feat: render local artist images with no foreign key

server/ctrlbase/ctrl.go

@@ -55,6 +55,21 @@ func (c *Controller) Path(rel string) string {
 	return path.Join(c.ProxyPrefix, rel)
 }
 
+func (c *Controller) BaseURL(r *http.Request) string {
+	scheme := firstExisting(
+		"http", // fallback
+		r.Header.Get("X-Forwarded-Proto"),
+		r.Header.Get("X-Forwarded-Scheme"),
+		r.URL.Scheme,
+	)
+	host := firstExisting(
+		"localhost:4747", // fallback
+		r.Header.Get("X-Forwarded-Host"),
+		r.Host,
+	)
+	return fmt.Sprintf("%s://%s", scheme, host)
+}
+
 func (c *Controller) WithLogging(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		// this is (should be) the first middleware. pass right though it
@@ -87,3 +102,12 @@ func (c *Controller) WithCORS(next http.Handler) http.Handler {
 		next.ServeHTTP(w, r)
 	})
 }
+
+func firstExisting(or string, strings ...string) string {
+	for _, s := range strings {
+		if s != "" {
+			return s
+		}
+	}
+	return or
+}