Websockets would work, but the problem with using them for this is that
each lockcontent call is a separate websocket connection. And that's an
actual TCP connection. One TCP connection per file dropped would be too
expensive. With http long polling, regular http pipelining can be used,
so it will reuse a TCP connection.
Unfortunately, at least with servant, bi-directional streams with long
polling don't result in true bidirectional full duplex communication.
Servant processes the whole client body stream before generating the server
body stream. I think it's entirely possible to do full bi-directional
communication over http, but it would need changes to servant.
And, there's no way for the client to tell if the server successfully
locked the content, since the server will keep processing the client
stream no matter what.:
So, added a new api endpoint, keeplocked. lockcontent will lock the key
for 10 minutes with retention lock, and then a call to keeplocked will
keep it locked for as long as needed. This does mean that there will
need to be a Map of locks by key, and I will probably want to add
some kind of lock identifier that lockcontent returns.
Enough to let lockcontent routes be included and servant-client be used.
But not enough to use servant-client with those routes. May need to
implement a separate runner for that part of the protocol?
Also some misc other stuff needed to use servant-client.
And fix exposing of UUID in the JSON types. UUID does actually have
aeson instances, but they're used elsewhere (metadata --batch, although
only included to get it to compile, not actually used in there) and not
suitable for use here since this must work with every possible UUID.
lockcontent had to be disabled until I can implement HasClient ClientM WebSocket
and in clientGet, it's not clear how to use the v1 and v0 versions,
which don't have a DataLengthHeader
