You can't send HTTP requests to the ROBLOX api so.. and roblox.plus aren't supported anymore so just wondering how to, mostly get their places.
Pretty sure you can't do that.
EDIT: found a proxy that might come in handy: http://rprxy.xyz/
If you want to get the items in a player's inventory, I think you can use this: https://developer.roblox.com/en-us/api-reference/function/MarketplaceService/PlayerOwnsAsset