1. <?php
  3. /**
  4. * Resolves response header dependencies, handling edge cases.
  5. *
  6. * @param array $dependencies An associative array where keys are header names and values are arrays of dependencies.
  7. * Each inner array contains header names that must be set before the outer header.
  8. * @param array $responseHeaders The existing response headers.
  9. * @return array The resolved response headers.
  10. */
  11. function resolveResponseHeaders(array $dependencies, array $responseHeaders): array
  12. {
  13. $resolvedHeaders = $responseHeaders;
  15. // Iterate through dependencies and resolve them.
  16. foreach ($dependencies as $headerName => $dependenciesArray) {
  17. // Check if the header already exists.
  18. if (isset($resolvedHeaders[$headerName])) {
  19. continue; // Skip if already set
  20. }
  22. $canSetHeader = true;
  24. // Check if all dependencies are set.
  25. foreach ($dependenciesArray as $dependencyName) {
  26. if (!isset($resolvedHeaders[$dependencyName])) {
  27. $canSetHeader = false;
  28. break; // Dependency missing, cannot set the header.
  29. }
  30. }
  32. // Set the header if all dependencies are met.
  33. if ($canSetHeader) {
  34. $resolvedHeaders[$headerName] = 'value'; //Set a default value. Modify as needed.
  35. } else {
  36. // Log a warning or handle the missing dependency as needed.
  37. error_log("Missing dependency for header: " . $headerName);
  38. }
  39. }
  40. return $resolvedHeaders;
  41. }
  43. //Example Usage (testing)
  44. if (PHP_SAPI != 'cli') { // Prevent output in CLI
  45. $dependencies = [
  46. 'X-Custom-Header' => ['X-Required-Header', 'Another-Required-Header'],
  47. 'Content-Type' => ['X-Content-Encoding'],
  48. 'Authorization' => [],
  49. ];
  50. $responseHeaders = [
  51. 'X-Required-Header' => 'someValue',
  52. 'Another-Required-Header' => 'anotherValue',
  53. 'X-Content-Encoding' => 'gzip'
  54. ];
  56. $resolvedHeaders = resolveResponseHeaders($dependencies, $responseHeaders);
  58. print_r($resolvedHeaders);
  59. }
  61. ?>

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