PHP 7.4正常的SSH2 SFTP脚本在PHP 8.1中报fopen错误

我使用以下脚本配合定时任务，将公网网站生成的XML文件通过SFTP上传至服务器。该脚本在PHP 7.4（SSH2 v1.2）中运行正常，但在PHP 8.1.16（SSH2 v1.3.1）中会持续加载无法完成，也无错误返回。

更新：排查后定位到问题出在fopen函数。

ini_set('display_startup_errors', 1);
ini_set('display_errors', 1);
error_reporting(-1);

$file = "MYTempFiles/myXML.xml";
$returnFile = file_put_contents($file, file_get_contents('https://www.example.com/myXML'), LOCK_EX);
$sftpFile = "/username/myXML.xml";
if($returnFile === false) {
  die('<p class="center">There was an error processing the XML file.</p>');
}
else {
  echo "<p>$returnFile bytes written to file.</p>";
  echo "\r
<p>request-" . time()."</p>";
}

$sftp_server = "sftp.example.com";
$sftp_userpass = "example_pwd";
$sftp_username = "example_username";
$sftp_port ="2245";

class SFTPConnection
{
    private $connection;
    private $sftp;

    public function __construct($host, $port)
    {
        $this->connection = ssh2_connect($host, $port);
        if (! $this->connection)
            throw new Exception("Could not connect to $host on port $port.");
    }

    public function login($username, $password)
    {
        if (! ssh2_auth_password($this->connection, $username, $password))
            throw new Exception("Could not authenticate with username $username " .
                                "and password $password.");

        $this->sftp = ssh2_sftp($this->connection);
        if (! $this->sftp)
            throw new Exception("Could not initialize SFTP subsystem.");
    }

    public function uploadFile($local_file, $remote_file)
    {
        $sftp = $this->sftp;
        $sftp = (int)$sftp;   
        $stream = fopen("ssh2.sftp://$sftp$remote_file", 'w');
          
        if (! $stream)
            throw new Exception("Could not open file: $remote_file");

        $data_to_send = file_get_contents($local_file);
        if ($data_to_send === false)
            throw new Exception("Could not open local file: $local_file.");

        if (fwrite($stream, $data_to_send) === false)
            throw new Exception("Could not send data from file: $local_file.");

        fclose($stream);
    }
}

try
{
    $mySftp = new SFTPConnection($sftp_server, $sftp_port);
    $mySftp->login($sftp_username, $sftp_userpass);
    $mySftp->uploadFile($file, $sftpFile);
}
catch (Exception $e)
{
    echo $e->getMessage() . "\n";
}

开启错误调试并移除@抑制符后，得到如下警告：

Warning: fopen(): Unable to open ssh2.sftp://6/username/myXML.xml on remote host in /filepath_goes_here/sftp-xml-file.php on line 51

Warning: fopen(ssh2.sftp://6/username/myXML.xml): Failed to open stream: operation failed in /filepath_goes_here/sftp-xml-file.php on line 51
Could not open file: /username/myXML.xml

已做排查：

• 对比两个PHP版本的phpinfo信息，未发现明显差异
• 确认SFTP连接正常
• 将PHP7.4的SSH2升级到v1.3.1后仍能正常运行，但PHP8.1环境下依旧报错
• 确认PHP8.1的allow_url_fopen设置为on

内容的提问来源于stack exchange，提问作者gprobst