refactor(code): Cleaned-up the code base

lib/boxstore/zip.go

@@ -0,0 +1,50 @@
+package boxstore
+
+import (
+	"archive/zip"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func AddFileToZip(zipWriter *zip.Writer, boxID string, filename string) error {
+	path, ok := SafeBoxFilePath(boxID, filename)
+	if !ok {
+		return fmt.Errorf("Invalid file")
+	}
+	if err := ensureRegularFile(path); err != nil {
+		return err
+	}
+	zipName, ok := safeZipEntryName(filename)
+	if !ok {
+		return fmt.Errorf("Invalid zip entry")
+	}
+
+	source, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	destination, err := zipWriter.Create(zipName)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.Copy(destination, source)
+	return err
+}
+func safeZipEntryName(filename string) (string, bool) {
+	filename = strings.TrimSpace(filename)
+	if filename == "" || filepath.IsAbs(filename) {
+		return "", false
+	}
+
+	cleaned := filepath.ToSlash(filepath.Clean(filename))
+	if cleaned == "." || cleaned == ".." || strings.HasPrefix(cleaned, "../") || strings.HasPrefix(cleaned, "/") {
+		return "", false
+	}
+	return cleaned, true
+}