Hyperledger Fabric实践：供应链金融案例

背景描述：

在供应链金融产品中，供应商、核心企业、银行、金融机构等多方并存,共同参与交易完成。由于参与方众多，其中涉及很多清算和结算功能，如果采用传统方案解决会产生很多中间环节，导致效率低下。区块链的出现给供应链金融的实现提供了新的解决方案。

案例描述：

案例实现的是简单的“应收账款融资”场景。

业务流程：

1、核心企业与供应商线下签订合同并发货
2、供应商在链上发起供货交易
3、核心企业和金融机构确认并签名交易
4、金融机构发起放款请求给供应商
以上每一笔交易都需要所有参与方认同。

环境配置

演示为三个组织——核心企业、供应商、金融机构。
使用环境为fabric v1.1

IP	节点	域名	组织名称
10.254.186.164	orderer	orderer.gyl.com	排序节点
10.254.186.164	peer	peer0.org1.gyl.com	供应商
10.254.247.165	peer	peer0.org2.gyl.com	金融机构
10.254.207.154	peer	peer0.org3.gyl.com	核心企业

合约部分

package main

import (
    "fmt"

    "github.com/hyperledger/fabric/core/chaincode/shim"
    pb "github.com/hyperledger/fabric/protos/peer"
    "time"
    "encoding/json"
)

var asset_time = "asset_name_a"
type scfinancechaincode struct {}

/**
    系统初始化
 */

// Init callback representing the invocation of a chaincode
func (t *scfinancechaincode) Init(stub shim.ChaincodeStubInterface) pb.Response {
    fmt.Println("Init success! ")
    return shim.Success([]byte("Init success !!!!!"))
}

/**
系统Invoke方法
 */

func (t *scfinancechaincode) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
    _, args := stub.GetFunctionAndParameters()
    var opttype = args[0] //操作
    var assetname = args[1] //货物名
    var optcontent = args[2] //内容

    fmt.Printf("param is %s %s %s \n",opttype,assetname,optcontent)

    if opttype == "putvalue" { //设置
        stub.PutState(assetname,[]byte(optcontent))
        return shim.Success([]byte("success put " + optcontent))
    }else if opttype == "getlastvalue" { //取值
        var keyvalue []byte
        var err error
        keyvalue,err = stub.GetState(assetname)
        if err != nil {
            return shim.Error("find error!")
        }
        return shim.Success(keyvalue)
    }else if opttype == "gethistory" { //获取交易记录
        keyIter, err := stub.GetHistoryForKey(assetname)
        if err != nil {
            return shim.Error(fmt.Sprintf("GetHistoryForKey failed. Error accessing state: %s", err.Error()))
        }
        defer keyIter.Close()
        var keys []string //存储所有的交易ID
        for keyIter.HasNext() {
            response, iterErr := keyIter.Next()
            if iterErr != nil {
                return shim.Error(fmt.Sprintf("GetHistoryForKey operation failed. Error accessing state: %s", iterErr.Error()))
            }
            //交易编号
            txid := response.TxId
            //交易的值
            txvalue := response.Value
            //当前交易状态
            txstatus := response.IsDelete
            //交易发生的时间戳
            txtimestamp := response.Timestamp
            tm := time.Unix(txtimestamp.Seconds,0)
            datestr := tm.Format("2006-01-02 03:04:05 PM")

            fmt.Printf("Tx info - txid : %s value : %s if delete: %t datetime: %s \n",txid,string(txvalue),txstatus,datestr)
            keys = append(keys,txid)
        }

        jsonKeys, err := json.Marshal(keys)
        if err != nil {
            return shim.Error(fmt.Sprintf("query operation failed. Error marshaling JSON: %s", err.Error()))
        }
        return shim.Success(jsonKeys)
    }else {
        return shim.Success([]byte("success invoke but invalid operation"))
    }

}

func main() {
    err := shim.Start(new(scfinancechaincode))
    if err != nil {
        fmt.Printf("Error starting Simple chaincode: %s", err)
    }
}

client部分

var path = require('path');
var fs = require('fs');
var util = require('util');
var hfc = require('fabric-client');
var Peer = require('fabric-client/lib/Peer.js');
var EventHub = require('fabric-client/lib/EventHub.js');
var User = require('crypto');
var FabricCAService = require('fabric-ca-client');

//var log4js = require('log4js');
//var logger = log4js.getLogger('Helper');
//logger.setLevel('DEBUG');

var tempdir = "/home/dc2-user/kongli/fabric-client-js-kvs";

let client = new hfc();
let tls_cacerts_content_orderer = fs.readFileSync('./orderer/tls/ca.crt');
let opt_orderer = {
    pem: Buffer.from(tls_cacerts_content_orderer).toString(),
    'ssl-target-name-override':'orderer.gyl.com'
};
//peer1
let tls_cacerts_content_peer1 = fs.readFileSync('./peer1/tls/ca.crt');
let opt_peer1 = {
    pem: Buffer.from(tls_cacerts_content_peer1).toString(),
    'ssl-target-name-override':'peer0.org1.gyl.com'
};
//peer2
let tls_cacerts_content_peer2 = fs.readFileSync('./peer2/tls/ca.crt');
let opt_peer2 = {
    pem: Buffer.from(tls_cacerts_content_peer2).toString(),
    'ssl-target-name-override':'peer0.org2.gyl.com'
};
//peer3
let tls_cacerts_content_peer3 = fs.readFileSync('./peer3/tls/ca.crt');
let opt_peer3 = {
    pem: Buffer.from(tls_cacerts_content_peer3).toString(),
    'ssl-target-name-override':'peer0.org3.gyl.com'
};

var channel = client.newChannel('gylchannel');
var order = client.newOrderer('grpcs://10.254.186.164:7050',opt_orderer);
channel.addOrderer(order);
var peer1 = client.newPeer('grpcs://10.254.186.164:7051',opt_peer1);
var peer2 = client.newPeer('grpcs://10.254.247.165:7051',opt_peer2);
var peer3 = client.newPeer('grpcs://10.254.207.154:7051',opt_peer3);
channel.addPeer(peer1);
channel.addPeer(peer2);
channel.addPeer(peer3);

var event_url = 'grpcs://10.254.186.164:7053';
/**
    发起交易
    @returns {Promis.<TResult>}
*/
var sendTransaction = function(chaincodeid, func, chaincode_args, channelId) {
    var tx_id = null;
    return getOrgUser4Local().then((user)=>{
        tx_id = client.newTransactionID();
        var request = {
            chaincodeId: chaincodeid,
            fcn: func,
            args: chaincode_args,
            chainId: channelId,
            txId: tx_id
        };
        return channel.sendTransactionProposal(request);
    },(err)=>{
        console.log('error',err);
    }).then((chaincodeinvokresult)=>{
        var proposalResponses = chaincodeinvokresult[0];
        var proposal = chaincodeinvokresult[1];
        var header = chaincodeinvokresult[2];
        var all_good = true;
        for (var i in proposalResponses) {
            let one_good = false;
            //成功
            if (proposalResponses && proposalResponses[0].response && proposalResponses[0].response.status == 200) {
                one_good = true;
                console.info('transaction proposal was good');
            }else {
                console.error('transaction proposal was bad');
            }
            all_good = all_good & one_good;
        }

        if (all_good) {
            console.info(util.format(
                'Successfully sent proposal and received proposalResponses: Status - %s, message - "%s", metadate - "%s", endorsement signature :%s',
                proposalResponses[0].response.status,proposalResponses[0].response.message,
                proposalResponses[0].response.payload,proposalResponses[0].endorsement.signature));

            var request = {
                proposalResponses: proposalResponses,
                proposal: proposal,
                orderer: order,
                txId: tx_id,
        header:header
            };

            var transactionID = tx_id.getTransactionID();
        var eventPromises = [];
        let eh = client.newEventHub();
        //接下来设置EventHub，用于监听Transaction是否成功写入，这里也是启用了TLS
        eh.setPeerAddr(event_url,opt_peer1);
            eh.connect();
            let txPromise = new Promise((resolve, reject) => {
                let handle = setTimeout(() => {
                    eh.disconnect();
                    reject();
                }, 30000);
            //向EventHub注册事件的处理办法
                eh.registerTxEvent(transactionID, (tx, code) => {
                    clearTimeout(handle);
                    eh.unregisterTxEvent(transactionID);
                    eh.disconnect();

                    if (code !== 'VALID') {
                            console.error(
                            'The transaction was invalid, code = ' + code);
                            reject();
                    } else {
                            console.log(
                            'The transaction has been committed on peer ' +
                            eh._ep._endpoint.addr);
                            resolve();
                    }
                });
            });
            eventPromises.push(txPromise);
            //把背书后的结果发到orderer排序
            var sendPromise = channel.sendTransaction(request);
        return Promise.all([sendPromise].concat(eventPromises)).then((results) => {
                console.log(' event promise all complete and testing complete');
                return results[0]; // the first returned value is from the 'sendPromise' which is from the 'sendTransaction()' call
            }).catch((err) => {
                console.error(
                    'Failed to send transaction and get notifications within the timeout period.'
                );
                return 'Failed to send transaction and get notifications within the timeout period.';
           });
         } else {
             console.error(
                'Failed to send Proposal or receive valid response. Response null or status is not 200. exiting...'
             );
            return 'Failed to send Proposal or receive valid response. Response null or status is not 200. exiting...';
        }
    },(err)=>{
        console.log('error',err);
    }).then((response)=>{
    if (response.status === 'SUCCESS') {
            console.log('Successfully sent transaction to the orderer.');
            return tx_id.getTransactionID();
        } else {
            console.error('Failed to order the transaction. Error code: ' + response.status);
            return 'Failed to order the transaction. Error code: ' + response.status;
        }
    },(err)=>{
        console.log('error',err);
    });
}


/**
    根据cryptogen模块生成的账号通过Fabric接口进行相关操作
    @returns {Promise.<TResult>}
*/
function getOrgUser4Local(){
    var keyPath = "./users/keystore";
    var keyPEM = Buffer.from(readAllFiles(keyPath)[0]).toString();
    var certPath = "./users/signcerts";
    var certPEM = readAllFiles(certPath)[0].toString();

    return hfc.newDefaultKeyValueStore({
        path: tempdir
    }).then((store)=>{
        client.setStateStore(store);

        return client.createUser({
            username: 'user87',
            mspid: 'GylOrg1MSP',
            cryptoContent: {
                privateKeyPEM: keyPEM,
                signedCertPEM: certPEM
            }
        });
    });
};

function readAllFiles(dir) {
    var files = fs.readdirSync(dir);
    var certs = [];
    files.forEach((file_name)=>{
        let file_path = path.join(dir,file_name);
        let data = fs.readFileSync(file_path);
        certs.push(data);
    });
    return certs;
}

/**
    获取channel的区块信息
    @returns {Promise.<TResult>}
*/
var getBlockChainInfo = function() {
    return getOrgUser4Local().then((user)=>{
        return channel.queryInfo(peer1);
    },(err)=>{
        console.log('error',err);
    })
}

/**
    根据区块链的编号获取详细信息
    @param blocknum
    @returns {Promise.<TResult>}
*/
var getblockInfobyNum = function(blocknum) {
    return getOrgUser4Local().then((user)=>{
        return channel.queryBlock(blocknum,peer1,null);
    },(err)=>{
        console.log('error',err);
    })
}

/**
    根据区块链的哈希值获取区块详细信息
    @param blockhash
    @returns {Promise.<TResult>}
*/
var getblockInfobyHash = function(blockHash) {
    return getOrgUser4Local().then((user)=>{
        return channel.queryBlockByHash(new Buffer(blockHash,"hex"),peer1);
    },(err)=>{
        console.log('error',err);
    })
}
/**
    获取当前节点加入的通道信息
    @returns {Promise.<TResult>}
*/
var getPeerChannel = function() {
    return getOrgUser4Local().then((user)=>{
        return client.queryChannels(peer1);
    },(err)=>{
        console.log('error',err);
    })
}

/**
    查询指定peer节点已经install的chaincode
    @returns {Promise.<TResult>}
*/
var getPeerInstallCc = function() {
    return getOrgUser4Local().then((user)=>{
        return client.queryInstalledChaincodes(peer1);
    },(err)=>{
        console.log('error',err);
    })
}

/**
    查询指定channel中已实例化的chaincode
    @returns {Promise.<TResult>}
*/
var getPeerInstantiatedCc = function() {
    return getOrgUser4Local().then((user)=>{
        return channel.queryInstantiatedChaincodes(peer1);
    },(err)=>{
        console.log('error',err);
    })
}

/**
    查询指定交易所在区块信息
    @param txId
    @returns {Promis.<TResult>}
 */
var getBlockByTxID = function(TxID) {
    return getOrgUser4Local().then((user)=>{
        return channel.queryBlockByTxID(TxID,peer1);
    },(err)=>{
        console.log('error',err);
    })
}

/**
    查询指定交易所在区块信息
    @param txId
    @returns {Promis.<TResult>}
 */
var getTransaction = function(TxID) {
    return getOrgUser4Local().then((user)=>{
        return channel.queryTransaction(TxID,peer1);
    },(err)=>{
        console.log('error',err);
    })
}

exports.sendTransaction = sendTransaction;
exports.getBlockChainInfo = getBlockChainInfo;
exports.getblockInfobyNum = getblockInfobyNum;
exports.getblockInfobyHash = getblockInfobyHash;
exports.getPeerChannel = getPeerChannel;
exports.getPeerInstantiatedCc = getPeerInstantiatedCc;
exports.getPeerInstallCc = getPeerInstallCc;
exports.getBlockByTxID = getBlockByTxID;
exports.getTransaction = getTransaction;

浏览器部分

var co = require('co');
var fabricservice = require('./fabricservice.js');
var express = require('express');

var app = express();

var channelid = "gylchannel";
var chaincodeid = "gyl";

//供应商发起供货交易
app.get('/sendTransaction1',function(req,res){
    co(function * () {
        var k = req.query.k;
        var v = req.query.v;
        var blockinfo = yield fabricservice.sendTransaction(chaincodeid,"invoke",["putvalue",k,v],channelid);
         res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
});

//核心企业发起确认
app.get('/sendTransaction2',function(req,res){
    co(function * () {
        var k = req.query.k;
        var v = req.query.v;
        var blockinfo = yield fabricservice.sendTransaction(chaincodeid,"invoke",["putvalue",k,v],channelid);
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//金融机构审核并放款
app.get('/sendTransaction3',function(req,res){
    co(function * () {
        var k = req.query.k;
        var v = req.query.v;
        var blockinfo = yield fabricservice.sendTransaction(chaincodeid,"invoke",["putvalue",k,v],channelid);
         res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//查询交易记录
app.get('/queryhistory',function(req,res){
    co(function * () {
        var k = req.query.k;
        var blockinfo = yield fabricservice.sendTransaction(chaincodeid,"invoke",["gethistory",k,"-1"],channelid);
         res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})


//查询最新结果
app.get('/getlastvalue',function(req,res){
    co(function * () {
        var k = req.query.k;
        var blockinfo = yield fabricservice.sendTransaction(chaincodeid,"invoke",["getlastvalue",k,"-1"],channelid);
         res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})


//获取当前通道块儿高度
app.get('/getchannelheight',function(req,res){
    co(function * () {
        var blockinfo = yield fabricservice.getBlockChainInfo();
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//根据区块编号获取区块信息
app.get('/getblockInfobyNum',function(req,res){
    co(function * () {
        var param = parseInt(req.query.params);
        var blockinfo = yield fabricservice.getblockInfobyNum(param);
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//根据区块Hash值获取区块信息
app.get('/getblockInfobyHash',function(req,res){
    co(function * () {
        var param = req.query.params;
        var blockinfo = yield fabricservice.getblockInfobyHash(param);
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//获取指定peer节点加入的通道数
app.get('/getPeerChannel',function(req,res){
    co(function * () {
        var blockinfo = yield fabricservice.getPeerChannel();
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})


//获取channel已经安装的链码
app.get('/getPeerInstallCc',function(req,res){
    co(function * () {
        var blockinfo = yield fabricservice.getPeerInstallCc();
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})


//获取指定channel已经实例化的链码
app.get('/getPeerInstantiatedCc',function(req,res){
    co(function * () {
        var blockinfo = yield fabricservice.getPeerInstantiatedCc();
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//通过交易ID获取区块信息
app.get('/getBlockByTxID',function(req,res){
    co(function * () {
        var param = req.query.TxID;
        var blockinfo = yield fabricservice.getBlockByTxID(param);
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//通过交易ID获取交易信息
app.get('/getTransaction',function(req,res){
    co(function * () {
        var param = req.query.TxID;
        var blockinfo = yield fabricservice.getTransaction(param);
        res.send(JSON.stringify(blockinfo));
    }).catch((err)=>{
        res.send(err);
    })
})

//启动http服务
var server = app.listen(3000,function(){
    var host = server.address().address;
    var port = server.address().port;
    console.log('Example app listen at http://%s:%s',host,port);
});

//注册异常处理器
process.on('unhandleRejection',function(err){
    console.error(err.stack);
});

process.on('uncaughtException',console.error);

流程

1、供应商发起供货交易调用，如：
http://116.85.10.181:3000/sendTransaction1?k=food&v=1
2、核心企业发起确认，如：
http://116.85.10.181:3000/sendTransaction2?k=food&v=2
3、银行审核后确认放款，如：
http://116.85.10.181:3000/sendTransaction3?k=food&v=3

目前链码写的比较简单，最好每个组织有自己的链码，组织间约定好操作内容。即使采用同样的链码，由于账本中会记录调用者的身份信息（组织以及签名等），所以假如供应商直接调用http://116.85.10.181:3000/sendTransaction3?k=food&v=3 虽然通过但是账本会记录调用者不是银行机构，可以认定无效。

注意：

1、需要准备npm环境，fabric-client 需要在v.1.10 grpc为v.1.10.1
可以使用npm list xxx 来查看版本信息。
2、使用浏览器访问需要开通端口访问权限。