From 37a628ad09b1aaa25b5de611566bd2e5fc801c20 Mon Sep 17 00:00:00 2001
From: partisan <none@noone.no>
Date: Thu, 29 Aug 2024 22:48:04 +0200
Subject: [PATCH] added lazy loading to img for blogs

---
 main.go | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/main.go b/main.go
index 6fe28d0..cb3350c 100644
--- a/main.go
+++ b/main.go
@@ -216,6 +216,41 @@ func renderIndex(w http.ResponseWriter) {
 	renderTemplate(w, "index.html", nil)
 }
 
+// Helper function to add loading="lazy" to all img tags
+func injectLazyLoading(htmlContent string) string {
+	// Split the content by <img tags to process them individually
+	parts := strings.Split(htmlContent, "<img")
+
+	// Start with the first part which is before any <img tag
+	modifiedContent := parts[0]
+
+	// Iterate over the remaining parts
+	for _, part := range parts[1:] {
+		// Find the closing bracket of the img tag
+		endOfTag := strings.Index(part, ">")
+		if endOfTag == -1 {
+			// If no closing bracket is found, add the remaining part as is
+			modifiedContent += "<img" + part
+			continue
+		}
+
+		// Extract the actual <img tag
+		imgTag := part[:endOfTag]
+
+		// Check if loading="lazy" is already present
+		if !strings.Contains(imgTag, "loading=") {
+			// Insert loading="lazy" before the closing of the img tag
+			imgTag = " loading=\"lazy\"" + imgTag
+		}
+
+		// Rebuild the full content with the modified img tag
+		modifiedContent += "<img" + imgTag + part[endOfTag:]
+	}
+
+	return modifiedContent
+}
+
+// For redering HTML Blogs
 func renderBlogEntry(w http.ResponseWriter, r *http.Request, blogName string, entryNumber int) {
 	var blog Blog
 	for _, b := range blogs {
@@ -249,16 +284,21 @@ func renderBlogEntry(w http.ResponseWriter, r *http.Request, blogName string, en
 		}
 	}
 
+	// Convert .md to HTML
 	htmlContent := blackfriday.Run([]byte(entry.Content))
 
+	// Double check "/news-assets/" in URL of images
 	htmlContent = bytes.ReplaceAll(htmlContent, []byte("src=\"./"), []byte(fmt.Sprintf("src=\"/news-assets/%d/", entryNumber)))
 
+	// Apply lazy loading to the generated HTML content
+	htmlContentWithLazyLoading := injectLazyLoading(string(htmlContent))
+
 	pageData := PageData{
 		Title:    entry.Title,
 		Date:     entry.Date.Format("2006-01-02 15:04"),
 		Desc:     entry.Description,
 		Author:   entry.Author,
-		Content:  template.HTML(htmlContent),
+		Content:  template.HTML(htmlContentWithLazyLoading),
 		PrevLink: prevLink,
 		NextLink: nextLink,
 	}