web: no-store responses + robust theme-link swap (fixes stale-cache 'theme switch stopped working')

1 files changed, 11 insertions, 1 deletions

diff --git a/internal/web/server.go b/internal/web/server.go
index 50bf45d..10401ed 100644
--- a/internal/web/server.go
+++ b/internal/web/server.go
@@ -46,7 +46,17 @@ func NewServer(cfg config.Config) http.Handler {
 	}
 	mux.Handle("GET /static/", http.StripPrefix("/static/", http.FileServer(http.FS(staticSub))))
 
-	return mux
+	return noStore(mux)
+}
+
+// noStore stops the browser caching any lectio-web response, so a rebuilt or
+// reinstalled server never has an old page, base.css or theme.css served from
+// cache (which presents as "switching themes stopped working" after an update).
+func noStore(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Cache-Control", "no-store")
+		h.ServeHTTP(w, r)
+	})
 }
 
 // today is lectio-web's "no ?date=" default, in the YYYY-MM-DD form every