What is the ruling on trading physical commodities (coffee, sugar, oil, gold, silver) online through a financial intermediary, where the trader does not take physical possession of the goods, but immediate exchange of payment occurs, and no leverage is used?

Possession in all matters is determined by its nature, and custom is given consideration therein. Possession can be physical, by taking hold with the hand or by transfer, or constructive, by vacating the premises while enabling the disposal [of the item]. It varies according to the nature of the items and prevailing customs. Examples of constructive possession include: a bank entry for an amount in a customer's account, and the receipt of a check if it has a withdrawable balance. An agent acts on behalf of his principal in taking possession. Mutual possession at the contract مجلس (session) is not required for coffee, sugar, and oil, whereas it is required for gold and silver. Dealing via the internet with a financial broker in buying and selling gold and silver is permissible if the Sharia (definition) regulations are met and prohibitions are avoided.