我一直在尝试使用显式 TLS/SSL 服务器推送到远程 FTP，但连接一直超时。它正在连接，但我不知道它在哪里停止，但我假设它与 FTP/TLS/SSL 控制 channel 有关。任何帮助将不胜感激。

通过 FileZilla，我可以毫无问题地连接，但不能通过 curl。我可能遗漏了一些东西，希望这里的人知道使用 curl 重新创建 session 的最佳方法。这是 FileZilla 的调试输出和我一直在 PHP/curl 中处理的示例代码。这是 PHP 代码，下面是成功的 FileZilla session 的副本。

这里是版本，但我在不同的系统上试过，结果相同。

Curl: v7.43.0

└─(08:04:00 on master ✹)──> php -v                                          ──(Thu,Sep10)─┘
PHP 5.5.27 (cli) (built: Jul 14 2015 17:04:01)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies
    with Xdebug v2.3.3, Copyright (c) 2002-2015, by Derick Rethans

这是实际的代码。

<?php

$server_data = array(
   'transfer_id' => 123456789,
   'post_url' => "ftps://ftps.widgetsltd.com",
   'port' => 21,
   'username' => 'widgetsftp',
   'password' => 'password',
);

$filename = sprintf("%s-%s-%s.csv",
                    $server_data['transfer_id'],
                    microtime(TRUE),
                    rand(1000, 9999));

$temp_filename = sprintf("/tmp/%s", $filename);
$ftp_data = "This is a test";

$fp = fopen($temp_filename, 'w');
fprintf($fp, "%s", $ftp_data);
fclose($fp);

$fp = fopen($temp_filename, 'r');

$ch = curl_init();

curl_setopt($ch, CURLOPT_VERBOSE, TRUE);    
curl_setopt($ch, CURLOPT_URL, sprintf("%s/%s", $server_data['post_url'], $filename));
curl_setopt($ch, CURLOPT_PORT, 21);    
curl_setopt($ch, CURLOPT_USERPWD, sprintf("%s:%s", $server_data['username'], $server_data['password']));

curl_setopt($ch, CURLOPT_UPLOAD, TRUE);
curl_setopt($ch, CURLOPT_INFILE, $fp);
curl_setopt($ch, CURLOPT_INFILESIZE, filesize($temp_filename));

curl_setopt($ch, CURLOPT_USE_SSL, TRUE);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
curl_setopt($ch, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1_0);
curl_setopt($ch, CURLOPT_SSL_CIPHER_LIST, 'AES-128-CBC');

curl_setopt($ch, CURLOPT_FTP_SSL, CURLOPT_FTPSSLAUTH);
curl_setopt($ch, CURLOPT_FTPSSLAUTH, CURLFTPAUTH_TLS);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);

print_r(array('curl_exec' => curl_exec($ch)));
print_r(array(
           'curl_errno' => curl_errno($ch),
           'curl_error' => curl_error($ch),
        ));

这是 FileZilla session 。

Status:        Resolving address of ftps.widgetsltd.com
Status:        Connecting to 123.123.123.123:21...
Status:        Connection established, waiting for welcome message...
Trace:         CFtpControlSocket::OnReceive()
Response:  220-Microsoft FTP Service
Response:  220 Widgets, LTD FTP server
Trace:         CFtpControlSocket::SendNextCommand()
Command:   AUTH TLS
Trace:         CFtpControlSocket::OnReceive()
Response:  234 AUTH command ok. Expecting TLS Negotiation.
Status:        Initializing TLS...
Trace:         CTlsSocket::Handshake()
Trace:         CTlsSocket::ContinueHandshake()
Trace:         CTlsSocket::OnSend()
Trace:         CTlsSocket::OnRead()
Trace:         CTlsSocket::ContinueHandshake()
Trace:         CTlsSocket::OnRead()
Trace:         CTlsSocket::ContinueHandshake()
Trace:         TLS Handshake successful
Trace:         Protocol: TLS1.0, Key exchange: RSA, Cipher: AES-128-CBC, MAC: SHA1
Status:        Verifying certificate...
Status:        TLS connection established.
Trace:         CFtpControlSocket::SendNextCommand()
Command:   USER s-rokfri
Trace:         CTlsSocket::OnRead()
Trace:         CFtpControlSocket::OnReceive()
Response:  331 Password required for s-rokfri.
Trace:         CFtpControlSocket::SendNextCommand()
Command:   PASS ********
Trace:         CTlsSocket::OnRead()
Trace:         CFtpControlSocket::OnReceive()
Response:  230-This service and information contained therein belong to Widgets, LTD.
Response:  230 User logged in.
Trace:         CFtpControlSocket::SendNextCommand()
Command:   OPTS UTF8 ON
Trace:         CTlsSocket::OnRead()
Trace:         CFtpControlSocket::OnReceive()
Response:  200 OPTS UTF8 command successful - UTF8 encoding now ON.
Trace:         CFtpControlSocket::SendNextCommand()
Command:   PBSZ 0
Trace:         CTlsSocket::OnRead()
Trace:         CFtpControlSocket::OnReceive()
Response:  200 PBSZ command successful.
Trace:         CFtpControlSocket::SendNextCommand()
Command:   PROT P
Trace:         CTlsSocket::OnRead()
Trace:         CFtpControlSocket::OnReceive()
Response:  200 PROT command successful.
Status:        Connected
Trace:         CFtpControlSocket::ResetOperation(0)
Trace:         CControlSocket::ResetOperation(0)
Trace:         CFileZillaEnginePrivate::ResetOperation(0)
Trace:         Measured latency of 141 ms
Status:        Retrieving directory listing...
Trace:         CFtpControlSocket::SendNextCommand()
Trace:         CFtpControlSocket::ChangeDirSend()
Command:   PWD
Trace:         CTlsSocket::OnRead()
Trace:         CFtpControlSocket::OnReceive()
Response:  257 "/" is current directory.
Trace:         CFtpControlSocket::ResetOperation(0)
Trace:         CControlSocket::ResetOperation(0)
Trace:         CFtpControlSocket::ParseSubcommandResult(0)
Trace:         CFtpControlSocket::ListSubcommandResult()
Trace:           state = 1
Trace:         CFtpControlSocket::ResetOperation(0)
Trace:         CControlSocket::ResetOperation(0)
Status:        Directory listing of "/" successful
Trace:         CFileZillaEnginePrivate::ResetOperation(0)

这是 curl 输出。

*   Trying 123.123.123.123...
* Connected to ftps.widgetsltd.com (123.123.123.123) port 21 (#0)
* SSL connection timeout
* Closing connection 0
Array
(
    [curl_exec] =>
)
Array
(
    [curl_errno] => 28
    [curl_error] => SSL connection timeout
)

最佳答案

curl 显然尝试使用隐式 FTP(因为它甚至在与服务器交换任何 FTP 命令之前就初始化 TLS/SSL session )。

这是因为您指定了 ftps:// 前缀，该前缀用于隐式 TLS。它具有特殊前缀，因为隐式 TLS 使用特殊端口 (990)。但是您使用 CURLOPT_PORT 覆盖了默认值。

虽然显式 TLS 使用标准的 FTP 端口 (21)，因此它使用标准的 ftp:// 前缀。要启用显式 TLS，请使用 CURLOPT_USE_SSL (你已经在做什么，只是通过一个错误的值，选项类型是枚举，而不是 bool 值)。

所以代码应该是:

$server_data = array(
   ...
   'post_url' => "ftp://ftps.widgetsltd.com", // ftp:// URL
   ...
);

$url = sprintf("%s/%s", $server_data['post_url'], $filename);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_USE_SSL, CURLUSESSL_ALL); // Enable TLS/SSL

请注意，CURLOPT_FTP_SSL 已过时，是 CURLOPT_USE_SSL 的别名。因此，同时设置两者没有意义。

关于带有显式 TLS/SSL 的 PHP curl FTPes，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32491790/