the similar posts from database
     local db = require("db.model").get(BLOG_ADMIN,"st_similarity", nil)
     local similar_posts = nil

blog/view/top.ls

@@ -2,6 +2,8 @@
     local arg = {...}
     local title = arg[1]
     local render = arg[2]
+    local url = arg[3]
+    local tags = arg[4]
     local cls = ""
     if HEADER.mobile then
         cls = "navmobile"
@@ -27,6 +29,10 @@
         <script src="rst/gscripts/jquery-3.2.1.min.js"> </script>
         <script src="rst/main.js"></script>
 <?lua if render then ?>
+        <meta property="og:url"                content="<?=url?>" />
+        <meta property="og:type"               content="article" />
+        <meta property="og:title"              content="<?=title?>" />
+        <meta property="og:description"        content="<?=tags?>" />
         <link rel="stylesheet" type="text/css" href="rst/hljs/github.css" />
         <link rel="stylesheet" type="text/css" href="rst/katex/katex.min.css" />
         <script src="rst/hljs/highlight.pack.js"> </script>