use ppk file to connect to sftp in PHP - php

Question

I am having trouble connecting to an SFTP server using a .ppk file that are provided.
I have tried this ppk file in Filezilla and it works.
According to one of the comments in another question it is better to use phpseclib but i didnt find any instructions on how to download files from SFTP using a ppk file. Any directions or suggestions?
Here is the code I'm not sure if that will help or not.
include('Net/SSH2.php');
include('Crypt/RSA.php');
include('Net/SFTP.php');
DEFINE('SERVER','sample.sftp.com');
DEFINE('USER','sampleUserName');
DEFINE('KEY','sample_key_22733_priv.ppk');
$sftp = new Net_SFTP(SERVER);
//I guess this password is useless here
//and i will have to use my ppk file here but i don't know how
if (!$sftp->login(USER, 'password')) {
exit('Login Failed');
}
var_dump($sftp->nlist());

Answer 1

phpseclib works perfectly fine with PPK files, assuming they're RSA keys and not DSA keys. Just initialize a Crypt_RSA object and then call loadKey(file_get_contents('path/to/key.ppk')) on that object.
To download files do $sftp->get('/path/to/filename.ext').
Here's your orig code modified to include all this:
<?php
include('Net/SSH2.php');
include('Crypt/RSA.php');
include('Net/SFTP.php');
DEFINE('SERVER','sample.sftp.com');
DEFINE('USER','sampleUserName');
DEFINE('KEY','sample_key_22733_priv.ppk');
$rsa = new Crypt_RSA();
$rsa->loadKey(file_get_contents(KEY));
$sftp = new Net_SFTP(SERVER);
//I guess this password is useless here
//and i will have to use my ppk file here but i don't know how
if (!$sftp->login(USER, $rsa)) {
exit('Login Failed');
}
echo $sftp->get('/path/to/filename.ext');

Answer 2

Update:
As #neubert confirmed, PPK files are supported but you do need to make sure they are RSA as I explained, but you do not need them in OpenSSH format
Convert your PPK to an OpenSSH RSA key. You can convert this using the PuTTYgen executable: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
Once you have it in an RSA key, you can use this with phpseclib: http://phpseclib.sourceforge.net/ssh/auth.html#rsakey