Queries

A query sends a request and gets one reply. The first codec is the request, the second the reply.

Sell = Lync.query(
    Lync.struct({ item = Lync.enum({ "sword", "shield" }) }),
    Lync.struct({ sold = Lync.bool(), earned = Lync.int(0, 1000000) })
),

Answer

The answering side registers one responder, before start. What it returns is the reply.

local PRICES = { sword = 100, shield = 60 }

Net.Sell:onServer(function(request, player)
    return { sold = true, earned = PRICES[request.item] }
end)

Each request runs its responder on its own thread, so a responder may yield. The reply is sent when it returns.

Ask

A client's request yields until the reply arrives or the request ends.

-- After Lync.start():
local ok, reply = Net.Sell:request({ item = "sword" })
if ok and reply.sold then
    print("earned", reply.earned)
end

The server can ask one client. It cannot yield on a client, so it passes a callback.

-- After Lync.start():
Net.Confirm:request(player, { text = "rematch?" }, function(ok, reply)
    if ok then
        print(player.Name, reply.yes)
    end
end)

• Both forms take an optional timeout in seconds as the last argument. The default is 10.
• The request value is checked at the call, which throws if it doesn't fit.
• Only the asked player's answer counts. A reply from anyone else is ignored.

When there is no reply

A request never throws once sent. If it ends without a reply, ok is false, reply is one of four codes, and the third value, detail, holds elapsed, the seconds waited.

reply	When
"timeout"	No reply in time. A request dropped by the other side's validation ends this way.
"unanswered"	No responder, a responder that threw or returned a value the reply codec refuses, a client still joining, or a client with too many requests running.
"leave"	The player on the other side left.
"shutdown"	Lync.close() ran first.

These codes report transport failures. Put your game's failures, such as a missing item, in the reply codec, like sold above, so the asker can read them.

A client may have 64 requests running at once in each namespace. See Limits.