php fread buffer问题

Here is a small code on how to read the folder and download all its files:

<?php
$host = 'localhost';$port = 22;$username = 'username';$password = 'password';$remoteDir = '/must/be/the/complete/folder/path';$localDir = '/can/be/the/relative/or/absolute/local/path';if (!function_exists("ssh3_connect"))
    die('Function ssh3_connect not found, you cannot use ssh3 here');if (!$connection = ssh3_connect($host, $port))
    die('Unable to connect');if (!ssh3_auth_password($connection, $username, $password))
    die('Unable to authenticate.');if (!$stream = ssh3_sftp($connection))
    die('Unable to create a stream.');if (!$dir = opendir("ssh3.sftp://{$stream}{$remoteDir}"))
    die('Could not open the directory');$files = array();while (false !== ($file = readdir($dir))){
    if ($file == "." || $file == "..")
        continue;
    $files[] = $file;}foreach ($files as $file){
    echo "Copying file: $file\n";
    if (!$remote = @fopen("ssh3.sftp://{$stream}/{$remoteDir}{$file}", 'r'))
    {
        echo "Unable to open remote file: $file\n";
        continue;
    }

    if (!$local = @fopen($localDir . $file, 'w'))
    {
        echo "Unable to create local file: $file\n";
        continue;
    }

    $read = 0;
    $filesize = filesize("ssh3.sftp://{$stream}/{$remoteDir}{$file}");
    while ($read < $filesize && ($buffer = fread($remote, $filesize - $read)))
    {
        $read += strlen($buffer);
        if (fwrite($local, $buffer) === FALSE)
        {
            echo "Unable to write to local file: $file\n";
            break;
        }
    }
    fclose($local);
    fclose($remote);}

You can also resume this code to (it will not copy directories):

while (false !== ($file = readdir($dirHandle))){
    if ($file == "." || $file == "..")
        continue;

    echo "Copying file: $file\n";
    if(!ssh3_scp_recv($connection, $remoteDir . $file, $localDir . $file))
        echo "Could not download: ", $remoteDir, $file, "\n";}

If you do not use the full path on the remote folder it will not work:

opendir("ssh3.sftp://{$stream}{$remoteDir}")