feat: add anonymize address middleware

main.go

@@ -8,10 +8,11 @@ import (
 	"net/http"
 	"os"
 
-	"github.com/go-sql-driver/mysql"
-
 	"github.com/gin-contrib/cors"
 	"github.com/gin-gonic/gin"
+	"github.com/go-sql-driver/mysql"
+
+	"log101-blog-services/middleware"
 )
 
 var db *sql.DB
@@ -101,7 +102,10 @@ func main() {
 	}
 
 	corsConfig.AllowHeaders = []string{"hx-current-url", "hx-request"}
+
+	// Middlewares
 	r.Use(cors.New(corsConfig))
+	r.Use(middleware.AnonymizeIPMiddleware())
 
 	var hxPostUrl string
 	if ginMode == gin.DebugMode {
@@ -145,7 +149,7 @@ func main() {
 			}
 
 			// Add the new emoji entry to the database
-			_, err := db.Exec("INSERT INTO emoji_clicks (post_id, emoji) VALUES (?, ?)", postId, emoji)
+			_, err := db.Exec("INSERT INTO emoji_clicks (user_anon_data, post_id, emoji) VALUES (?, ?, ?) ON DUPLICATE KEY UPDATE emoji = ?", c.Request.RemoteAddr, postId, emoji, emoji)
 			if err != nil {
 				c.HTML(http.StatusOK, "emoji_form.tmpl", gin.H{"error": "error writing to database", "postId": postId, "hxPostUrl": hxPostUrl})
 				return

middleware/middleware.go

@@ -0,0 +1,48 @@
+package middleware
+
+import (
+	"net/netip"
+
+	"github.com/gin-gonic/gin"
+)
+
+// AnonymizeIPMiddleware masks the last segment of IPv4 addresses
+// and the last 80 bits of IPv6 addresses.
+func AnonymizeIPMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		ip := c.ClientIP()
+		anonymizedIP := anonymizeIP(ip)
+		c.Request.RemoteAddr = anonymizedIP
+		c.Next()
+	}
+}
+
+// anonymizeIP masks the last segment of IPv4 addresses
+// and the last 80 bits of IPv6 addresses.
+func anonymizeIP(ip string) string {
+	parsedIP, err := netip.ParseAddr(ip)
+	if err != nil {
+		// If there's an error parsing the IP, return the original IP
+		return ip
+	}
+
+	if parsedIP.Is4() {
+		// Mask the last octet for IPv4
+		ipPrefix, err := parsedIP.Prefix(24)
+		if err != nil {
+			return ip
+		}
+
+		return ipPrefix.Masked().String()
+	} else if parsedIP.Is6() {
+		// Mask the last 80 bits for IPv6
+		ipPrefix, err := parsedIP.Prefix(48)
+		if err != nil {
+			return ip
+		}
+		return ipPrefix.Masked().String()
+	}
+
+	// If it's neither IPv4 nor IPv6, return the original IP
+	return ip
+}

schema.sql

@@ -5,6 +5,7 @@ USE emojis;
 
 CREATE TABLE IF NOT EXISTS emoji_clicks (
     id INT PRIMARY KEY AUTO_INCREMENT,
+    user_anon_data TEXT NOT NULL,
     post_id TEXT NOT NULL,
     emoji TEXT NOT NULL,
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP