I have been trying to learn how to use developer products, and from the DevHub’s sample code, it implements datastores in order to keep track of purchases?
After looking at the code, I have some questions.
- In the code, it checks to see if the player has already brought the item using Datastores, and if the item was brought, it returned Enum.ProductPurchaseDecision.PurchaseGranted. Does this mean the player can only purchase this product once and if they try to buy it again, it returns Enum.ProductPurchaseDecision.PurchaseGranted and takes their Robux without giving anything?
- What exactly does Enum.ProductPurchaseDecision.PurchaseGranted do? Does this mean the purchase was successful and Robux will be deducted from the player’s account?
Blockquote
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 purchased = false
local success, errorMessage = pcall(function()
purchased = purchaseHistoryStore:GetAsync(playerProductKey)
end)
-- If purchase was recorded, the product was already granted
if success and purchased then
return Enum.ProductPurchaseDecision.PurchaseGranted
elseif not success then
error("Data store error:" .. errorMessage)
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 Enum.ProductPurchaseDecision.NotProcessedYet
end
-- Look up handler function from 'productFunctions' table above
local handler = productFunctions[receiptInfo.ProductId]
-- Call the handler function and catch any errors
local success, result = pcall(handler, receiptInfo, player)
if not success or not result then
warn("Error occurred while processing a product purchase")
print("\nProductId:", receiptInfo.ProductId)
print("\nPlayer:", player)
return Enum.ProductPurchaseDecision.NotProcessedYet
end
-- Record transaction in data store so it isn't granted again
local success, errorMessage = pcall(function()
purchaseHistoryStore:SetAsync(playerProductKey, true)
end)
if not success then
error("Cannot save purchase data: " .. errorMessage)
end
-- IMPORTANT: Tell Roblox that the game successfully handled the purchase
return Enum.ProductPurchaseDecision.PurchaseGranted
end
-- Set the callback; this can only be done once by one script on the server!
MarketplaceService.ProcessReceipt = processReceipt