Initial commit: ozon-mock Go server

- Mock Ozon Seller API endpoints
- Products, Postings, Finance, Returns, Analytics
- JSON fixtures for testing
- Docker support
- Gitea Actions CI/CD

internal/middleware/auth.go

@@ -0,0 +1,38 @@
+package middleware
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+func Auth(expectedClientID, expectedAPIKey string, next http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		clientID := r.Header.Get("Client-Id")
+		apiKey := r.Header.Get("Api-Key")
+
+		if clientID == "" || apiKey == "" {
+			writeError(w, 401, "missing credentials: Client-Id and Api-Key headers are required")
+			return
+		}
+
+		if expectedClientID != "" && clientID != expectedClientID {
+			writeError(w, 403, "invalid client id")
+			return
+		}
+		if expectedAPIKey != "" && apiKey != expectedAPIKey {
+			writeError(w, 403, "invalid api key")
+			return
+		}
+
+		next(w, r)
+	}
+}
+
+func writeError(w http.ResponseWriter, code int, msg string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(code)
+	json.NewEncoder(w).Encode(map[string]any{
+		"code":    code,
+		"message": msg,
+	})
+}