I created simple smart contract that generates game character with random attributes and pushes it to an array.
Function requestNewRandomCharacter() does three things:
- Changes characterNameForMinting storage variable value to: [parameter: name] + "_before";
- Calls Chainlink VRF requestRandomness();
- Changes characterNameForMinting storage variable value to: [parameter: name] + "_after";
Function fulfillRandomness() is called inside requestRandomness() function and it pushes element to an array. But element name already has "_after" suffix. Why is that? At the moment function is called characterNameForMinting storage variable value has "_before" suffix.
Full contract code:
pragma solidity ^0.8; import "@chainlink/contracts/src/v0.8/VRFConsumerBase.sol"; contract RandomNumberConsumer is VRFConsumerBase { bytes32 internal keyHash; uint256 internal fee; string public characterNameForMinting; struct Character { uint256 strength; uint256 dexterity; uint256 constitution; uint256 intelligence; uint256 wisdom; uint256 charisma; uint256 experience; string name; } Character[] public characters; /** * Constructor inherits VRFConsumerBase * * Network: Rinkeby * Chainlink VRF Coordinator address: 0xb3dCcb4Cf7a26f6cf6B120Cf5A73875B7BBc655B * LINK token address: 0x01BE23585060835E02B77ef475b0Cc51aA1e0709 * Key Hash: 0x2ed0feb3e7fd2022120aa84fab1945545a9f2ffc9076fd6156fa96eaff4c1311 */ constructor() VRFConsumerBase( 0xb3dCcb4Cf7a26f6cf6B120Cf5A73875B7BBc655B, // VRF Coordinator 0x01BE23585060835E02B77ef475b0Cc51aA1e0709 // LINK Token ) { keyHash = 0x2ed0feb3e7fd2022120aa84fab1945545a9f2ffc9076fd6156fa96eaff4c1311; fee = 0.1 * 10 ** 18; // 0.1 LINK (Varies by network) } function requestNewRandomCharacter( string memory name ) public returns (bytes32) { require( LINK.balanceOf(address(this)) >= fee, "Not enough LINK - fill contract with faucet" ); characterNameForMinting = string(abi.encodePacked(name, "_before")); bytes32 requestId = requestRandomness(keyHash, fee); characterNameForMinting = string(abi.encodePacked(name, "_after")); return requestId; } function fulfillRandomness(bytes32 requestId, uint256 randomNumber) internal override { uint256 strength = (randomNumber % 100); uint256 dexterity = ((randomNumber % 10000) / 100 ); uint256 constitution = ((randomNumber % 1000000) / 10000 ); uint256 intelligence = ((randomNumber % 100000000) / 1000000 ); uint256 wisdom = ((randomNumber % 10000000000) / 100000000 ); uint256 charisma = ((randomNumber % 1000000000000) / 10000000000); uint256 experience = 0; characters.push( Character( strength, dexterity, constitution, intelligence, wisdom, charisma, experience, characterNameForMinting ) ); } }
