SendWebMessage

Sends a frame’s page a message - a table, a text, a number or a boolean.

The page’s KcdMp.onMessage handler receives exactly the value sent: a table arrives as an object or an array, a text as a text. The message is written as JSON by JsonEncode, under its rules, and is at most 64 KB of it. A page that is not ready yet is sent it when it is (up to 256 messages or 1 MB are kept per frame; past that the oldest are dropped); messages arrive in the order they were sent. A table with a __kcdmp key at the top is refused: that key is how the game itself talks to a page.

Returns true when the message was handed over, false and the reason when it could not be: "no web layer", "no web interface", "no such frame", "no data" (the value is nil), "reserved key", "too big" or what JsonEncode says about a value it cannot write.

Syntax

SendWebMessage(frame, data)

Parameter	Type
frame	string	the frame’s name
data	table | string | number | boolean	the value the page receives

Returns

true, or false, reason - the reason as a person reads it

Example

-- the HUD page shows the player's speed, a few times a second
local since = 0
function OnFrame(dt)
  since = since + dt
  if since >= 0.25 then
    since = 0
    SendWebMessage("hud", { speed = 3.5 })
  end
end

See also

OnWebEvent · OnWebFrameReady · JsonEncode · the Web interface group of the index