ssh2_connect causes Error 324 (net::ERR_EMPTY_RESPONSE): - php

Question

While trying to list the files present in a remote sftp location using php, I get this error:
Error 324 (net::ERR_EMPTY_RESPONSE):
The server closed the connection without sending any data. On my another lamp server the same code works fine. Please point where I am missing something if you can help please. Thanks in advance.
function listBuildFiles() {
global $sftp_host, $sftp_username, $sftp_password, $sftp_path;
$connection = ssh2_connect($sftp_host);
// Authenticate
if (!ssh2_auth_password($connection, $sftp_username, $sftp_password)) {
throw new Exception('Unable to connect.');
}
// Create our SFTP resource
if (!$sftp = ssh2_sftp($connection)) {
throw new Exception('Unable to create SFTP connection.');
}
/**
* Now that we have our SFTP resource, we can open a directory resource
* to get us a list of files. Here we will use the $sftp resource in
* our address string as I previously mentioned since our ssh2://
* protocol allows it.
*/
$files = array();
$dirHandle = opendir("ssh2.sftp://$sftp$sftp_path");
$i=0;
// Properly scan through the directory for files, ignoring directory indexes (. & ..)
while (false !== ($file = readdir($dirHandle))) {
if ($file != '.' && $file != '..') {
$files[$i] = $file;
$i++;
}
}
echo '<select name="buildName">';
echo '<option>Please Select a build</option>';
foreach ($files as $filename) {
echo "<option value=\"$filename\">$filename</option>";
}
echo '</select>';
ssh2_exec($connection, "exit");
Thanks,
Ujjwal

Answer 1

Just to make sure there is no problem on the server side you can open a console and try a raw ssh connection in verbose mode:
ssh -v youruser#yourhost.com
this traces all the interactions between server and client, maybe gives you some clue from the server side.

Answer 2

With phpseclib, a pure PHP SFTP implementation, you can see the full logs of what's going on. Example:
<?php
include('Net/SFTP.php');
define('NET_SSH2_LOGGING', NET_SSH2_LOG_COMPLEX);
$sftp = new Net_SFTP('www.domain.tld');
if (!$sftp->login('username', 'password')) {
exit('Login Failed');
}
// puts a three-byte file named filename.remote on the SFTP server
$sftp->put('filename.remote', 'xxx');
echo $ssh->getLog();
print_r($ssh->getErrors());
?>
The developer of phpseclib is pretty proactive about providing support too so if you can't figure it out from the logs or error messages (s)he probably can.