Example - Advanced Request

The AdvancedGetShuffledArrayExample shows how to request and consume randomness of type Shuffling without extending GeneralRandcastConsumerBase.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {BasicRandcastConsumerBase} from "randcast-user-contract/user/BasicRandcastConsumerBase.sol";
import {RequestIdBase} from "randcast-user-contract/utils/RequestIdBase.sol";
// solhint-disable-next-line no-global-import
import "randcast-user-contract/user/RandcastSDK.sol" as RandcastSDK;

contract AdvancedGetShuffledArrayExample is RequestIdBase, BasicRandcastConsumerBase, RandomnessHandler {
    mapping(bytes32 => uint256) public shuffledArrayUppers;
    uint256[][] public shuffleResults;

    // solhint-disable-next-line no-empty-blocks
    constructor(address adapter) BasicRandcastConsumerBase(adapter) {}

     * Requests randomness
    function getRandomNumberThenGenerateShuffledArray(
        uint256 shuffledArrayUpper,
        uint64 subId,
        uint256 seed,
        uint16 requestConfirmations,
        uint32 callbackGasLimit,
        uint256 callbackMaxGasPrice
    ) external returns (bytes32) {
        bytes memory params;

        uint256 rawSeed = _makeRandcastInputSeed(seed, address(this), nonce);
        // This should be identical to controller generated requestId.
        bytes32 requestId = _makeRequestId(rawSeed);
        shuffledArrayUppers[requestId] = shuffledArrayUpper;

        return _rawRequestRandomness(
            RequestType.Randomness, params, subId, seed, requestConfirmations, callbackGasLimit, callbackMaxGasPrice

        // These equals to following code(recommended):
        // bytes32 requestId = rawRequestRandomness(
        //    RequestType.Randomness,
        //    params,
        //    subId,
        //    seed,
        //    requestConfirmations,
        //    callbackGasLimit,
        //    callbackMaxGasPrice
        // );

        // shuffledArrayUppers[requestId] = shuffledArrayUpper;

     * Callback function used by Randcast Adapter
    function _fulfillRandomness(bytes32 requestId, uint256 randomness) internal override {
        shuffleResults.push(RandcastSDK.shuffle(shuffledArrayUppers[requestId], randomness));

    function lengthOfShuffleResults() public view returns (uint256) {
        return shuffleResults.length;

In getRandomNumberThenGenerateShuffledArray function, before requesting randomness, you can have more flexibility. For example, you can pass the user seed as input parameter, and calculate the raw seed and request id of the next randomness request before actually calling the _rawRequestRandomness function.

Also, you can set subId, requestConfirmations, callbackGasLimit, and callbackMaxGasPrice specifically for each randomness request.

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