PHP-将图片上传到图片服务器上都有哪些方法？

Question

如题
用户上传图片后首先是存放在运行程序的服务器的临时目录里，完了再用某种方式上传到图片服务器。
我所用过的只有ftp，请教下大家还有哪些方法啊？根据实际情况该如何选取？

Answer 1

我用过的方法，供参考：
1.在iframe里面用另一表单上传图片，表单地址是图片服务器；

2.同样是上传图片后首先是存放在运行程序的服务器的临时目录里，服务器有一个对图片进行压缩、缩放等处理的shell脚本进程，这个脚本的处理完图片后，通过rsync将处理好的图片推送到图片服。

Answer 2

可以采用程序去处理，参考一下CI的一个类库(Ftp.php),源代码如下：
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 5.1.6 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/

// ------------------------------------------------------------------------

/**
* FTP Class
*
* @package CodeIgniter
* @subpackage Libraries
* @category Libraries
* @author ExpressionEngine Dev Team
* @link http://codeigniter.com/user_guide/libraries/ftp.html
*/
class CI_FTP {

var $hostname = '';
var $username = '';
var $password = '';
var $port = 21;
var $passive = TRUE;
var $debug = FALSE;
var $conn_id = FALSE;

/**
* Constructor - Sets Preferences
*
* The constructor can be passed an array of config values
*/
public function __construct($config = array())
{
if (count($config) > 0)
{
$this->initialize($config);
}

log_message('debug', "FTP Class Initialized");
}

// --------------------------------------------------------------------

/**
* Initialize preferences
*
* @access public
* @param array
* @return void
*/
function initialize($config = array())
{
foreach ($config as $key => $val)
{
if (isset($this->$key))
{
$this->$key = $val;
}
}

// Prep the hostname
$this->hostname = preg_replace('|.+?://|', '', $this->hostname);
}

// --------------------------------------------------------------------

/**
* FTP Connect
*
* @access public
* @param array the connection values
* @return bool
*/
function connect($config = array())
{
if (count($config) > 0)
{
$this->initialize($config);
}

if (FALSE === ($this->conn_id = @ftp_connect($this->hostname, $this->port)))
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_connect');
}
return FALSE;
}

if ( ! $this->_login())
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_login');
}
return FALSE;
}

// Set passive mode if needed
if ($this->passive == TRUE)
{
ftp_pasv($this->conn_id, TRUE);
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* FTP Login
*
* @access private
* @return bool
*/
function _login()
{
return @ftp_login($this->conn_id, $this->username, $this->password);
}

// --------------------------------------------------------------------

/**
* Validates the connection ID
*
* @access private
* @return bool
*/
function _is_conn()
{
if ( ! is_resource($this->conn_id))
{
if ($this->debug == TRUE)
{
$this->_error('ftp_no_connection');
}
return FALSE;
}
return TRUE;
}

// --------------------------------------------------------------------

/**
* Change directory
*
* The second parameter lets us momentarily turn off debugging so that
* this function can be used to test for the existence of a folder
* without throwing an error. There's no FTP equivalent to is_dir()
* so we do it by trying to change to a particular directory.
* Internally, this parameter is only used by the "mirror" function below.
*
* @access public
* @param string
* @param bool
* @return bool
*/
function changedir($path = '', $supress_debug = FALSE)
{
if ($path == '' OR ! $this->_is_conn())
{
return FALSE;
}

$result = @ftp_chdir($this->conn_id, $path);

if ($result === FALSE)
{
if ($this->debug == TRUE AND $supress_debug == FALSE)
{
$this->_error('ftp_unable_to_changedir');
}
return FALSE;
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Create a directory
*
* @access public
* @param string
* @return bool
*/
function mkdir($path = '', $permissions = NULL)
{
if ($path == '' OR ! $this->_is_conn())
{
return FALSE;
}

$result = @ftp_mkdir($this->conn_id, $path);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_makdir');
}
return FALSE;
}

// Set file permissions if needed
if ( ! is_null($permissions))
{
$this->chmod($path, (int)$permissions);
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Upload a file to the server
*
* @access public
* @param string
* @param string
* @param string
* @return bool
*/
function upload($locpath, $rempath, $mode = 'auto', $permissions = NULL)
{
if ( ! $this->_is_conn())
{
return FALSE;
}

if ( ! file_exists($locpath))
{
$this->_error('ftp_no_source_file');
return FALSE;
}

// Set the mode if not specified
if ($mode == 'auto')
{
// Get the file extension so we can set the upload type
$ext = $this->_getext($locpath);
$mode = $this->_settype($ext);
}

$mode = ($mode == 'ascii') ? FTP_ASCII : FTP_BINARY;

$result = @ftp_put($this->conn_id, $rempath, $locpath, $mode);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_upload');
}
return FALSE;
}

// Set file permissions if needed
if ( ! is_null($permissions))
{
$this->chmod($rempath, (int)$permissions);
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Download a file from a remote server to the local server
*
* @access public
* @param string
* @param string
* @param string
* @return bool
*/
function download($rempath, $locpath, $mode = 'auto')
{
if ( ! $this->_is_conn())
{
return FALSE;
}

// Set the mode if not specified
if ($mode == 'auto')
{
// Get the file extension so we can set the upload type
$ext = $this->_getext($rempath);
$mode = $this->_settype($ext);
}

$mode = ($mode == 'ascii') ? FTP_ASCII : FTP_BINARY;

$result = @ftp_get($this->conn_id, $locpath, $rempath, $mode);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_download');
}
return FALSE;
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Rename (or move) a file
*
* @access public
* @param string
* @param string
* @param bool
* @return bool
*/
function rename($old_file, $new_file, $move = FALSE)
{
if ( ! $this->_is_conn())
{
return FALSE;
}

$result = @ftp_rename($this->conn_id, $old_file, $new_file);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$msg = ($move == FALSE) ? 'ftp_unable_to_rename' : 'ftp_unable_to_move';

$this->_error($msg);
}
return FALSE;
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Move a file
*
* @access public
* @param string
* @param string
* @return bool
*/
function move($old_file, $new_file)
{
return $this->rename($old_file, $new_file, TRUE);
}

// --------------------------------------------------------------------

/**
* Rename (or move) a file
*
* @access public
* @param string
* @return bool
*/
function delete_file($filepath)
{
if ( ! $this->_is_conn())
{
return FALSE;
}

$result = @ftp_delete($this->conn_id, $filepath);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_delete');
}
return FALSE;
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Delete a folder and recursively delete everything (including sub-folders)
* containted within it.
*
* @access public
* @param string
* @return bool
*/
function delete_dir($filepath)
{
if ( ! $this->_is_conn())
{
return FALSE;
}

// Add a trailing slash to the file path if needed
$filepath = preg_replace("/(.+?)/*$/", "\1/", $filepath);

$list = $this->list_files($filepath);

if ($list !== FALSE AND count($list) > 0)
{
foreach ($list as $item)
{
// If we can't delete the item it's probaly a folder so
// we'll recursively call delete_dir()
if ( ! @ftp_delete($this->conn_id, $item))
{
$this->delete_dir($item);
}
}
}

$result = @ftp_rmdir($this->conn_id, $filepath);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_delete');
}
return FALSE;
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* Set file permissions
*
* @access public
* @param string the file path
* @param string the permissions
* @return bool
*/
function chmod($path, $perm)
{
if ( ! $this->_is_conn())
{
return FALSE;
}

// Permissions can only be set when running PHP 5
if ( ! function_exists('ftp_chmod'))
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_chmod');
}
return FALSE;
}

$result = @ftp_chmod($this->conn_id, $perm, $path);

if ($result === FALSE)
{
if ($this->debug == TRUE)
{
$this->_error('ftp_unable_to_chmod');
}
return FALSE;
}

return TRUE;
}

// --------------------------------------------------------------------

/**
* FTP List files in the specified directory
*
* @access public
* @return array
*/
function list_files($path = '.')
{
if ( ! $this->_is_conn())
{
return FALSE;
}

return ftp_nlist($this->conn_id, $path);
}

// ------------------------------------------------------------------------

/**
* Read a directory and recreate it remotely
*
* This function recursively reads a folder and everything it contains (including
* sub-folders) and creates a mirror via FTP based on it. Whatever the directory structure
* of the original file path will be recreated on the server.
*
* @access public
* @param string path to source with trailing slash
* @param string path to destination - include the base folder with trailing slash
* @return bool
*/
function mirror($locpath, $rempath)
{
if ( ! $this->_is_conn())
{
return FALSE;
}

// Open the local file path
if ($fp = @opendir($locpath))
{
// Attempt to open the remote file path.
if ( ! $this->changedir($rempath, TRUE))
{
// If it doesn't exist we'll attempt to create the direcotory
if ( ! $this->mkdir($rempath) OR ! $this->changedir($rempath))
{
return FALSE;
}
}

// Recursively read the local directory
while (FALSE !== ($file = readdir($fp)))
{
if (@is_dir($locpath.$file) && substr($file, 0, 1) != '.')
{
$this->mirror($locpath.$file."/", $rempath.$file."/");
}
elseif (substr($file, 0, 1) != ".")
{
// Get the file extension so we can se the upload type
$ext = $this->_getext($file);
$mode = $this->_settype($ext);

$this->upload($locpath.$file, $rempath.$file, $mode);
}
}
return TRUE;
}

return FALSE;
}

// --------------------------------------------------------------------

/**
* Extract the file extension
*
* @access private
* @param string
* @return string
*/
function _getext($filename)
{
if (FALSE === strpos($filename, '.'))
{
return 'txt';
}

$x = explode('.', $filename);
return end($x);
}

// --------------------------------------------------------------------

/**
* Set the upload type
*
* @access private
* @param string
* @return string
*/
function _settype($ext)
{
$text_types = array(
'txt',
'text',
'php',
'phps',
'php4',
'js',
'css',
'htm',
'html',
'phtml',
'shtml',
'log',
'xml'
);

return (in_array($ext, $text_types)) ? 'ascii' : 'binary';
}

// ------------------------------------------------------------------------

/**
* Close the connection
*
* @access public
* @param string path to source
* @param string path to destination
* @return bool
*/
function close()
{
if ( ! $this->_is_conn())
{
return FALSE;
}

@ftp_close($this->conn_id);
}

// ------------------------------------------------------------------------

/**
* Display error message
*
* @access private
* @param string
* @return bool
*/
function _error($line)
{
$CI =& get_instance();
$CI->lang->load('ftp');
show_error($CI->lang->line($line));
}

}
// END FTP Class

/* End of file Ftp.php /
/ Location: ./system/libraries/Ftp.php */

具体使用：http://codeigniter.org.cn/user_guide/libraries/ftp.html