在此处更改您的代码

  $ source_file = $ _FILES ['file'] ['tmp_name']; 
 

这里我已将$ _POST更改为$ _FILES ....

Pulling my hair out a bit here. All I want to do is have a HTML form and then PHP to upload the selected file to a certain directory on an FTP server, but nothing seems to be working correctly.

Here's the html form :

<form action="" enctype="multipart/form-data" method="post">
<input name="file" type="file" />
<input name="submit" type="submit" value="Upload File" />
</form>

And here's the PHP below it (on the same file):

<?php
$ftp_server = "myftp.co.uk";
$ftp_user_name = "myusername";
$ftp_user_pass = "mypass";
$destination_file = "/public_html/my/directory/";
$source_file = $_POST['file']['tmp_name'];

// set up basic connection
$conn_id = ftp_connect($ftp_server);
ftp_pasv($conn_id, true); 

// login with username and password
$login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass); 

// check connection
if ((!$conn_id) || (!$login_result)) { 
    echo "FTP connection has failed!";
    echo "Attempted to connect to $ftp_server for user $ftp_user_name"; 
    exit; 
} else {
    echo "Connected to $ftp_server, for user $ftp_user_name";
}

// upload the file
$upload = ftp_put($conn_id, $destination_file, $source_file, FTP_BINARY); 

// check upload status
if (!$upload) { 
echo "FTP upload has failed!";
} else {
echo "Uploaded $source_file to $ftp_server as $destination_file";
}

// close the FTP stream 
ftp_close($conn_id);
?>

It seems to connect to the FTP ok, but doesn't upload - failed. I'm assuming it's something to do with the way I'm handling the file to be uploaded..?

Also, while I'm here, how do I set the name of the file that's been uploaded as a variable?

Change your code here

$source_file = $_FILES['file']['tmp_name']; 

Here i have changed $_POST to $_FILES....