From 2fcf17aa1dd7f0d46dc65ed2a1ccd35018b2f0c8 Mon Sep 17 00:00:00 2001
From: Daniele Tonon <tonon@vitamino.it>
Date: Fri, 4 Aug 2023 15:40:30 +0200
Subject: [PATCH] Set Cache-Control to 60s on failed fetch

This way we can permit a fast retry while keeping some control on DoS attacks
---
 render.go         | 5 +++++
 render_archive.go | 2 ++
 render_relay.go   | 2 ++
 3 files changed, 9 insertions(+)

diff --git a/render.go b/render.go
index ffb4e9f..a2f5477 100644
--- a/render.go
+++ b/render.go
@@ -57,6 +57,7 @@ func render(w http.ResponseWriter, r *http.Request) {
 	if strings.HasPrefix(code, "note1") {
 		_, redirectHex, err := nip19.Decode(code)
 		if err != nil {
+			w.Header().Set("Cache-Control", "max-age=60")
 			http.Error(w, "error fetching event: "+err.Error(), 404)
 			return
 		}
@@ -75,6 +76,7 @@ func render(w http.ResponseWriter, r *http.Request) {
 	// code can be a nevent, nprofile, npub or nip05 identifier, in which case we try to fetch the associated event
 	event, err := getEvent(r.Context(), code)
 	if err != nil {
+		w.Header().Set("Cache-Control", "max-age=60")
 		http.Error(w, "error fetching event: "+err.Error(), 404)
 		return
 	}
@@ -132,6 +134,7 @@ func render(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 		if err != nil {
+			w.Header().Set("Cache-Control", "max-age=60")
 			http.Error(w, "error fetching event: "+err.Error(), 404)
 			return
 		}
@@ -319,6 +322,8 @@ func render(w http.ResponseWriter, r *http.Request) {
 
 	if (strings.Contains(typ, "profile") && len(renderableLastNotes) != 0) || (!strings.Contains(typ, "profile") && len(content) != 0) {
 		w.Header().Set("Cache-Control", "max-age=604800")
+	} else {
+		w.Header().Set("Cache-Control", "max-age=60")
 	}
 
 	if err := tmpl.ExecuteTemplate(w, templateMapping[typ], params); err != nil {
diff --git a/render_archive.go b/render_archive.go
index 47829cd..5e29e60 100644
--- a/render_archive.go
+++ b/render_archive.go
@@ -66,6 +66,8 @@ func renderArchive(w http.ResponseWriter, r *http.Request) {
 
 	if len(data) != 0 {
 		w.Header().Set("Cache-Control", "max-age=86400")
+	} else {
+		w.Header().Set("Cache-Control", "max-age=60")
 	}
 
 	if err := tmpl.ExecuteTemplate(w, "archive.html", params); err != nil {
diff --git a/render_relay.go b/render_relay.go
index 6cad810..8514935 100644
--- a/render_relay.go
+++ b/render_relay.go
@@ -74,6 +74,8 @@ func renderRelayPage(w http.ResponseWriter, r *http.Request) {
 
 	if len(renderableLastNotes) != 0 {
 		w.Header().Set("Cache-Control", "max-age=604800")
+	} else {
+		w.Header().Set("Cache-Control", "max-age=60")
 	}
 
 	if err := tmpl.ExecuteTemplate(w, templateMapping[typ], params); err != nil {