接收请求中的xml文件。代码有什么问题?

有谁能帮我检测以下代码错误吗?它在上显示错误 $headerList = []; 和 (new DumpHTTPRequestToFile)->execute('./dumprequest.txt'); 请帮助我接收xml请求。

    <?php

class DumpHTTPRequestToFile {

    public function execute($targetFile) {
$data="";
        foreach ($this->getHeaderList() as $name => $value) {
            //$data .= $value . "\n";
        }

        $data .= "";

        file_put_contents(
            $targetFile,
            $data . file_get_contents('php://input') . "\n"
        );

        echo("Done");
    }

    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('./dumprequest.txt');
?>

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