php 获取请求头部

<?php
foreach ($_SERVER as $key => $value) {
    if (strpos($key, 'HTTP_') === 0) {
        $header = str_replace(' ', '-', ucwords(str_replace('_', ' ', strtolower(substr($key, 5)))));
        echo "$header: $value\n";
    }
}
?>

<?php
if (!function_exists('getallheaders')) {
    function getallheaders() {
        $headers = [];
        foreach ($_SERVER as $name => $value) {
            if (substr($name, 0, 5) == 'HTTP_') {
                $headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
            } else if ($name == "CONTENT_TYPE") {
                $headers["Content-Type"] = $value;
            } else if ($name == "CONTENT_LENGTH") {
                $headers["Content-Length"] = $value;
            }
        }
        return $headers;
    }
}

$headers = getallheaders();
print_r($headers);
?>