本文是在閱讀《區(qū)塊鏈開(kāi)發(fā)實(shí)戰(zhàn)-Hyperledger Fabric關(guān)鍵技術(shù)與案例分析》一書(shū)的同時(shí)皿伺，在實(shí)踐中記錄的一些實(shí)踐步驟與經(jīng)驗(yàn)分享。

Hyperledger Fabric開(kāi)發(fā)實(shí)戰(zhàn)-07 開(kāi)發(fā)流程

Fabric的Orderer節(jié)點(diǎn)和Peer節(jié)點(diǎn)都提供了基于Grpc協(xié)議的接口，通過(guò)這些接口可以和這些節(jié)點(diǎn)進(jìn)行交互举庶，但是如果直接使用這些接口，需要自己定義很多protobuf協(xié)議的文件，為了簡(jiǎn)化開(kāi)發(fā)琳轿，F(xiàn)abric提供了Node.js,Go,Java等語(yǔ)言的相關(guān)SDK，方便用戶與相關(guān)節(jié)點(diǎn)進(jìn)行交互耿芹。在項(xiàng)目的開(kāi)發(fā)中崭篡，我們大都通過(guò)調(diào)用Peer模塊的Grpc接口，與系統(tǒng)進(jìn)行交互吧秕。

Fabric Node.js SDK是目前相對(duì)比較完善且成熟的SDK琉闪，因此以Node.js為例進(jìn)行學(xué)## 習(xí)。

環(huán)境準(zhǔn)備

由于需要使用到Node.js砸彬，需要先安裝颠毙，由于我的8.11.1版本在安裝依賴(lài)時(shí)一直報(bào)錯(cuò)斯入，之后重新安裝了8.9.3版本，才能正常使用

wget https://nodejs.org/dist/v8.9.3/node-v8.9.3-linux-x64.tar.xz
tar -xvf node-v8.9.3-linux-x64.tar.xz
sudo mv node-v8.9.3-linux-x64 /usr/local
sudo ln -s /usr/local/node-v8.9.3-linux-x64/bin/node /usr/local/bin/node 
sudo ln -s /usr/local/node-v8.9.3-linux-x64/bin/npm /usr/local/bin/npm 

驗(yàn)證版本

node -v
npm -v

編寫(xiě)Node.js時(shí)蛀蜜，為了調(diào)試方便刻两，推薦使用Visual Studio Code。

編寫(xiě)程序

1.安裝依賴(lài)

首先創(chuàng)建一個(gè)目錄sdkstudy涵防，用來(lái)存放需要源代碼闹伪，之后在里面創(chuàng)建package.json文件，

{
    "name": "fabric-sdk-node-study",
    "version": "0.0.1",
    "description": "fabric-sdk-node-study",
    "main": "main.js",
    "keywords": [],
    "engines": {
        "node": ">=8.0.0",
        "npm": ">=3.10.10"
    },
    "dependencies": {
        "fabric-ca-client": "^1.0.0",
        "fabric-client": "^1.0.0"
    },
    "license": "Apache-2.0"
}

dependencies里面是我們需要使用到的sdk壮池，在sdkstudy中輸入npm install命令安裝偏瓤。如果出現(xiàn)錯(cuò)誤，請(qǐng)嘗試使用sudo npm install --unsafe-perm

2.編寫(xiě)代碼

在使用sdk時(shí)椰憋，我們首先要?jiǎng)?chuàng)建client對(duì)象厅克，并指定Orderer，Peer和Channel橙依，之后通過(guò)本地證書(shū)或caserver獲取證書(shū)证舟，最后再與Peer進(jìn)行交互。

// import 
var co = require("co")
var path = require("path")
var fs = require("fs")
var util = require("util")
var hfclient = require("fabric-client")
var Peer = require("fabric-client/lib/Peer.js");
var EventHub = require("fabric-client/lib/ChannelEventHub");
var User = require("fabric-client/lib/User.js");
var crypto = require("crypto")
var FabricCAService = require("fabric-ca-client")

// 證書(shū)文件的緩存目錄
var tempdir = "/home/shisj/mycode/github_wksp/fabric/nodejs-client/client-study/kvs";

// fabric client agent
var client = new hfclient();
var cryptoSuite = hfclient.newCryptoSuite()
cryptoSuite.setCryptoKeyStore(hfclient.newCryptoKeyStore({path:tempdir}))
client.setCryptoSuite(cryptoSuite);
const ORDERER_IP = "xxx.xx.xxx.xxx";
const PEER_IP = "xx.xxx.xx.xxx";
// 創(chuàng)建CA客戶端 
var channel = client.newChannel("cmbcchannel666");
var order = client.newOrderer("grpc://" + ORDERER_IP + ":7050");
channel.addOrderer(order);

var peer = client.newPeer("grpc://"+PEER_IP+":7051");
channel.addPeer(peer);

使用本地證書(shū)

使用本地證書(shū)的時(shí)候窗骑，首先需要獲取Org1組織的Admin的證書(shū)和私鑰女责，再創(chuàng)建用戶

function readAllFiles(dirPath){
    var files = fs.readdirSync(dirPath);  
    var data = fs.readFileSync(path.join(dirPath,files[0]), 'utf8');
    return data;
}

/**
 * 根據(jù)cryptogen模塊生成的帳號(hào)通過(guò)Fabric接口進(jìn)行相關(guān)的操作
 */
function getOrgUser4Local(){
    var keyPath = "/home/shisj/mycode/github_wksp/fabric/nodejs-client/client-study/fabric-config/msp/keystore";
    var keyPEM = Buffer.from(readAllFiles(keyPath)).toString()
    var certPath = "/home/shisj/mycode/github_wksp/fabric/nodejs-client/client-study/fabric-config/msp/signcerts";
    var certPEM = readAllFiles(certPath).toString()

    return hfclient.newDefaultKeyValueStore({path:tempdir})
    .then((store) =>{
        client.setStateStore(store);
        return client.createUser({
            username:"user87",
            mspid:"Org1MSP",
            cryptoContent:{
                privateKeyPEM:keyPEM,
                signedCertPEM:certPEM
            }
        })
    })
    
}

最后，就可以連接到Peer查看賬本的相關(guān)信息了

co((function *(){
    let member = yield getOrgUser4Local()
    let resultPeerInfo = yield channel.queryInfo(peer)
    console.info("============當(dāng)前peer加入的某個(gè)channel的區(qū)塊數(shù)============");
    console.info(JSON.stringify(resultPeerInfo))

    console.info("============當(dāng)前peer加入了那些channel============");
    var result = yield client.queryChannels(peer)
    console.info(JSON.stringify(result))

    //console.info("============當(dāng)前peer加入的某個(gè)channel的區(qū)塊數(shù)的區(qū)塊號(hào)============");
    //result = yield client.queryChannels(2,peer,null)
    //console.info(JSON.stringify(result))

    console.info("============當(dāng)前peer加入chaincode[install]的信息============");
    result = yield client.queryInstalledChaincodes(peer)
    var chaincodes = result.chaincodes;
    chaincodes.forEach(element => {
        console.info("chaincode name is %s, version is %s ",element.name,element.version);
    });
    // console.info(JSON.stringify(result))
})())

與Peer通信時(shí)创译，還可以調(diào)用Chaincode

   let tx_id = client.newTransactionID();
   var request = {
       targets: peer,
       chaincodeId:"statechaincode",
       fcn:"invoke",
       args:["a","b","1"],
       chainId:"cmbcchannel666",
       txId:tx_id
   };
  // 
   let chaincodeInvokeResult = yield channel.sendTransactionProposal(request);