Lua Leaderboards

This tutorial shows how to send a score from your game, create a Leaderboard entry from it, and set up a message interceptor/listener to process specific messages sent to the currently authenticated player.

Setting Up your Listener

We'll be listening in for the newHighScore message, which will trigger when our player submits a high score for the Leaderboard.

First we'll create the function that will handle the message:

local function onNewHighScoreMessage(newHighScoreMessage)
print("You earned the highscore in the Leaderboard " .. newHighScoreMessage:getLeaderboardName())
end

The message is received and the Leaderboard name is retrieved then used in a print function.

Bind the function you just made to be invoked each time a newHighScore message is received by the game.

gs.getMessageHandler().setNewHighScoreMessageHandler(onNewHighScoreMessage)

Sending your Player's Score

We'll be using the Event we configured in the previous tutorial to send our player's score to the backend which will process the score and create a Leaderboard entry from it.

local function postScore()
--Build Request
local requestBuilder = gs.getRequestBuilder()
local postScoreRequest = requestBuilder.createLogEventRequest()

--Set values, pay attention to the SCORER variable which is used to send the score to the leaderboard
postScoreRequest:setEventKey("Leaderboard_Scorer")
postScoreRequest:setEventAttribute("SCORER", 1201)

--Send Request
postScoreRequest:send()

end

Once the score has been sent and the high score has been beaten, your player will receive a message congratulating them on beating the high score.

To look at the results of the Leaderboard, create a LeaderboardDataRequest and set the value for entries you want back and the Short Code for the Leaderboard you wish to view:

local function printEntries()
--Build Request
local requestBuilder = gs.getRequestBuilder()
local getEntryRequest = requestBuilder.createLeaderboardDataRequest()

--Set values
getEntryRequest:setLeaderboardShortCode("HIGH_SCORE")
getEntryRequest:setEntryCount(50)

--Process response by printing the entries in the format Username, Score then Rank using a for loop. Use getAttribute() for your custom values
getEntryRequest:send(function(response)
     local entries = response:getData()
     for i, entry in pairs(entries) do
         print(entry:getUserName() , entry:getAttribute("SCORER") , entry:getRank())
     end
end)

end

These are the basics of:

• Message handlers/listeners
• Leaderboard score submission.
• Entry printing.

There are a few more requests that deal with Leaderboards, please check our API documentation for more information.