nois 0.4.2

The Nois standard library
Documentation

Nois standard library

nois on crates.io nois on docs.rs

Use this library to integrate your app with the a nois proxy.

Storing the proxy address

#[entry_point]
pub fn instantiate(
    deps: DepsMut,
    _env: Env,
    _info: MessageInfo,
    msg: InstantiateMsg,
) -> Result<Response, ContractError> {
    let nois_proxy_addr = deps
        .api
        .addr_validate(&msg.nois_proxy)
        .map_err(|_| ContractError::InvalidProxyAddress)?;
    NOIS_PROXY.save(deps.storage, &nois_proxy_addr)?;
    Ok(Response::new()
        .add_attribute("action", "instantiate")
        .add_attribute("nois_proxy", msg.nois_proxy))
}

Sending a request

use nois::ProxyExecuteMsg;

pub fn execute_estimate_pi(
    deps: DepsMut,
    _env: Env,
    _info: MessageInfo,
    job_id: String,
) -> Result<Response, ContractError> {
    let nois_proxy = NOIS_PROXY.load(deps.storage)?; // Nois proxy address stored in init

    let res = Response::new().add_message(WasmMsg::Execute {
        contract_addr: nois_proxy.into(),
        msg: to_binary(&ProxyExecuteMsg::GetNextRandomness {
            callback_id: Some(job_id),
        })?,
        funds: vec![],
    });
    Ok(res)
}

Processing the callback

Create a ExecuteMsg enum case called Receive

use cosmwasm_schema::{cw_serde, QueryResponses};

use nois::NoisCallbackMsg;

#[cw_serde]
pub enum ExecuteMsg {
    // ...

    Receive(NoisCallbackMsg),
}

and use it:

#[entry_point]
pub fn execute(
    deps: DepsMut,
    env: Env,
    info: MessageInfo,
    msg: ExecuteMsg,
) -> Result<Response, ContractError> {
    match msg {
        // ...

        ExecuteMsg::Receive(NoisCallbackMsg {
            id: callback_id,
            randomness,
        }) => execute_receive(deps, env, info, callback_id, randomness),
    }
}

// ...

pub fn execute_receive(
    deps: DepsMut,
    _env: Env,
    _info: MessageInfo,
    callback_id: String,
    randomness: Data,
) -> Result<Response, ContractError> {
    let randomness: [u8; 32] = randomness
        .to_array()
        .map_err(|_| ContractError::InvalidRandomness)?;

    // use randomness 🎉
}