SFTP put operation fails if used with remote file stream as resource

[mirfilip]

Hi,
I'm using version 2.0.6 of phpseclib via flysystem-sftp (bridge/adapter for flysystem).

I want to "stream" a remote file directly to sftp server, avoiding disk usage on a machine I run the script on. For that, I:

1. fopen a remote file using http stream wrapper
2. Executing SFTP::put with opened remote file handle as $data

$remoteFileStream = fopen(
    'http://www.example.org/someResource.mp4',
    'r'
);
$sftpFilesystem = new \phpseclib\Net\SFTP($host, $port, 30);
$loginSuccess = $sftpFileSystem->login($user, $pass);
if ($loginSuccess) {
   $success = $sftpFilesystem->put('/path/to/remote/file.mp4', $remoteFileStream);
   var_dump($success); // true but empty file is created
}

The result is an empty file created on sftp server.

Reading documentation, I have noticed a SOURCE_LOCAL_FILE mode. I have already seen #1119 which treats about somewhat similar case, but for local files.

Conceptually, I'd expect this case to handle that.

Is that the case that put with remote file as a stream is not supported?

[mirfilip]

Crux of the problem seems to be a failure of reading http stream stats with fstat. It returns false.

There is a disclaimer on docs page:

Note: This function will not work on remote files as the file to be examined must be accessible via the server's filesystem.

A simple snippet to reproduce:

$remoteFileStream = fopen(
    'http://www.example.org/',
    'r'
);
$stats = fstat($remoteFileStream);
var_dump($stats); // false

Of course, handling remote streams bears more questions like resumes via range header, efficiently copying it chunk by chunk, as it's not viable to just copy the remote stream to memory stream.

As this library can create and register a wrapper, I think it'd be possible to open a remote handle for sftp and do: stream_copy_to_stream($remoteFileStream, $sftpFileStream) or equivalent.

[bantu]

There is a stream wrapper for phpseclib's SFTP implementation which you might want to use as a workaround. https://github.com/phpseclib/phpseclib/blob/2.0.6/ phpseclib/Net/SFTP/Stream.php

[mirfilip]

Here is my usage example of stream wrapper:

<?php
$remoteFileStream = fopen(
    'http://www.example.org/,
    'r'
);

$to = "test123.txt";
\phpseclib\Net\SFTP\Stream::register();
$sftpFilesystem = new \phpseclib\Net\SFTP($hostname, $port, 30);
if (!$sftpFilesystem->login($user, $pass)) {
    exit(1);
}

$context = [
    'sftp' => [
        'sftp' => $sftpFilesystem
    ],
];
$sftpStream = fopen("sftp://upload/$to", 'w+', null, stream_context_create($context));
if (!$sftpStream) {
    exit(1);
}

$bytes = stream_copy_to_stream($remoteFileStream, $sftpStream);

if ($bytes > 0) {
 exit(0);
} else {
    exit(1);
}

It indeed works, but file gets uploaded to root directory instead. I'm fiddling with that nuisance now.

[bantu]

Guessing: sftp://host/./path to upload to home/pwd.

[mirfilip]

@bantu 👏
Indeed, changing to fopen("sftp://./upload/$to", 'w+, ...) handles that. I pass host, port, user, pass directly to SFTP instance.

I just wish interaction via Stream wrapper was documented. Maybe I'll contribute with some simplest use case.

Also, how about disallowing using remote streams with SFTP methods if they don't handle them? At very least, I feel it should return success false in that case.

[terrafrost]

deb485c seemed to fix the issue for me.

[mirfilip]

@terrafrost Thank you.

I confirm deb485c fixes the issue.

Now using a stream wrapper and put both work.