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Re: Any tips or documentation for writing a new Curl_handler (protocol)?

From: Dan Fandrich <>
Date: Wed, 11 Jul 2018 14:48:57 +0200

On Wed, Jul 11, 2018 at 12:18:39PM +0100, Richard W.M. Jones wrote:
> Personally, I'm not entirely sure that libcurl really maps well to NBD,
> tbh, since NBD is not a "one request per URL" protocol like most other
> libcurl-supported protocols currently are (at least for the most part).

I'd have to agree to this, but for slightly different reasons. libcurl is
designed for transferring files, whether those are bitmapped images, mail
messages, dictionary definitions or anything else. NBD seems to be a low level
protocol for transferring disk blocks. There's a big mismatch between the two
(as your comment above and others indicate) and I suspect you'll find more
problems as you try to implement support. If you were to also add support for
e.g., ext4 and NTFS filesystem code on top of NBD that would be a different
story as the the file transfer paradigm that libcurl is built around would be

I'm not seriously advocating for embedding a bunch of filesystem code into
libcurl but trying to show that to my eyes, NBD isn't really a good match.

Received on 2018-07-11