Partial download with ftplib and retrbinary

[MRAB]

On May 24, 11:53 am, fepeac... at googlemail.com wrote:
> I am breaking/interrupting my connection with the ftp server at
> present when doing a partial download of a file. I have a callback
> with retrbinary that raises an exception and ends the download. The
> problem is that the server is not notified and hangs. I cannot send
> any further commands and need to relogin to download further. Is there
> a way to still continue downloading without having to login again.
>
> My retrbinary function is:
>
> ftp.retrbinary('RETR '+file, handleDownload,1,bound[0])
>
> where bound[0] is an integer specifying the start byte of the
> download.
>
> My callback is:
>
> def handleDownload(block):
>     global count,localfile,number
>     localfile.write(block)
>     if count==number:
>             raise(Exception)
>     count=count+1
>
> where number specifies the number of bytes to download.
>
> Help would be gratefully received.

Have you tried ftp.abort()? The docs say "Abort a file transfer that
is in progress. Using this does not always work, but it's worth a
try.".

I'd also suggest that you download more than 1 byte at a time, perhaps
1024 (fewer if you're on dial-up).