《Solidity 简易速速上手小册》第10章：区块链项目实战（2024 最新版）（下）

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract Identity {
    struct UserInfo {
        uint256 id;
        string name;
        bool verified;
    }
    mapping(address => UserInfo) public users;
    function register(string memory _name) public {
        users[msg.sender] = UserInfo(users.length, _name, false);
    }
    function verifyUser(address _user) public {
        // 验证用户逻辑，通常由可信第三方执行...
        users[_user].verified = true;
    }
    // 其他必要的功能...
}

// 使用React或Vue.js
import Web3 from 'web3';
import IdentityContract from './Identity.json';
const web3 = new Web3(Web3.givenProvider);
const identityAddress = '合约地址';
const identity = new web3.eth.Contract(IdentityContract.abi, identityAddress);
const registerUser = async (name) => {
    const accounts = await web3.eth.getAccounts();
    identity.methods.register(name).send({ from: accounts[0] });
};
const verifyUser = async (userAddress) => {
    const accounts = await web3.eth.getAccounts();
    identity.methods.verifyUser(userAddress).send({ from: accounts[0] });
};
// 前端界面逻辑...

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract CrossChainBridge {
    mapping(address => uint256) public balances;
    function deposit() public payable {
        balances[msg.sender] += msg.value;
    }
    function initiateTransfer(address _to, uint256 _amount, address _destinationChain) public {
        require(balances[msg.sender] >= _amount, "Insufficient balance");
        balances[msg.sender] -= _amount;
        // 发起跨链转移逻辑...
    }
    // 其他必要的功能...
}

// 使用React或Vue.js
import Web3 from 'web3';
import CrossChainBridgeContract from './CrossChainBridge.json';
const web3 = new Web3(Web3.givenProvider);
const bridgeAddress = '合约地址';
const bridge = new web3.eth.Contract(CrossChainBridgeContract.abi, bridgeAddress);
const depositFunds = async (amount) => {
    const accounts = await web3.eth.getAccounts();
    bridge.methods.deposit().send({ from: accounts[0], value: amount });
};
const initiateTransfer = async (to, amount, destinationChain) => {
    const accounts = await web3.eth.getAccounts();
    bridge.methods.initiateTransfer(to, amount, destinationChain).send({ from: accounts[0] });
};
// 前端界面逻辑...

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract DAOSmartContract {
    struct Proposal {
        uint256 id;
        string description;
        uint256 voteCount;
    }
    mapping(address => bool) public members;
    Proposal[] public proposals;
    function joinDAO() public {
        members[msg.sender] = true;
    }
    function createProposal(string memory _description) public {
        require(members[msg.sender], "Only members can create proposals");
        proposals.push(Proposal(proposals.length, _description, 0));
    }
    function voteOnProposal(uint256 _proposalId) public {
        require(members[msg.sender], "Only members can vote");
        proposals[_proposalId].voteCount += 1;
    }
    // 其他必要的功能...
}

// 使用React或Vue.js
import Web3 from 'web3';
import DAOSmartContract from './DAOSmartContract.json';
const web3 = new Web3(Web3.givenProvider);
const daoAddress = '合约地址';
const dao = new web3.eth.Contract(DAOSmartContract.abi, daoAddress);
const joinDAO = async () => {
    const accounts = await web3.eth.getAccounts();
    dao.methods.joinDAO().send({ from: accounts[0] });
};
const createProposal = async (description) => {
    const accounts = await web3.eth.getAccounts();
    dao.methods.createProposal(description).send({ from: accounts[0] });
};
const voteOnProposal = async (proposalId) => {
    const accounts = await web3.eth.getAccounts();
    dao.methods.voteOnProposal(proposalId).send({ from: accounts[0] });
};
// 前端界面逻辑...

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract SmartCity {
    struct Citizen {
        uint256 id;
        string name;
        bool hasVotingRight;
    }
    mapping(address => Citizen) public citizens;
    mapping(uint256 => string) public cityData;
    function registerCitizen(address _citizenAddress, string memory _name) public {
        citizens[_citizenAddress] = Citizen(citizens.length, _name, true);
    }
    function updateCityData(uint256 _dataId, string memory _data) public {
        cityData[_dataId] = _data;
        // 数据更新逻辑...
    }
    // 其他必要的功能...
}

// 使用React或Vue.js
import Web3 from 'web3';
import SmartCityContract from './SmartCity.json';
const web3 = new Web3(Web3.givenProvider);
const smartCityAddress = '合约地址';
const smartCity = new web3.eth.Contract(SmartCityContract.abi, smartCityAddress);
const registerCitizen = async (citizenAddress, name) => {
    const accounts = await web3.eth.getAccounts();
    smartCity.methods.registerCitizen(citizenAddress, name).send({ from: accounts[0] });
};
const updateCityData = async (dataId, data) => {
    const accounts = await web3.eth.getAccounts();
    smartCity.methods.updateCityData(dataId, data).send({ from: accounts[0] });
};
// 前端界面逻辑...