1. /**
  2. * Verifies the integrity of headers metadata for an experiment.
  3. *
  4. * @param {object} headers An object containing the headers metadata.
  5. * @returns {string|null} A success message if headers are valid, or an error message if not. Returns null if headers is invalid.
  6. */
  7. function verifyHeadersMetadata(headers) {
  8. if (!headers || typeof headers !== 'object') {
  9. return "Error: Headers metadata must be an object.";
  10. }
  12. if (typeof headers.timestamp !== 'number') {
  13. return "Error: Timestamp must be a number.";
  14. }
  16. if (typeof headers.version !== 'string' || headers.version.trim() === "") {
  17. return "Error: Version must be a non-empty string.";
  18. }
  20. if (typeof headers.experimentId !== 'string' || headers.experimentId.trim() === "") {
  21. return "Error: Experiment ID must be a non-empty string.";
  22. }
  24. if (headers.signature !== generateSignature(headers)) {
  25. return "Error: Signature does not match the headers metadata.";
  26. }
  29. return null; // Headers metadata is valid.
  30. }
  32. /**
  33. * Generates a signature based on the headers metadata.
  34. * @param {object} headers The headers metadata.
  35. * @returns {string} The generated signature.
  36. */
  37. function generateSignature(headers) {
  38. const str = JSON.stringify(headers); // Convert headers to JSON string.
  39. const hash = crypto.createHash('sha256').update(str).digest('hex'); // Calculate SHA256 hash.
  40. return hash;
  41. }
  45. // Check if crypto is available. This is needed for the signature generation
  46. if (typeof window === 'undefined' || typeof window.crypto === 'undefined') {
  47. console.warn("crypto API is not available in this environment. Signature verification will be disabled.");
  48. generateSignature = () => "Signature generation is disabled";
  49. }
  51. // Example usage (for testing):
  52. // const headers = {
  53. // timestamp: Date.now(),
  54. // version: "1.0",
  55. // experimentId: "myExperiment",
  56. // otherHeader: "someValue"
  57. // };
  59. // const errorMessage = verifyHeadersMetadata(headers);
  60. // if (errorMessage) {
  61. // console.error(errorMessage);
  62. // } else {
  63. // console.log("Headers metadata is valid.");
  64. // }

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