test.php

<?php
// https://gist.github.com/magnetikonline/650e30e485c0f91f2f40
class DumpHTTPRequestToFile {
 public function execute($targetFile) {
  $data = sprintf(
   "%s %s %s\n\nHTTP headers:\n",
   $_SERVER['REQUEST_METHOD'],
   $_SERVER['REQUEST_URI'],
   $_SERVER['SERVER_PROTOCOL']
  );
  foreach ($this->getHeaderList() as $name => $value) {
   $data .= $name . ': ' . $value . "\n";
  }
  $data .= "\nRequest body:\n";
  file_put_contents(
   $targetFile,
   $data . file_get_contents('php://input') . "\n"
  );
  echo("Done!\n\n");
 }
 private function getHeaderList() {
  $headerList = [];
  foreach ($_SERVER as $name => $value) {
   if (preg_match('/^HTTP_/',$name)) {
    // convert HTTP_HEADER_NAME to Header-Name
    $name = strtr(substr($name,5),'_',' ');
    $name = ucwords(strtolower($name));
    $name = strtr($name,' ','-');
    // add to list
    $headerList[$name] = $value;
   }
  }
  return $headerList;
 }
}
(new DumpHTTPRequestToFile)->execute('bc.txt');