feat: Add Varnish caching service and configuration, adjusting Traefik routing and implementing a rate limit middleware.

varnish/default.vcl

@@ -0,0 +1,92 @@
+vcl 4.1;
+
+import std;
+
+backend default {
+    .host = "app";
+    .port = "3000";
+    .first_byte_timeout = 60s;
+}
+
+acl purge {
+    "localhost";
+    "127.0.0.1";
+    "infra"; # Allow purge from within the infra network
+}
+
+sub vcl_recv {
+    # Only allow PURGE from the ACL
+    if (req.method == "PURGE") {
+        if (!client.ip ~ purge) {
+            return (synth(405, "Not allowed."));
+        }
+        return (purge);
+    }
+
+    # Only cache GET and HEAD requests
+    if (req.method != "GET" && req.method != "HEAD") {
+        return (pass);
+    }
+
+    # Bypass cache for Gatekeeper and Directus (already handled by Traefik, but safe to be explicit)
+    if (req.url ~ "^/gatekeeper" || req.url ~ "^/directus" || req.url ~ "^/admin") {
+        return (pass);
+    }
+
+    # Bypass cache for Next.js preview mode / health checks
+    if (req.url ~ "^/api/preview" || req.url ~ "^/health") {
+        return (pass);
+    }
+
+    # Remove all cookies for static files to improve cache hits
+    if (req.url ~ "\.(png|gif|jpg|jpeg|svg|ico|webp|js|css|woff|woff2|otf|ttf)$") {
+        unset req.http.Cookie;
+    }
+
+    # Normalize Cookies: Remove tracking cookies that don't affect page content
+    # This keeps cookies like NEXT_LOCALE or AUTH cookies if needed, but strips others
+    if (req.http.Cookie) {
+        # Strip Google Analytics cookies
+        set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(__utm.|_ga.|_gid.|_gat)(=[^;]*)?", "");
+        # Strip empty cookies
+        set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", "");
+        if (req.http.Cookie ~ "^\s*$") {
+            unset req.http.Cookie;
+        }
+    }
+
+    return (hash);
+}
+
+sub vcl_backend_response {
+    # Cache static assets for a long time
+    if (bereq.url ~ "\.(png|gif|jpg|jpeg|svg|ico|webp|js|css|woff|woff2|otf|ttf)$") {
+        set beresp.ttl = 1w;
+    }
+
+    # Respect Cache-Control from Next.js
+    # If the response should not be cached, Next.js will usually send Cache-Control: no-cache, no-store, etc.
+    if (beresp.http.Cache-Control ~ "private" ||
+        beresp.http.Cache-Control ~ "no-cache" ||
+        beresp.http.Cache-Control ~ "no-store") {
+        set beresp.uncacheable = true;
+        return (deliver);
+    }
+
+    # Set a default TTL if none is provided by the backend
+    if (beresp.ttl <= 0s) {
+        set beresp.ttl = 120s;
+    }
+
+    return (deliver);
+}
+
+sub vcl_deliver {
+    # Add a debug header to show if it was a hit or miss
+    if (obj.hits > 0) {
+        set resp.http.X-Cache = "HIT";
+        set resp.http.X-Cache-Hits = obj.hits;
+    } else {
+        set resp.http.X-Cache = "MISS";
+    }
+}