Contract Ownership

The following example implements access control to restrict functionality to a privileged user.

ABI

The interface contains a function to set the owner and a function that only the owner can use.

abi Ownership {
    #[storage(read, write)]
    fn set_owner(owner: Option<Identity>);

    #[storage(read)]
    fn action();
}

Identity

We must keep track of the owner in storage and compare them against the caller via msg_sender().

Initially there is no owner so we'll set them to None.

storage {
    owner: Option<Identity> = None,
}

Implementation

To set the owner one of two conditions must be met:

• There is no owner
• The current owner is calling the function

To call our action() function the caller must be the owner of the contract.

impl Ownership for Contract {
    #[storage(read, write)]
    fn set_owner(owner: Option<Identity>) {
        assert(storage.owner.read().is_none() || storage.owner.read().unwrap() == msg_sender().unwrap());
        storage.owner.write(owner);
    }

    #[storage(read)]
    fn action() {
        assert(storage.owner.read().unwrap() == msg_sender().unwrap());
        // code
    }
}