如何使用 PHP 检查远程服务器上是否存在文件？

一些建议：

• 使用 ，如果不存在，则返回 -1：http://www.php.net/manual/en/function.ftp-size.phpftp_size
• 使用 ，例如 fopen（“ftp://user:password@example.com/somefile.txt”，“r”）fopen
• 使用 ，检查所需的文件名是否在列表中：http://www.php.net/manual/en/function.ftp-nlist.phpftp_nlist

我用了这个，稍微容易一点：

// the server you wish to connect to - you can also use the server ip ex. 107.23.17.20
        $ftp_server = "ftp.example.com";

// set up a connection to the server we chose or die and show an error
        $conn_id = ftp_connect($ftp_server) or die("Couldn't connect to $ftp_server");
        ftp_login($conn_id,"ftpserver_username","ftpserver_password");

// check if a file exist
        $path = "/SERVER_FOLDER/"; //the path where the file is located

        $file = "file.html"; //the file you are looking for

        $check_file_exist = $path.$file; //combine string for easy use

        $contents_on_server = ftp_nlist($conn_id, $path); //Returns an array of filenames from the specified directory on success or FALSE on error. 

// Test if file is in the ftp_nlist array
        if (in_array($check_file_exist, $contents_on_server)) 
        {
            echo "<br>";
            echo "I found ".$check_file_exist." in directory : ".$path;
        }
        else
        {
            echo "<br>";
            echo $check_file_exist." not found in directory : ".$path;  
        };

        // output $contents_on_server, shows all the files it found, helps for debugging, you can use print_r() as well
        var_dump($contents_on_server);

// remember to always close your ftp connection
        ftp_close($conn_id);

使用的功能：（感谢middaparka）

1. 使用ftp_connect登录

2. 通过ftp_nlist获取远程文件列表

3. 使用in_array查看数组中是否存在该文件