refactor(server): use boxstore helpers and file status consts

- Move box ID validation, file listing/pathing, manifest creation, and uploads to `boxstore`
- Use shared helpers for safe filenames and polling interval env parsing
- Add file status constants to `models` to avoid duplicated magic strings across handlersrefactor(server): use boxstore helpers and file status consts

- Move box ID validation, file listing/pathing, manifest creation, and uploads to `boxstore`
- Use shared helpers for safe filenames and polling interval env parsing
- Add file status constants to `models` to avoid duplicated magic strings across handlers

lib/helpers/mime.go

@@ -0,0 +1,30 @@
+package helpers
+
+import (
+	"io"
+	"mime"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func MimeTypeForFile(path string, filename string) string {
+	if mimeType := mime.TypeByExtension(strings.ToLower(filepath.Ext(filename))); mimeType != "" {
+		return mimeType
+	}
+
+	file, err := os.Open(path)
+	if err != nil {
+		return "application/octet-stream"
+	}
+	defer file.Close()
+
+	buffer := make([]byte, 512)
+	bytesRead, err := file.Read(buffer)
+	if err != nil && err != io.EOF {
+		return "application/octet-stream"
+	}
+
+	return http.DetectContentType(buffer[:bytesRead])
+}