How to print the SSH host key as a client

[Jente Hidskes]

Hey folks,

I am working on a small SFTP client using libssh2. I would like for
this client to persist the host key of the server it is connecting to,
but I seem to be unable to get a hold of it.

After initialising libssh2 and calling libssh2_session_handshake, I am
able to print the host key fingerprint through libssh2_hostkey_hash as
in the example programs. I assumed I would be able to print the actual
host key rather than the fingerprint with libssh2_session_hostkey, but
that returns an empty string.

I suspect that libssh2_session_hostkey only returns the local host key
when operating as a server (given this[1] source code comment), but
the docs[2] are unclear about this: they just state "get the remote
key" and "returns a pointer to the current host key".

Am I doing something wrong, or is it indeed impossible right now to
print the host key when operating as a client?

Kind regards,

Jente

[1] https://github.com/libssh2/libssh2/blob/2a2aaed3b6c3c1dc25e35e11afcfb23f88a18510/src/libssh2_priv.h#L628
[2] https://www.libssh2.org/libssh2_session_hostkey.html