Hints

!! SPOILER ALERT !!

This sections contains solutions to previous section's questions.

HandleMsg

Copy #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)] #[serde(rename_all = "snake_case")] pub enum HandleMsg { Approve { // release some coins - if quantity is None, release all coins in balance quantity: Option<Vec<Coin>>, }, Refund {}, Steal { destination: HumanAddr, }, }

Adding Handler

Add a global constant:

Copy // this will be the bech32-encoded address in final code // we cannot use HumanAddr in const as that is heap allocated... use `HumanAddr::from() later const THIEF: &str = "changeme";

Update the match statement in handle:

Copy match msg { HandleMsg::Approve { quantity } => try_approve(deps, env, state, quantity), HandleMsg::Refund {} => try_refund(deps, env, state), HandleMsg::Steal { destination } => try_steal(deps, env, state, destination), }

Implement try_steal:

Copy fn try_steal<S: Storage, A: Api, Q: Querier>( deps: &mut Extern<S, A, Q>, env: Env, _state: State, destination: HumanAddr, ) -> HandleResult { if env.message.sender != HumanAddr::from(THIEF) { Err(StdError::unauthorized()) } else { let contract_address = env.contract.address; let amount = deps.querier.query_all_balances(&contract_address)?; let log = vec![log("action", "safe cracked"), log("to", destination.as_str())]; let r = HandleResponse { messages: vec![CosmosMsg::Bank(BankMsg::Send { from_address: contract_address, to_address: destination, amount, })], log, data: None, }; Ok(r) } }

Note that we have to manually create the send_token logic, as destination is HumanAddr not CanonicalAddr. The distinction can force more code, but it ensures correctness. Note that you will have to update the imports now. Go up to the top of the file and add HumanAddr:

Copy use cosmwasm_std::{ log, to_binary, Api, BankMsg, Binary, CanonicalAddr, Coin, CosmosMsg, Env, Extern, HandleResponse, HandleResult, HumanAddr, InitResponse, InitResult, Querier, StdError, StdResult, Storage, };

Test Steal

Copy #[test] fn handle_steal() { let mut deps = mock_dependencies(20, &[]); // initialize the store let init_amount = coins(1000, "earth"); let init_env = mock_env_height("creator", &init_amount, 876, 0); let msg = init_msg_expire_by_height(1000); let init_res = init(&mut deps, init_env, msg).unwrap(); assert_eq!(0, init_res.messages.len()); // balance changed in init deps.querier.update_balance(MOCK_CONTRACT_ADDR, init_amount); // not just "anybody" can steal the funds let msg = HandleMsg::Steal { destination: HumanAddr::from("bankvault"), }; let env = mock_env_height("anybody", &[], 900, 0); let handle_res = handle(&mut deps, env, msg.clone()); assert!(handle_res.is_err()); // only the master thief let msg = HandleMsg::Steal { destination: HumanAddr::from("hideout"), }; let env = mock_env_height(THIEF, &[], 900, 0); let handle_res = handle(&mut deps, env, msg.clone()).unwrap(); assert_eq!(1, handle_res.messages.len()); let msg = handle_res.messages.get(0).expect("no message"); assert_eq!( msg, &CosmosMsg::Bank(BankMsg::Send { from_address: HumanAddr::from(MOCK_CONTRACT_ADDR), to_address: HumanAddr::from("hideout"), amount: coins(1000, "earth"), }) ); }

You will also have to add MOCK_CONTRACT_ADDR to the test imports, like:

Copy use cosmwasm_std::testing::{mock_dependencies, mock_env, MOCK_CONTRACT_ADDR};