金融供应链智能合约 — 智能合约实例

前提

Ownable:监管者合约,有一个函数能转让监管者。

SupplyChainFin:供应链金融合约,银行、公司信息上链，公司和银行之间的转账。

发票：记录者交易双方和交易金额等的一种记录数据。如:我在超市买了一瓶水,超市给我开了一张发票。

Ownable

// SPDX-License-Identifier: MITpragma solidity >=0.4 <=0.9;/**@title Ownable*@dev */contract Ownable{address public owner; // 监管者event OwnershipTransferred( // 监管者转让结构体address indexed priviousOwner, // indexed表名可以被索引address indexed newOwner);constructor() {owner = msg.sender;}// 判断用户是否是监管者modifier onlyOwner(){require(msg.sender == owner,"You cannot owner!");_;}// 转让所有权,必须是原先监管者转让function transferOwnership(address newOwner) public onlyOwner{require(newOwner != owner && newOwner != address(0),"newOwner cannot be empty and equal to the priviousOwner");emit OwnershipTransferred(owner, newOwner);owner = newOwner;}}

SupplyChainFin

// SPDX-License-Identifier: MITpragma solidity >=0.4  Company) companyMap;// 银行mapmapping (address =>Bank) bankMap;// 发票的mapmapping (uint => Receipt) receiptMap;//监管者实体Supervisor public supervisor;// 公司地址的数组address[] public companies;// 银行地址的数组address[] public banks;//数组发票索引uint public receiptIndex;constructor(string memory name){supervisor = Supervisor(name,msg.sender); // 初始化监管者信息}// 将公司信息添加到智能合约中function addCompany(string memory name,address companyAddress)public payablereturns(bool){// 初始化公司结构体// 添加到公司map// 添加到公司数组Company memory newCompany = Company(name,companyAddress,msg.value,new uint[](0),new uint[](0));companyMap[companyAddress] = newCompany;companies.push(companyAddress);return true;}// 获取公司信息function getCompany(address companyAddress) public viewreturns(string memory,address,uint,uint[] memory,uint[] memory){// 用地址拿出公司结构体// 将需要的数据一起返回Company memory company = companyMap[companyAddress];return (company.companyName,company.companyAddress,company.creditAsset,company.acceptReceiptIndex,company.sendReceiptIndex);}// 添加银行信息上链function addBank(string memory bankName,address bankAddress) public payablereturns(bool){Bank memory newBank;newBank.bankName = bankName;newBank.bankAddress = bankAddress;newBank.creditAsset = msg.value;bankMap[bankAddress] = newBank;banks.push(bankAddress);return true;}// 获取银行信息function getBank(address bankAddress) public viewreturns(string memory,address,uint,uint[] memory,uint[] memory){Bank memory bank = bankMap[bankAddress];return (bank.bankName,bank.bankAddress,bank.creditAsset,bank.acceptReceiptIndex,bank.sendReceiptIndex);}// 获取公司全部地址function getAllCompanyAddress() public view returns(address[] memory){return companies;}// 获取银行全部地址function getAllBankAddress() public view returns(address[] memory){return banks;}// 获取凭证function getRecipt(uint index)public view returns(address,address,uint8,uint8,uint){Receipt memory receipt = receiptMap[index];return (receipt.senderAddress,receipt.accepterAddress,receipt.receiptType,receipt.transferType,receipt.amount);}//存证交易// receiptType: 发票类型(存证、现金)//1: 交易类型为存证//2：交易类型为现金// transferType: 交易类型//1: 银行转账给公司//2: 公司与公司间转账//3: 公司转账给银行// 银行向公司交易(公司颁布凭证):function bankToCompanyReceipt(address senderAddress, // 凭证发送方address accepterAddress, // 凭证接受方uint amount, // 交易额uint8 receiptType // 凭证类型) public returns(uint){// 银行转账给公司,银行是发票接受者，只有银行同意要发票，这笔交易才能执行require(msg.sender == accepterAddress,"The function caller must be accper");// 拿出银行、公司结构体Company memory company = companyMap[senderAddress];Bank memory bank = bankMap[accepterAddress];// 判断公司银行是否存在if(keccak256(bytes(bank.bankName)) == keccak256(bytes(""))){return 404001;}if(keccak256(bytes(company.companyName)) == keccak256(bytes(""))){return 404002;}// 判断银行资产是否小于转账额if(bank.creditAsset < amount){return 500001;}// 初始化凭证Receipt memory newReceipt = Receipt(senderAddress,accepterAddress,receiptType,1,amount);// 发票索引 + 1receiptIndex += 1;// 根据转账额,相互的 +-companyMap[accepterAddress].creditAsset += amount;bankMap[senderAddress].creditAsset -= amount;// 存凭证索引,这样我们拿到公司或银行信息,拿到发票索引,在拿到发票结构体receiptMap[receiptIndex] = newReceipt;companyMap[accepterAddress].sendReceiptIndex.push(receiptIndex);bankMap[senderAddress].acceptReceiptIndex.push(receiptIndex);return 200;}//公司向公司交易(接受钱的公司需要颁布凭证)function companyToCompanyReceipt(address senderAddress,address accepterAddress,uint amount,uint8 receiptType) publicreturns(uint){require(msg.sender == accepterAddress);Company memory senderCompany = companyMap[senderAddress];Company memory accepterCompany = companyMap[accepterAddress];if (keccak256(bytes(senderCompany.companyName)) == keccak256(bytes(""))) {return 404001;}//确认接收公司存在if (keccak256(bytes(accepterCompany.companyName)) == keccak256(bytes(""))) {return 404002;}//如果存证接收的公司资产小于存证数额，那么就不能交易发送存证if (accepterCompany.creditAsset < amount) {return 500001;}//创建存证Receipt memory newReceipt = Receipt(senderAddress,accepterAddress,receiptType,2,amount);receiptIndex += 1;//记录存证（存证Map，公司Map对应地址的发送和接收存证列表）receiptMap[receiptIndex] = newReceipt;companyMap[senderAddress].sendReceiptIndex.push(receiptIndex);companyMap[accepterAddress].acceptReceiptIndex.push(receiptIndex);companyMap[senderAddress].creditAsset += amount;companyMap[accepterAddress].creditAsset -= amount;return 200;}//公司与银行交易(银行颁布凭证)function companyToBankReceipt(address senderAddress,address accepterAddress,uint amount,uint8 receiptType) publicreturns (uint) { require(msg.sender == accepterAddress);Bank memory bank = bankMap[senderAddress];Company memory accepterCompany = companyMap[accepterAddress];//确认发送公司存在if (keccak256(bytes(bank.bankName)) == keccak256(bytes(""))) {return 404001;}//确认接收公司存在if (keccak256(bytes(accepterCompany.companyName)) == keccak256(bytes(""))) {return 404002;} //如果存证接收的公司资产小于存证数额，那么就不能交易发送存证if (accepterCompany.creditAsset < amount) {return 500001;}//创建存证Receipt memory newReceipt = Receipt(senderAddress,accepterAddress,receiptType,3,amount);receiptIndex += 1;//记录存证（存证Map，公司Map对应地址的发送和接收存证列表）receiptMap[receiptIndex] = newReceipt;bankMap[senderAddress].sendReceiptIndex.push(receiptIndex);companyMap[accepterAddress].acceptReceiptIndex.push(receiptIndex);bankMap[senderAddress].creditAsset += amount;companyMap[accepterAddress].creditAsset -= amount;return 200;}}