Return received HTTP headers as JSON

json_headers.php

<?
function normalize_header_name ($name)
{
	$name = substr($name, 5);
	$name = str_replace('_', '-', $name);
	$name = strtolower($name);

	return $name;
}

$headers = array();

foreach ($_SERVER as $name => $value)
	if (preg_match('/^HTTP_/', $name)) $headers[normalize_header_name($name)] = $value;

header('Content-type: application/json');
echo json_encode($headers);