upload.php

<?php

$inputHandler = fopen('php://input', "r");
$path = realpath(dirname(__FILE__) . '/upload');

$fileHandler = fopen($path . '/' . 'some-name-file', "a+");

while (true) {
    $buffer = fgets($inputHandler, 4096);
    if (strlen($buffer) == 0) {
        fclose($inputHandler);
        fclose($fileHandler);
        break;
    }
    fwrite($fileHandler, $buffer);
}