[zeromq-dev] EOF on file transfer

[Pieter Hintjens]

There is an explanation of how to do file transfer in the Guide, chapter 7.

On Tue, Dec 9, 2014 at 5:46 PM, Tiago Hillebrandt
<tiagohillebrandt at ubuntu.com> wrote:
> Hey guys,
>
> I am using the below Python code to transfer big files between a server and
> a client.
>
> Implementation to send file, server
>
>     CHUNK_SIZE = 250000
>
>     message = pair.recv() # message is the path to the file
>
>     filename = open(message, 'rb')
>     filesize = os.path.getsize(message)
>
>     offsets = (int(ceil(filesize / CHUNK_SIZE)), 0)[filesize <= CHUNK_SIZE]
>
>     for offset in range(offsets + 1):
>         filename.seek(offset)
>
>         chunksize = CHUNK_SIZE
>
>         if offset == offsets:
>             chunksize = filesize - (CHUNK_SIZE * (offset - 1)) # calculate
> the size of the last chunk
>
>         data = filename.read(chunksize)
>
>         pair.send(data)
>
>     pair.send(b'')
>
> Implementation to receive file, client
>
> while True:
>     data = pairs.recv()
>
>     if data is not '':
>         target.write(data)
>     else:
>         break
>
> However, after transfer a big file using this implementation, for some
> reason an extra data is being added at end of the file:
>
> File server side
>
> $ stat file.zip
>   File: `file.zip'
>   Size: 1503656416  Blocks: 2936840    IO Block: 4096   regular file
>
> Client side
>
> $ stat file.zip
>   File: `file.zip'
>   Size: 1503906416  Blocks: 2937328    IO Block: 4096   regular file
>
> The size and blocks are different between them.
>
> That said, do you have any suggestions to calculate/send the end of file
> properly?
>
> Thanks!
>
> --
> Tiago Hillebrandt
> Ubuntu Member
> Ubuntu Brazilian Community Council Member
>
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