I've written a cURL plugin for nbdkit, which lets you turn any
HTTP/FTP/SSH/etc source into a network block device:

https://github.com/libguestfs/nbdkit/tree/master/plugins/curl

Currently it works well for read-only connections.

I tried adding write support to the plugin (see attached patch),
however I couldn't get that to work at all.

Can a single cURL handle be "switched" between reading and uploading?
And if so, how do you do that?

Or should the plugin open two handles (one for reading, one for
writing)?

Rich.

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