1. <?php
  3. /**
  4. * Function to apply rate limiting to JSON responses.
  5. *
  6. * @param array $data The data to be returned as JSON.
  7. * @param int $limit The maximum number of requests allowed within a time window (in seconds).
  8. * @param int $window The time window in seconds.
  9. * @param string $key The key to store the request timestamp for the user/IP.
  10. * @return array|string The modified data to be returned as JSON, or an error message.
  11. */
  12. function applyRateLimit(array $data, int $limit, int $window, string $key)
  13. {
  14. // Session storage for request timestamps
  15. if (!session_id()) {
  16. session_start();
  17. }
  19. // Check if the user/IP has exceeded the rate limit
  20. if (isset($_SESSION[$key])) {
  21. $lastRequest = $_SESSION[$key];
  22. $currentTime = time();
  24. if ($currentTime - $lastRequest < $window) {
  25. return ['error' => 'Rate limit exceeded. Please try again later.']; // Return an error message
  26. }
  27. }
  29. // Update the request timestamp
  30. $_SESSION[$key] = $currentTime;
  32. return $data; // Return the data
  33. }
  36. /**
  37. * Example usage: Simulate a API endpoint.
  38. *
  39. * @param array $requestData The incoming request data.
  40. * @return string The JSON response.
  41. */
  42. function apiEndpoint(array $requestData): string
  43. {
  44. // Simulate some processing
  45. sleep(0.1);
  47. try {
  48. $data = applyRateLimit($requestData, 10, 5, 'user_request'); // Limit to 10 requests every 5 seconds
  50. //If rate limit is exceeded, apply rate limiting function will return error message.
  51. if(isset($data['error'])){
  52. return json_encode($data); // Return error message as JSON
  53. }
  55. return json_encode($data); // Return the data as JSON
  56. } catch (Exception $e) {
  57. return json_encode(['error' => 'An unexpected error occurred: ' . $e->getMessage()]); // Return error as JSON
  58. }
  59. }
  62. // Example usage (for testing):
  63. if (isset($_POST['data'])) {
  64. $requestData = json_decode($_POST['data'], true);
  65. $response = apiEndpoint($requestData);
  66. echo $response;
  67. }
  69. ?>

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