Merge pull request #21 from ethpandaops/feat/configure-cache-headers

feat: configure cache headers for config, bounds, and proxy endpoints

Author: Savid

internal/api/config.go

@@ -84,7 +84,7 @@ func (h *ConfigHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	// Set headers.
 	w.Header().Set("Content-Type", "application/json")
-	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	w.Header().Set("Cache-Control", "public, max-age=1, s-maxage=60, stale-while-revalidate=300")
 
 	// Encode response
 	if err := json.NewEncoder(w).Encode(response); err != nil {

internal/frontend/frontend.go

@@ -173,10 +173,8 @@ func (f *Frontend) serveIndex(w http.ResponseWriter, r *http.Request) {
 		"content_length": len(html),
 	}).Debug("Serving route-specific cached index.html")
 
-	// Set no-cache headers for index.html
-	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
-	w.Header().Set("Pragma", "no-cache")
-	w.Header().Set("Expires", "0")
+	// Set cache headers for index.html (contains config and bounds data)
+	w.Header().Set("Cache-Control", "public, max-age=1, s-maxage=5, stale-while-revalidate=1")
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	w.WriteHeader(http.StatusOK)
 

internal/proxy/proxy.go

@@ -135,7 +135,7 @@ func (p *Proxy) createReverseProxy(
 		ExpectContinueTimeout: 1 * time.Second,
 	}
 
-	// Create ReverseProxy with Rewrite function
+	// Create ReverseProxy with Rewrite function and response modification
 	proxy := &httputil.ReverseProxy{
 		Rewrite: func(r *httputil.ProxyRequest) {
 			// Set target URL
@@ -176,6 +176,12 @@ func (p *Proxy) createReverseProxy(
 				}).Debug("Transformed slot filters to slot_start_date_time")
 			}
 		},
+		ModifyResponse: func(r *http.Response) error {
+			// Set cache headers for proxy responses
+			r.Header.Set("Cache-Control", "public, max-age=1, s-maxage=5, stale-while-revalidate=1")
+
+			return nil
+		},
 		Transport: transport,
 		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
 			p.logger.WithFields(logrus.Fields{