feat: add frontend prototype

backend/cmd/api/main.go

@@ -62,7 +62,7 @@ func main() {
 
 	server := &http.Server{
 		Addr:              cfg.BackendAddr,
-		Handler:           mux,
+		Handler:           withCORS(cfg.AppSiteURL, mux),
 		ReadHeaderTimeout: 5 * time.Second,
 	}
 
@@ -103,3 +103,22 @@ func openDatabase(databaseURL string) (*sql.DB, error) {
 
 	return db, nil
 }
+
+func withCORS(allowedOrigin string, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		origin := r.Header.Get("Origin")
+		if origin != "" && origin == allowedOrigin {
+			w.Header().Set("Access-Control-Allow-Origin", allowedOrigin)
+			w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type")
+			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
+			w.Header().Set("Vary", "Origin")
+		}
+
+		if r.Method == http.MethodOptions {
+			w.WriteHeader(http.StatusNoContent)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}