1. <?php
  3. /**
  4. * Hashes metadata values with limited memory usage.
  5. *
  6. * This function iterates through the metadata values and hashes them
  7. * one at a time to avoid loading the entire dataset into memory.
  8. *
  9. * @param array $metadata An associative array of metadata values.
  10. * @param string $hash_algorithm The hashing algorithm to use (e.g., 'sha256', 'md5').
  11. * @return array An associative array where keys are the original metadata keys
  12. * and values are the corresponding hashes. Returns an empty array on error.
  13. */
  14. function hashMetadata(array $metadata, string $hash_algorithm = 'sha256'): array
  15. {
  16. $hashes = [];
  17. try {
  18. if (!function_exists($hash_algorithm)) {
  19. error_log("Hash algorithm '$hash_algorithm' not found.");
  20. return [];
  21. }
  23. foreach ($metadata as $key => $value) {
  24. if (is_string($value) || is_numeric($value)) { //only hash strings or numbers
  25. $hash = hash($hash_algorithm, $value);
  26. $hashes[$key] = $hash;
  27. } else {
  28. error_log("Skipping non-string/numeric value for key: " . $key);
  29. }
  30. }
  31. } catch (Exception $e) {
  32. error_log("Hashing error: " . $e->getMessage());
  33. return [];
  34. }
  36. return $hashes;
  37. }
  39. // Example usage:
  40. /*
  41. $metadata = [
  42. 'name' => 'Example Metadata',
  43. 'description' => 'This is an example description.',
  44. 'version' => 1.0,
  45. 'author' => 'John Doe',
  46. 'id' => 12345
  47. ];
  49. $hashes = hashMetadata($metadata, 'sha256');
  51. if ($hashes) {
  52. print_r($hashes);
  53. }
  54. */
  56. ?>

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