update

cmd/backoffice/fileserver.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"io/fs"
 	"net/http"
 	"os"
@@ -156,6 +157,34 @@ func (fs *FileServer) CartsHandler(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+func (fs *FileServer) PromotionsHandler(w http.ResponseWriter, r *http.Request) {
+	fileName := filepath.Join(fs.dataDir, "promotions.json")
+	if r.Method == http.MethodGet {
+		file, err := os.Open(fileName)
+		if err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			return
+		}
+		defer file.Close()
+
+		io.Copy(w, file)
+		return
+	}
+	if r.Method == http.MethodPost {
+		file, err := os.Create(fileName)
+		if err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			return
+		}
+		defer file.Close()
+
+		io.Copy(file, r.Body)
+		return
+	}
+
+	w.WriteHeader(http.StatusMethodNotAllowed)
+}
+
 type JsonError struct {
 	Error string `json:"error"`
 }