PHP ftp_nb_fget() 函数

PHP ftp_nb_fget() 函数从 FTP 服务器下载文件，并将其保存到打开的本地文件。

该函数与ftp_fget()的区别在于该函数异步检索文件，这样您的程序就可以在下载文件时执行其他操作。

语法

ftp_nb_fget(ftp, open_file, server_file, 
             mode, offset) 

参数

返回值

返回以下任意值:

• FTP_FAILED:异步传输失败。
• FTP_FINISHED:异步传输已完成。
• FTP_MOREDATA:异步传输仍处于活动状态。

示例:

下面的示例显示了ftp_nb_fget( ) 函数。

<?php
//要使用的FTP服务器
$ftp_server = "ftp.example.com";

//FTP 连接的用户名
$ftp_user = "user";
  
//用户密码
$ftp_pass = "password";
   
//建立连接或者连接失败
$ftp = ftp_connect($ftp_server)
    or die("Could not connect to $ftp_server");
   
if($ftp) {
  echo "Successfully connected to $ftp_server!\n";
 
  //尝试登录
  if(@ftp_login($ftp, $ftp_user, $ftp_pass)) {
    echo "Connected as $ftp_user@$ftp_server\n";

    //本地打开文件指针在其中
    //我们存储数据
    $open_file = fopen("local_demo.txt", "w");
      
    //服务器文件路径
    //需要下载
    $server_file = "server_demo.txt";
      
    //下载指定服务器文件
    //并保存以打开本地文件
    $ret = ftp_nb_fget($ftp, $open_file, 
                    $server_file, FTP_ASCII);

    while ($ret == FTP_MOREDATA) {
      //继续下载...
      $ret = ftp_nb_continue($ftp);
    }

    if ($ret == FTP_FINISHED) {
      echo "Successfully written to $open_file\n";
    } else {
      echo "Error while downloading $server_file\n";
      exit(1);
    }

    //关闭文件指针
    fclose($open_file);
    
  } else {
    echo "Couldn't connect as $ftp_user\n";
  }
 
  //关闭连接
  if(ftp_close($ftp)) {
    echo "Connection closed successfully!\n"; 
  } 
}
?> 

上述代码的输出将是:

Successfully connected to ftp.example.com!
Connected as user@ftp.example.com
Successfully written to local_demo.txt
Connection closed successfully!