ftp_nb_get

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

ftp_nb_get — Retrieves a file from the FTP server and writes it to a local file (non-blocking)

Description

ftp_nb_get(
    FTP\Connection $ftp,
    string $local_filename,
    string $remote_filename,
    int $mode = FTP_BINARY,
    int $offset = 0
): int|false

ftp_nb_get() retrieves a remote file from the FTP server, and saves it into a local file.

The difference between this function and ftp_get() is that this function retrieves the file asynchronously, so your program can perform other operations while the file is being downloaded.

Parameters

ftp: An FTP\Connection instance.
local_filename: The local file path (will be overwritten if the file already exists).
remote_filename: The remote file path.
mode: The transfer mode. Must be either FTP_ASCII or FTP_BINARY.
offset: The position in the remote file to start downloading from.

Return Values

Returns FTP_FAILED or FTP_FINISHED or FTP_MOREDATA, or false on failure to open the local file.

Changelog

Version	Description
8.1.0	The `ftp` parameter expects an FTP\Connection instance now; previously, a resource was expected.
7.3.0	The `mode` parameter is now optional. Formerly it has been mandatory.

Examples

Example #1 ftp_nb_get() example

<?php

// Initiate the download
$ret = ftp_nb_get($ftp, "test", "README", FTP_BINARY);
while ($ret == FTP_MOREDATA) {
   
   // Do whatever you want
   echo ".";

   // Continue downloading...
   $ret = ftp_nb_continue($ftp);
}
if ($ret != FTP_FINISHED) {
   echo "There was an error downloading the file...";
   exit(1);
}
?>

Example #2 Resuming a download with ftp_nb_get()

<?php

// Initiate 
$ret = ftp_nb_get($ftp, "test", "README", FTP_BINARY, 
                      filesize("test"));
// OR: $ret = ftp_nb_get($ftp, "test", "README", 
//                           FTP_BINARY, FTP_AUTORESUME);
while ($ret == FTP_MOREDATA) {
   
   // Do whatever you want
   echo ".";

   // Continue downloading...
   $ret = ftp_nb_continue($ftp);
}
if ($ret != FTP_FINISHED) {
   echo "There was an error downloading the file...";
   exit(1);
}
?>

Example #3 Resuming a download at position 100 to a new file with ftp_nb_get()

<?php

// Disable Autoseek
ftp_set_option($ftp, FTP_AUTOSEEK, false);

// Initiate
$ret = ftp_nb_get($ftp, "newfile", "README", FTP_BINARY, 100);
while ($ret == FTP_MOREDATA) {

   /* ... */
   
   // Continue downloading...
   $ret = ftp_nb_continue($ftp);
}
?>

In the example above, newfile is 100 bytes smaller than README on the FTP server because we started reading at offset 100. If we didn't disable FTP_AUTOSEEK, the first 100 bytes of newfile would be '\0'.

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User Contributed Notes 1 note

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-1

passerbyxp at gmail dot com ¶

12 years ago

Note that you may have to keep calling ftp_nb_continue in order to complete the download. For example, if you do this:

<?php
ftp_nb_get($conn,$localfile,$remotefile,FTP_BINARY)
//do some LONG time work
while(ftp_nb_continue($conn)!=FTP_FINISHED){}
?>

Your local file may only contains a few kilobytes and the later ftp_nb_continue will keep raising warning of no more data (due to connection time out, I guess).

So you may want to do this instead:

<?php
$dl=ftp_nb_get($conn,$localfile,$remotefile,FTP_BINARY)
//part of long time work
if(ftp_nb_continue($conn)==FTP_MOREDATA) {}
//part of long time work
if(ftp_nb_continue($conn)==FTP_MOREDATA) {}
//continue to do this until you finish the long time work
while(ftp_nb_continue($conn)==FTP_MOREDATA){}
?>

This happened on my Windows XP + PHP 5.3.8 under CLI. Hope this helps someone.