Harden RSS feed for Naver

src/TaxBaik.Web/Pages/Rss.cshtml

@@ -3,7 +3,6 @@
 @{
     Layout = null;
     Response.ContentType = "application/rss+xml; charset=utf-8";
-}@{
     var rssContent = new System.Text.StringBuilder();
     rssContent.AppendLine("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
     rssContent.AppendLine("<rss version=\"2.0\" xmlns:atom=\"http://www.w3.org/2005/Atom\" xmlns:content=\"http://purl.org/rss/1.0/modules/content/\">");
@@ -11,27 +10,39 @@
     rssContent.AppendLine("    <title>백원숙 세무회계 - 블로그</title>");
     rssContent.AppendLine("    <link>https://www.taxbaik.com</link>");
     rssContent.AppendLine("    <description>세무사 백원숙의 세금, 부동산, 가족자산 전문 블로그</description>");
-    rssContent.AppendLine("    <language>ko-kr</language>");
+    rssContent.AppendLine("    <language>ko-KR</language>");
     rssContent.AppendLine($"    <lastBuildDate>{Model.LastBuildDate}</lastBuildDate>");
     rssContent.AppendLine("    <atom:link href=\"https://www.taxbaik.com/rss.xml\" rel=\"self\" type=\"application/rss+xml\" />");
     rssContent.AppendLine("    <ttl>60</ttl>");
 
     foreach (var post in Model.Posts)
     {
+        var postUrl = $"https://www.taxbaik.com/blog/{Uri.EscapeDataString(post.Slug)}";
+        var description = post.Content?.Substring(0, Math.Min(200, post.Content?.Length ?? 0)) ?? string.Empty;
+        var safeDescription = description.Replace("]]>", "]]]]><![CDATA[>");
+        var safeContent = post.Content?.Replace("]]>", "]]]]><![CDATA[>");
+
         rssContent.AppendLine("    <item>");
         rssContent.AppendLine($"      <title>{System.Net.WebUtility.HtmlEncode(post.Title)}</title>");
-        rssContent.AppendLine($"      <link>https://www.taxbaik.com/blog/{post.Slug}</link>");
-        rssContent.AppendLine($"      <guid isPermaLink=\"true\">https://www.taxbaik.com/blog/{post.Slug}</guid>");
-        rssContent.AppendLine($"      <pubDate>{post.PublishedAt?.ToString("R")}</pubDate>");
-        var desc = post.Content?.Substring(0, Math.Min(200, post.Content?.Length ?? 0)) ?? "";
-        rssContent.AppendLine($"      <description>{System.Net.WebUtility.HtmlEncode(desc)}</description>");
-        if (!string.IsNullOrEmpty(post.Content))
+        rssContent.AppendLine($"      <link>{postUrl}</link>");
+        rssContent.AppendLine($"      <guid isPermaLink=\"true\">{postUrl}</guid>");
+
+        if (post.PublishedAt is not null)
         {
-            rssContent.AppendLine($"      <content:encoded><![CDATA[{post.Content.Replace("]]>", "]]]]><![CDATA[>")}]]></content:encoded>");
+            rssContent.AppendLine($"      <pubDate>{post.PublishedAt.Value.ToUniversalTime():R}</pubDate>");
         }
+
+        rssContent.AppendLine($"      <description><![CDATA[{safeDescription}]]></description>");
+
+        if (!string.IsNullOrWhiteSpace(safeContent))
+        {
+            rssContent.AppendLine($"      <content:encoded><![CDATA[{safeContent}]]></content:encoded>");
+        }
+
         rssContent.AppendLine("    </item>");
     }
 
     rssContent.AppendLine("  </channel>");
     rssContent.AppendLine("</rss>");
-}@Html.Raw(rssContent.ToString())
+}
+@Html.Raw(rssContent.ToString())