How to transfer files from another server, using FTP, in PHP - php

Question

I am trying to find a way to transfer files from server-to-server. The source server can be any platform, and we may not even really know anything about it except that it supports FTP.
A number of posts I have found on SO recommend using scp, sftp, rsync, or wget for this purpose. Given that this PHP script needs to work every time, and the only thing we know for sure is that the source server supports FTP, how can this be achieved?
I found a couple FTP examples on SO, but they weren't explained very well.
We need to be able to download all files and folders, keeping the same directory structure as well.

Answer 1

I have found a PHP class that makes recursive FTP uploads and downloads easy. It can be found here
The code they used is below (The code at the top is example code for downloads, uploads, and error checking):
<?php // example
set_time_limit(0);
require 'ftp.php';
$ftp = new ftp();
$ftp->conn('host', 'username', 'password');
$ftp->get('download/demo', '/demo'); // download live "/demo" folder to local "download/demo"
$ftp->put('/demo/test', 'upload/vjtest'); // upload local "upload/vjtest" to live "/demo/test"
$arr = $ftp->getLogData();
if ($arr['error'] != "")
echo '<h2>Error:</h2>' . implode('<br />', $arr['error']);
if ($arr['ok'] != "")
echo '<h2>Success:</h2>' . implode('<br />', $arr['ok']);
class ftp {
private $conn, $login_result, $logData, $ftpUser, $ftpPass, $ftpHost, $retry, $ftpPasv, $ftpMode, $verbose, $logPath, $createMask;
// --------------------------------------------------------------------
/**
* Construct method
*
* #param array keys[passive_mode(true|false)|transfer_mode(FTP_ASCII|FTP_BINARY)|reattempts(int)|log_path|verbose(true|false)|create_mask(default:0777)]
* #return void
*/
function __construct()
{
$this->retry = (isset($o['reattempts'])) ? $o['reattempts'] : 3;
$this->ftpPasv = (isset($o['passive_mode'])) ? $o['passive_mode'] : true;
$this->ftpMode = (isset($o['transfer_mode'])) ? $o['transfer_mode'] : FTP_BINARY;
$this->verbose = (isset($o['verbose'])) ? $o['verbose'] : false;
$this->logPath = (isset($o['log_path'])) ? $o['log_path'] : dirname(__FILE__).'\log';
$this->createMask = (isset($o['create_mask'])) ? $o['create_mask'] : 0777;
}
// --------------------------------------------------------------------
/**
* Connection method
*
* #param string hostname
* #param string username
* #param string password
* #return void
*/
public function conn($hostname, $username, $password)
{
$this->ftpUser = $username;
$this->ftpPass = $password;
$this->ftpHost = $hostname;
$this->initConn();
}
// --------------------------------------------------------------------
/**
* Init connection method - connect to ftp server and set passive mode
*
* #return bool
*/
function initConn()
{
$this->conn = ftp_connect($this->ftpHost);
$this->login_result = ftp_login($this->conn, $this->ftpUser, $this->ftpPass);
if($this->conn && $this->login_result)
{
ftp_pasv($this->conn, $this->ftpPasv);
return true;
}
return false;
}
// --------------------------------------------------------------------
/**
* Put method - upload files(folders) to ftp server
*
* #param string path to destionation file/folder on ftp
* #param string path to source file/folder on local disk
* #param int only for identify reattempt, dont use this param
* #return bool
*/
public function put($destinationFile, $sourceFile, $retry = 0)
{
if(file_exists($sourceFile))
{
if(!$this->isDir($sourceFile, true))
{
$this->createSubDirs($destinationFile);
if(!ftp_put($this->conn, $destinationFile, $sourceFile, $this->ftpMode))
{
$retry++;
if($retry > $this->retry)
{
$this->logData('Error when uploading file: '.$sourceFile.' => '.$destinationFile, 'error');
return false;
}
if($this->verbose) echo 'Retry: '.$retry."\n";
$this->reconnect();
$this->put($destinationFile, $sourceFile, $retry);
}
else
{
$this->logData('Upload:'.$sourceFile.' => '.$destinationFile, 'ok');
return true;
}
}
else
{
$this->recursive($destinationFile, $sourceFile, 'put');
}
}
}
// --------------------------------------------------------------------
/**
* Get method - download files(folders) from ftp server
*
* #param string path to destionation file/folder on local disk
* #param string path to source file/folder on ftp server
* #param int only for identify reattempt, dont use this param
* #return bool
*/
public function get($destinationFile, $sourceFile, $retry = 0)
{
if(!$this->isDir($sourceFile, false))
{
if($this->verbose)echo $sourceFile.' => '.$destinationFile."\n";
$this->createSubDirs($destinationFile, false, true);
if(!ftp_get($this->conn, $destinationFile, $sourceFile, $this->ftpMode))
{
$retry++;
if($retry > $this->retry)
{
$this->logData('Error when downloading file: '.$sourceFile.' => '.$destinationFile, 'error');
return false;
}
if($this->verbose) echo 'Retry: '.$retry."\n";
$this->reconnect();
$this->get($destinationFile, $sourceFile, $retry);
}
else
{
$this->logData('Download:'.$sourceFile.' => '.$destinationFile, 'ok');
return true;
}
}
else
{
$this->recursive($destinationFile, $sourceFile, 'get');
}
}
// --------------------------------------------------------------------
/**
* Make dir method - make folder on ftp server or local disk
*
* #param string path to destionation folder on ftp or local disk
* #param bool true for local, false for ftp
* #return bool
*/
public function makeDir($dir, $local = false)
{
if($local)
{
if(!file_exists($dir) && !is_dir($dir))return mkdir($dir, $this->createMask); else return true;
}
else
{
ftp_mkdir($this->conn,$dir);
return ftp_chmod($this->conn, $this->createMask, $dir);
}
}
// --------------------------------------------------------------------
/**
* Cd up method - change working dir up
*
* #param bool true for local, false for ftp
* #return bool
*/
public function cdUp($local)
{
return $local ? chdir('..') : ftp_cdup($this->conn);
}
// --------------------------------------------------------------------
/**
* List contents of dir method - list all files in specified directory
*
* #param string path to destionation folder on ftp or local disk
* #param bool true for local, false for ftp
* #return bool
*/
public function listFiles($file, $local = false)
{
if(!$this->isDir($file, $local))return false;
if($local)
{
return scandir($file);
}
else
{
if(!preg_match('/\//', $file))
{
return ftp_nlist($this->conn, $file);
}else
{
$dirs = explode('/', $file);
foreach($dirs as $dir)
{
$this->changeDir($dir, $local);
}
$last = count($dirs)-1;
$this->cdUp($local);
$list = ftp_nlist($this->conn, $dirs[$last]);
$i = 0;
foreach($dirs as $dir)
{
if($i < $last) $this->cdUp($local);
$i++;
}
return $list;
}
}
}
// --------------------------------------------------------------------
/**
* Returns current working directory
*
* #param bool true for local, false for ftp
* #return bool
*/
public function pwd($local = false)
{
return $local ? getcwd() : ftp_pwd($this->conn);
}
// --------------------------------------------------------------------
/**
* Change current working directory
*
* #param string dir name
* #param bool true for local, false for ftp
* #return bool
*/
public function changeDir($dir, $local = false)
{
return $local ? chdir($dir) : #ftp_chdir($this->conn, $dir);
}
// --------------------------------------------------------------------
/**
* Create subdirectories
*
* #param string path
* #param bool
* #param bool true for local, false for ftp
* #param bool change current working directory back
* #return void
*/
function createSubDirs($file, $last = false, $local = false, $chDirBack = true)
{
if(preg_match('/\//',$file))
{
$origin = $this->pwd($local);
if(!$last) $file = substr($file, 0, strrpos($file,'/'));
$dirs = explode('/',$file);
foreach($dirs as $dir)
{
if(!$this->isDir($dir, $local))
{
$this->makeDir($dir, $local);
$this->changeDir($dir, $local);
}
else
{
$this->changeDir($dir, $local);
}
}
if($chDirBack) $this->changeDir($origin, $local);
}
}
// --------------------------------------------------------------------
/**
* Recursion
*
* #param string destionation file/folder
* #param string source file/folder
* #param string put or get
* #return void
*/
function recursive($destinationFile, $sourceFile, $mode)
{
$local = ($mode == 'put') ? true : false;
$list = $this->listFiles($sourceFile, $local);
if($this->verbose) echo "\n".'Folder: '.$sourceFile."\n";
$this->logData(($mode=='get')?('Download:'):('Upload:').$sourceFile.' => '.$destinationFile, 'ok');
if($this->verbose) print_r($list);
$x=0;
$z=0;
if(count($list)==2)// blank folder
{
if($mode == 'get')
$this->makeDir($destinationFile, true);
if($mode == 'put')
$this->makeDir($destinationFile);
}
foreach($list as $file)
{
if($file == '.' || $file == '..')continue;
$destFile = $destinationFile.'/'.$file;
$srcFile = $sourceFile.'/'.$file;
if($this->isDir($srcFile,$local))
{
$this->recursive($destFile, $srcFile, $mode);
}
else
{
if($local)
{
$this->put($destFile, $srcFile);
}
else
{
$this->get($destFile, $srcFile);
}
}
}
}
// --------------------------------------------------------------------
/**
* Check if is dir
*
* #param string path to folder
* #return bool
*/
public function isDir($dir, $local)
{
if($local) return is_dir($dir);
if($this->changeDir($dir))return $this->cdUp(0);
return false;
}
// --------------------------------------------------------------------
/**
* Save log data to array
*
* #param string data
* #param string type(error|ok)
* #return void
*/
function logData($data, $type)
{
$this->logData[$type][] = $data;
}
// --------------------------------------------------------------------
/**
* Get log data array
*
* #return array
*/
public function getLogData()
{
return $this->logData;
}
// --------------------------------------------------------------------
/**
* Save log data to file
*
* #return void
*/
public function logDataToFiles()
{
if(!$this->logPath) return false;
$this->makeDir($this->logPath, true);
$log = $this->getLogData();
$sep = "\n".date('y-m-d H:i:s').' ';
if($log['error'] != "")
{
$logc = date('y-m-d H:i:s').' '.join($sep,$log['error'])."\n";
$this->addToFile($this->logPath.'/'.$this->ftpUser.'-error.log',$logc);
}
if($log['ok'] != "")
{
$logc = date('y-m-d H:i:s').' '.join($sep,$log['ok'])."\n";
$this->addToFile($this->logPath.'/'.$this->ftpUser.'-ok.log',$logc);
}
}
// --------------------------------------------------------------------
/**
* Reconnect method
*
* #return void
*/
public function reconnect()
{
$this->closeConn();
$this->initConn();
}
// --------------------------------------------------------------------
/**
* Close connection method
*
* #return void
*/
public function closeConn()
{
return ftp_close($this->conn);
}
// --------------------------------------------------------------------
/**
* Write to file
*
* #param string path to file
* #param string text
* #param string fopen mode
* #return void
*/
function addToFile($file, $ins, $mode = 'a')
{
$fp = fopen($file, $mode);
fwrite($fp,$ins);
fclose($fp);
}
// --------------------------------------------------------------------
/**
* Destruct method - close connection and save log data to file
*
* #return void
*/
function __destruct()
{
$this->closeConn();
$this->logDataToFiles();
}
}
// END ftp class
/* End of file ftp.php */
/* Location: ftp.php */

Answer 2

This should be a comment, but its a bit long. Copying a file over FTP using PHP might be as simple as
file_put_contents($fname
, file_get_contents('FTP://ftp.example com/path/afile'));
But what do you know about where your PHP code is running? It may not have the capability to
resolve DNS names
make client connections to other/remote services
create a listening data channel (for non-passive data channel)
And we can't answer these questions for you. Hence your first step is to get a proof of concept up and running using similar code to that above before you start worrying about lots of files, directories and synchronisation.
Why the requirement to implement this in PHP?