Javascript 为什么这个SFTP下载这么慢？

我在单击时有一个下载按钮，下载一个文件大约需要15秒，因为它必须将SFTP导入服务器，找到正确的路径/文件，然后返回响应

<a class="btn btn-primary btn-sm text-primary btn-download-1" onclick="startDownload('1')"><i class="fa fa-download "></i></a>

/nodes/interface/capture/download

中的后端代码：

public function download_files()
{

    $dir = '';
    $portNumber = Request::get('port');
    $zipMe = false;

    $remotePath = "/home/john/logs/".$dir."/";

    if (!isset($dir) || $dir == null) {
        return redirect()->back()->withInput()->withFlashDanger('SFTP Could not connect.');
    }

    $acsIp =  explode('://', env('ACS_URL'));
    $acsIp =  explode(':',$acsIp[1])[0];
    $sftp = new SFTP($acsIp.':22');

    if (!$sftp->login('john', '***')) {
        return redirect()->back()->withInput()->withFlashDanger('SFTP Could not connect.');
    }

    // Get into the Specified Directory
    $sftpConn = Storage::disk('sftp');

    $SFTPFiles = $sftpConn->allFiles('/'.$dir);

    if ( count($SFTPFiles) > 0 ) {
        foreach ($SFTPFiles as $file) {
            $fileName = $file;
            break;
        }

    } else {
        \Log::info('Files Not found in the Remote!');
        return redirect()->back()->withInput()->withFlashDanger('Files Not found in the Remote!');
    }

    // Create and give 777 permission to remote-files directory
    if (!is_dir(public_path('remote-files/'.$dir))) {
        mkdir(public_path('remote-files/'.$dir), 0777, true);
    }

    $filesToZip = [];

    foreach ( $SFTPFiles as $fileName ) {
        if ( $fileName == '..' || $fileName == '.' ) {
            continue;
        } else if ( $fileName == '' ) {
            \Log::info('File not found');
            continue;
        }

        $fileName     = explode("/", $fileName);
        $onlyFileName = (!empty($fileName) && isset($fileName[1])) ? $fileName[1] : "";
        $filepath = $remotePath.$onlyFileName;

        if (strpos($onlyFileName , $portNumber) !== false) {


            // Download the remote file at specified location in Local
            if (!$sftp->get($filepath, 'remote-files/'.$dir.'/'.$onlyFileName))
            {
                die("Error downloading file ".$filepath);
            }

            $file = public_path('remote-files/'.$dir.'/').$onlyFileName;

            $headers = array(
                'Content-Description: File Transfer',
                'Content-Type: application/octet-stream',
                'Content-Disposition: attachment; filename="'.basename($file).'"',
                'Cache-Control: must-revalidate',
                'Pragma: public',
                'Content-Length: ' . filesize($file)
            );

            return Response::download($file, $onlyFileName, $headers);
        }

        // IF File is exists in Directory
        if ( file_exists( public_path('remote-files/'.$dir.'/').$onlyFileName ) ) {
            $filesToZip[] = public_path('remote-files/'.$dir.'/').$onlyFileName;
            \Log::info('File Generated '.'remote-files/'.$dir.'/'.$onlyFileName);

            // Remove Files from public/remote-files
            $this->removeDirAndFiles('', public_path('remote-files/'.$dir));
            exit;

        } else {
            \Log::info('File not Generated '.'remote-files/'.$dir.'/'.$onlyFileName);
        }
    }
}

这段代码确实有效，但大约需要15秒，这对于用例来说太长了

---

有没有办法加快速度？我的代码是否有问题，或者这是意料之中的事？我应该考虑切换到SCP吗？我应该重新考虑身份验证吗？

我更改了您的函数以测量不同部分的时间，这样您就可以通过查看此字符串“##[time]--”的日志来了解哪个部分减慢了应用程序的速度

---

您是否在代码中的任何位置设置了

$dir

变量？因为就我读它的方式而言，它唯一的内容是，而且永远是，一个空字符串

在其他浏览器中也需要很长时间吗？按下按钮后，浏览器检查器的“网络”选项卡中是否会弹出任何值得注意的内容

此外，也许您可以尝试将函数放在按钮元素中，而不是超链接中
也许这个延迟是浏览器内部的某种超时，因为它希望加载另一个页面

因此，与其使用按钮的超链接，我建议尝试一下：

<button class="btn btn-primary btn-sm text-primary btn-download-1" onclick="startDownload('1')"><i class="fa fa-download "></i></button>

我很想知道会发生什么事。

---

让我们不断更新

您要下载的文件大小是多少？我不知道你是否也面临同样的问题，但不管怎样，看看吧。它的时间都花在哪里了？打开SFTP连接？实际传输文件？档案有多大？您获得的速率（每秒字节数）是多少？文件大小是4kb。如何调试在哪里花费时间？我如何检查传输速率？为什么不使用SFTP随时间或仅差分时间记录每个操作，您将看到每个操作的影响。另外，

$dir

为空，因此远程路径有两个斜杠。@cyber8200用于以这种方式测量时间do，在脚本do$start=time（）的开头；在执行过程中，您可以执行$mid=time（）$花费的时间=$mid-$start；这将为您提供从$start到$mid的秒数，依此类推，您可以迭代以查看哪个间隔花费了大量时间

public function download_files()
{
    $start = time();
    $dir = '';
    $portNumber = Request::get('port');
    $zipMe = false;

    \Log::info("### [TIME] -- t1 =  " . (time() - $start));

    $remotePath = "/home/john/logs/".$dir."/";

    if (!isset($dir) || $dir == null) {
        return redirect()->back()->withInput()->withFlashDanger('SFTP Could not connect.');
    }

    $acsIp =  explode('://', env('ACS_URL'));
    $acsIp =  explode(':',$acsIp[1])[0];

    $t1 = time();

    $sftp = new SFTP($acsIp.':22');

    $t2 = time();
    \Log::info("### [TIME] -- SFTP Instantiation took " . ($t2 - $t1) . " secs");

    if (!$sftp->login('john', '***')) {
        return redirect()->back()->withInput()->withFlashDanger('SFTP Could not connect.');
    }

    $t1 = time();
    // Get into the Specified Directory
    $sftpConn = Storage::disk('sftp');

    $SFTPFiles = $sftpConn->allFiles('/'.$dir);

    $t2 = time();
    \Log::info("### [TIME] -- SFTPFiles list took " . ($t2 - $t1) . " secs");


    // this loop is not clear to me, you basically take the first element and
    // exit the loop
    if ( count($SFTPFiles) > 0 ) {
        foreach ($SFTPFiles as $file) {
            $fileName = $file;
            break;
        }
    } else {
        \Log::info('Files Not found in the Remote!');
        return redirect()->back()->withInput()->withFlashDanger('Files Not found in the Remote!');
}

    $t1 = time();

    // Create and give 777 permission to remote-files directory
    if (!is_dir(public_path('remote-files/'.$dir))) {
        mkdir(public_path('remote-files/'.$dir), 0777, true);
    }

    $t2 = time();
    \Log::info("### [TIME] -- Directory creation took " . ($t2 - $t1) . " secs");

    $filesToZip = [];
    $t1 = time();
    foreach ( $SFTPFiles as $fileName ) 
    {
        $start_loop_time = time();
        \Log::info("### [TIME] -- Loop for $fileName took " . (time() - $t1) . " secs");

        if ( $fileName == '..' || $fileName == '.' ) {
            continue;
        } else if ( $fileName == '' ) {
            \Log::info('File not found');
            continue;
        }

        $fileName     = explode("/", $fileName);
        $onlyFileName = (!empty($fileName) && isset($fileName[1])) ? $fileName[1] : "";
        $filepath = $remotePath.$onlyFileName;

        if (strpos($onlyFileName , $portNumber) !== false) {

             $responseCreationStart = time();
            // Download the remote file at specified location in Local
            if (!$sftp->get($filepath, 'remote-files/'.$dir.'/'.$onlyFileName))
            {
                die("Error downloading file ".$filepath);
            }

            $file = public_path('remote-files/'.$dir.'/').$onlyFileName;

            $headers = array(
                'Content-Description: File Transfer',
                'Content-Type: application/octet-stream',
                'Content-Disposition: attachment; filename="'.basename($file).'"',
                'Cache-Control: must-revalidate',
                'Pragma: public',
                'Content-Length: ' . filesize($file)
            );
            $responseCreationEnd = time();
            \Log::info("### [TIME] -- Response creation took " . ($responseCreationEnd  - $responseCreationStart ) . " secs");
            return Response::download($file, $onlyFileName, $headers);

        }

        // IF File is exists in Directory
        if ( file_exists( public_path('remote-files/'.$dir.'/').$onlyFileName ) ) {
            $t3 = time();
            $filesToZip[] = public_path('remote-files/'.$dir.'/').$onlyFileName;
            \Log::info('File Generated '.'remote-files/'.$dir.'/'.$onlyFileName);

            // Remove Files from public/remote-files
            $this->removeDirAndFiles('', public_path('remote-files/'.$dir));
            $t4 = time();
            \Log::info("### [TIME] -- Deletion took " . ($t4 - $t3) . " secs");
            exit;

        } else {
            \Log::info('File not Generated '.'remote-files/'.$dir.'/'.$onlyFileName);
        }

        \Log::info("### [TIME] -- Loop end reached in  " . (time() - $start_loop_time ) . " secs");
    }
}

<button class="btn btn-primary btn-sm text-primary btn-download-1" onclick="startDownload('1')"><i class="fa fa-download "></i></button>