1 files changed, 36 insertions, 0 deletions
diff --git a/server/middleware/cors.go b/server/middleware/cors.go
new file mode 100644
index 0000000..641113a
--- /dev/null
+++ b/server/middleware/cors.go
@@ -0,0 +1,36 @@
+package middleware
+
+import "net/http"
+
+func CORS(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		writeMethods(w, r)
+		writeOrigins(w, r)
+		writeHeaders(w)
+		next.ServeHTTP(w, r)
+	})
+}
+
+func writeMethods(responseWriter http.ResponseWriter, request *http.Request) {
+	method := request.Header.Get("Access-Control-Request-Method")
+	if isPreflight(request) {
+		responseWriter.Header().Add("Access-Control-Allow-Methods", method)
+	}
+}
+
+func writeOrigins(responseWriter http.ResponseWriter, request *http.Request) {
+	origin := request.Header.Get("Origin")
+	if origin == "http://localhost:5173" {
+		responseWriter.Header().Add("Access-Control-Allow-Origin", origin)
+	}
+}
+
+func writeHeaders(responseWriter http.ResponseWriter) {
+	responseWriter.Header().Add("Access-Control-Allow-Headers", "*")
+}
+
+func isPreflight(request *http.Request) bool {
+	return request.Method == "OPTIONS" &&
+		request.Header.Get("Origin") != "" &&
+		request.Header.Get("Access-Control-Request-Method") != ""
+}