GetPlayerByUserId

Unsafe

For thread safety, this property is not safe to read in an unsynchronized thread.

Function of:

Description:

This function searches each Player|player in Players for one whose Player/UserId matches the given UserId. If such a player does not exist, it simply returns nil. It is equivalent to the following function:

local Players = game:GetService("Players")
local function getPlayerByUserId(userId)
	for _, player in pairs(Players:GetPlayers()) do
		if player.UserId == userId then
			return player
		end
	end
end

This method is useful in finding the purchaser of a developer product using MarketplaceService/ProcessReceipt, which provides a table that includes the purchaser’s UserId and not a reference to the Player object itself. Most games will require a reference to the player in order to grant products.

Parameters

Name	Type	Default	Description
Name userId	Type int64	Default	Summary The `Player/UserId` of the player being specified

Returns

Return Type	Summary
Return Type Player	Summary

Code Samples

ProcessReceipt Callback

This code sample illustrates a MarketplaceService/ProcessReceipt|ProcessReceipt callback function for a game to handle purchasing of two Articles/Developer Products In Game Purchases|developer products (more can be added as needed). It properly checks for and records purchases using a GlobalDataStore called “PurchaseHistory.”

Most importantly, it properly returns Enum.ProductPurchaseDecision.PurchaseGranted when the transaction is successfully completed or if it’s detected that the purchase has already been granted using the “PurchaseHistory” data store.

			
			
				ProcessReceipt Callback

			
			
			
				Expected Output
			
			
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			local MarketplaceService = game:GetService("MarketplaceService")
local DataStoreService = game:GetService("DataStoreService")
local Players = game:GetService("Players")

-- Data store for tracking purchases that were successfully processed
local purchaseHistoryStore = DataStoreService:GetDataStore("PurchaseHistory")

-- Table setup containing product IDs and functions for handling purchases
local productFunctions = {}
-- ProductId 123123 for a full heal
productFunctions[123123] = function(receipt, player)
	-- Logic/code for player buying a full heal (may vary)
	if player.Character and player.Character:FindFirstChild("Humanoid") then
		-- Heal the player to full health
		player.Character.Humanoid.Health = player.Character.Humanoid.MaxHealth
		-- Indicate a successful purchase
		return true
	end
end
-- ProductId 456456 for 100 gold
productFunctions[456456] = function(receipt, player)
	-- Logic/code for player buying 100 gold (may vary)
	local stats = player:FindFirstChild("leaderstats")
	local gold = stats and stats:FindFirstChild("Gold")
	if gold then
		gold.Value = gold.Value + 100
		-- Indicate a successful purchase
		return true
	end
end

-- The core 'ProcessReceipt' callback function
local function processReceipt(receiptInfo)

	-- Determine if the product was already granted by checking the data store  
	local playerProductKey = receiptInfo.PlayerId .. "_" .. receiptInfo.PurchaseId

	local success, isPurchaseRecorded = pcall(function()
		return purchaseHistoryStore:UpdateAsync(playerProductKey, function(alreadyPurchased)
			if alreadyPurchased then
				return true
			end

			-- Find the player who made the purchase in the server
			local player = Players:GetPlayerByUserId(receiptInfo.PlayerId)
			if not player then
				-- The player probably left the game
				-- If they come back, the callback will be called again
				return nil
			end

			local handler = productFunctions[receiptInfo.ProductId]

			local success, result = pcall(handler, receiptInfo, player)
			-- If granting the product failed, do NOT record the purchase in datastores.
			if not success or not result then
				error("Failed to process a product purchase for ProductId:", receiptInfo.ProductId, " Player:", player)
				return nil
			end

			-- Record the transcation in purchaseHistoryStore.
			return true
		end)
	end)

	if not success then
		error("Failed to process receipt due to data store error.")
		return Enum.ProductPurchaseDecision.NotProcessedYet
	elseif isPurchaseRecorded == nil then
		-- Didn't update the value in data store.
		return Enum.ProductPurchaseDecision.NotProcessedYet
	else	
		-- IMPORTANT: Tell Roblox that the game successfully handled the purchase
		return Enum.ProductPurchaseDecision.PurchaseGranted
	end
end

-- Set the callback; this can only be done once by one script on the server! 
MarketplaceService.ProcessReceipt = processReceipt
		

			
		

			
				
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Players:GetPlayerByUserId

			
				Players:GetPlayerByUserId

				Expected Output
			
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			local player = game:GetService("Players"):GetPlayerByUserId(1)
 
if player then
    print("Player with userId 1 is in this server! Their name is: " .. player.Name)
else
    print("Player with userId 1 is not in this server!")
end
		
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