Nois standard library

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

Storing the proxy address

```rust

[entry_point]

pub fn instantiate( deps: DepsMut, env: Env, _info: MessageInfo, msg: InstantiateMsg, ) -> Result { let noisproxyaddr = deps .api .addrvalidate(&msg.noisproxy) .maperr(|| ContractError::InvalidProxyAddress)?; NOISPROXY.save(deps.storage, &noisproxyaddr)?; Ok(Response::new() .addattribute("action", "instantiate") .addattribute("noisproxy", msg.noisproxy)) } ```

Sending a request

```rust use nois::ProxyExecuteMsg;

pub fn executeestimatepi( deps: DepsMut, env: Env, _info: MessageInfo, jobid: String, ) -> Result { let noisproxy = NOISPROXY.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 { job_id })?,
    funds: vec![],
});
Ok(res)

} ```

Processing the callback

Create a ExecuteMsg enum case called Receive

```rust use cosmwasmschema::{cwserde, QueryResponses};

use nois::NoisCallback;

[cw_serde]

pub enum ExecuteMsg { // ...

NoisReceive {
    callback: NoisCallback,
},

} ```

and use it:

```rust

[entry_point]

pub fn execute( deps: DepsMut, env: Env, info: MessageInfo, msg: ExecuteMsg, ) -> Result { match msg { // ...

    ExecuteMsg::NoisReceive { callback } => execute_nois_receive(deps, env, info, callback),
}

}

// ...

pub fn executenoisreceive( deps: DepsMut, env: Env, _info: MessageInfo, callback: NoisCallback, ) -> Result { let proxy = NOISPROXY.load(deps.storage)?; ensure_eq!(info.sender, proxy, ContractError::UnauthorizedReceive);

let NoisCallback { job_id, randomness, .. } = callback;
let randomness: [u8; 32] = randomness
    .to_array()
    .map_err(|_| ContractError::InvalidRandomness)?;

// use randomness 🎉

} ```

Build for JavaScript

The Nois Toolbox can be compiled to JavaScript via WebAssembly. This way you can simulate the outputs for every randomness value. The results match exactly those of CosmWasm contracts using the same tools.

In order to keep the JS/Wasm interface simple, there is a wrapper in the module lib/js which takes randomness inputs in hex format and uses types and error handling that plays well with JS. JS/Wasm bindings are created using wasm-bindgen.

The JS does not match 100% the contract implementation. The differences are documented here.

| Contract function | JS function | Status | Note | | ------------------------------ | ---------------------- | -------- | -------------------------------------------------------------------- | | [nois::coinflip] | coinflip | ✅ Ready | Returns string instead of enum | | [nois::roll_dice] | roll_dice | ✅ Ready | | | [nois::int_in_range] | int_in_range | ✅ Ready | Only supports safe integer range | | [nois::ints_in_range] | ints_in_range | ✅ Ready | Only supports safe integer range | | [nois::pick] | pick | ✅ Ready | | | [nois::select_from_weighted] | select_from_weighted | ✅ Ready | | | [nois::random_decimal] | random_decimal | ✅ Ready | Encodes result Decimal as string | | [nois::sub_randomness] | sub_randomness | ✅ Ready | Takes a count argument and returns an Array instead of an iterator | | [nois::shuffle] | shuffle | ✅ Ready | |

Installation

We need this:

$ cargo install wasm-pack -f $ wasm-pack --version wasm-pack 0.10.3

For Node.js

This creates a CommonJS module that is loaded synchonously.

``` $ wasm-pack build --target nodejs -- --features js $ node

const { coinflip, rolldice, randomdecimal, subrandomness, intinrange, intsinrange, pick, selectfrom_weighted, shuffle } = require('./pkg/nois');

// Round 2497992

coinflip("c59f098f3c12b8c36ed81f5c17660c72414a1ed63467888a374af529a205c584") 'tails'

// Round 2497994

coinflip("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba") 'heads' rolldice("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba") 6 randomdecimal("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba") '0.126047856387596389' subrandomness("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba", 3) [ 'ac7b151d67cd4263520b16e450e6d1fc01750dab80b5d8b7cdc4075c99daf80a', '33622b0865f1ab35142e3e63a91c25cf89311b04b9540ca15e49413a4a114ce1', 'f08927af18d4995c28f15f07e4038407f32d966087771314b9e64b6a33a9101c' ] intinrange("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba", 5, 9) 9 intsinrange("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba", 20, 0, 1) [ 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1 ] shuffle("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba", [1, 2, 3, "a", "b", true]) [ 2, 'a', 1, 'b', 3, true ] pick("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba", 4, [1, 2, 3, "a", "b", true]) [ 'a', 'b', 3, true ] selectfrom_weighted("2267ba7356c01a58e405d4194a31bddc3fd3eb1f0a86758f7a609ba8a47420ba", [["red", 20], ["blue", 70]]) 'blue' ```

For browsers and other JS environments

You need to change the target in order to get a suiteable package. E.g.

$ wasm-pack build --target web -- --features js $ ls ./pkg

for browsers. Please refer to the wasm-bindgen handbook to learn more about targets.