implement canonical URL handling with server and client-side support, add middleware for pathname access, and create hooks for dynamic canonical URL injection

lib/getCanonicalUrl.js

@@ -0,0 +1,80 @@
+import { headers } from "next/headers";
+import citiesData from "@/data/city.json";
+
+const MAIN_DOMAIN = "https://nobat724.com";
+
+/**
+ * Determines if the current domain should have a canonical tag
+ * and returns the canonical URL if needed
+ */
+export function getCanonicalUrl() {
+    try {
+        const headersList = headers();
+        const host = headersList.get("host") || "";
+        const pathname = headersList.get("x-pathname") || "/";
+
+        // Normalize host (remove www and convert to lowercase)
+        const normalizedHost = host.toLowerCase().replace(/^www\./, "");
+
+        // Check if current domain is the main domain
+        if (normalizedHost === "nobat724.com") {
+            return null; // No canonical needed for main domain
+        }
+
+        // Check if this is a subdomain/different domain from our city data
+        const subdomain = normalizedHost.split(".")[0];
+        const matchedCity = citiesData.find((city) => {
+            const cityDomain = city.domain.toLowerCase();
+            return cityDomain.includes(subdomain) || cityDomain === normalizedHost;
+        });
+
+        // If we found a matching city or any non-main domain, canonicalize to main domain
+        if (matchedCity || normalizedHost !== "nobat724.com") {
+            // Ensure pathname starts with /
+            const cleanPathname = pathname.startsWith("/") ? pathname : `/${pathname}`;
+            return `${MAIN_DOMAIN}${cleanPathname}`;
+        }
+
+        return null;
+    } catch (error) {
+        console.error("Error generating canonical URL:", error);
+        return null;
+    }
+}
+
+/**
+ * Client-side version for dynamic routes or client components
+ */
+export function getCanonicalUrlClient() {
+    if (typeof window === "undefined") return null;
+
+    try {
+        const host = window.location.host;
+        const pathname = window.location.pathname;
+
+        // Normalize host (remove www and convert to lowercase)
+        const normalizedHost = host.toLowerCase().replace(/^www\./, "");
+
+        // Check if current domain is the main domain
+        if (normalizedHost === "nobat724.com") {
+            return null; // No canonical needed for main domain
+        }
+
+        // Check if this is a subdomain/different domain from our city data
+        const subdomain = normalizedHost.split(".")[0];
+        const matchedCity = citiesData.find((city) => {
+            const cityDomain = city.domain.toLowerCase();
+            return cityDomain.includes(subdomain) || cityDomain === normalizedHost;
+        });
+
+        // If we found a matching city or any non-main domain, canonicalize to main domain
+        if (matchedCity || normalizedHost !== "nobat724.com") {
+            return `${MAIN_DOMAIN}${pathname}`;
+        }
+
+        return null;
+    } catch (error) {
+        console.error("Error generating client canonical URL:", error);
+        return null;
+    }
+}