使生成密码在SMTPSMTP？

Question

如何隐藏密码smtp gmail？

$config['protocol']     = 'smtp';
$config['smtp_host']    = 'ssl://smtp.gmail.com';
$config['smtp_port']    = '465';
$config['smtp_timeout'] = '7';
$config['smtp_user']    = 'email@gmail.com';
$config['smtp_pass']    = '123';  
$config['charset']      = 'utf-8';
$config['newline']      = "\r\n";
$config['mailtype']     = 'html'
$config['validation']   = TRUE; // bool whether to validate email or not      
$ci->email->initialize($config);
$ci->email->from('email@gmail.com', 'Title');
$ci->email->to(array($data['email'],'email@gmail.com'));

在此处隐藏密码：

$config['smtp_pass'] = '123';  // hide password here