1. /**
  2. * Validates file data for backward compatibility, handling edge cases.
  3. *
  4. * @param {File} file The file to validate.
  5. * @param {string} expectedType The expected file type (e.g., 'text/plain', 'application/json').
  6. * @param {object} options Optional validation parameters.
  7. * @returns {object} An object containing validation results: { valid: boolean, message: string }.
  8. */
  9. function validateFileData(file, expectedType, options = {}) {
  10. if (!file) {
  11. return { valid: false, message: 'File is required.' };
  12. }
  14. const fileType = file.type;
  15. const fileName = file.name;
  16. const fileSize = file.size;
  18. // Check file type. Handle potential MIME type variations.
  19. const isValidType = fileType === expectedType || (options.allowMimeVariations && options.mimeVariations.includes(fileType));
  20. if (!isValidType) {
  21. return { valid: false, message: `Invalid file type. Expected: ${expectedType}, Got: ${fileType}` };
  22. }
  24. // Check file size. Handle very large files to prevent memory issues.
  25. if (options.maxFileSize && fileSize > options.maxFileSize) {
  26. return { valid: false, message: `File size exceeds the limit (${options.maxFileSize} bytes).` };
  27. }
  29. // Check file name (optional). Prevent potentially harmful file names.
  30. if (options.allowedFileNameRegex) {
  31. const regex = new RegExp(options.allowedFileNameRegex);
  32. if (!regex.test(fileName)) {
  33. return { valid: false, message: `Invalid file name. Must match pattern: ${options.allowedFileNameRegex}` };
  34. }
  35. }
  37. //Basic content validation - check if it's at least a certain size
  38. if (options.minFileSize && fileSize < options.minFileSize) {
  39. return {valid: false, message: `File is too small. Minimum size ${options.minFileSize} bytes required.`}
  40. }
  42. return { valid: true, message: 'File is valid.' };
  43. }

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