Hyperledger Fabric 1.0 实战开发系列第四课搭建node.js服务器

接下来我要做的是用fabric sdk来做出应用程序，代替CLI与整个区块链网络交互。并且实现一个http API，向社区提供一个简单的接口，使社区轻松的与区块链交互。

官方虽然提供了Node.JS，Java，Go（最近刚出了python）等多种语言的SDK，但是很多SDK还不成熟和完善，有的甚至文档都没有。我使用Node.js的原因有二。1.官方例子使用的是Node.js SDK 2.因为Node.js实现一个http服务器是非常简单的。

我们可以选择将node.js安装在本地，或者将node应用部署在docker。需要注意的是fabric目前不支持node7.x版本，需要6.9.x或更高版本和NPM。

一、下载nodejs

1.下载node.js，由于node服务器在国外所以需要翻墙下载，在Terminal中输入以下命令：

wget https://nodejs.org/download/release/v6.10.0/node-v6.10.0-linux-x64.tar.gz

2、下载下来的tar文件上传到服务器并且解压，然后通过建立软连接变为全局；

1）上传服务器可以是自己任意路径，目前我的放置路径为 /usr/local

2）解压上传（解压后的文件我这边将名字改为了nodejs，这个地方自己随意，只要在建立软连接的时候写正确就可以）

① tar -xvf node-v6.10.0-linux-x64.tar.xz

② mv node-v6.10.0-linux-x64 nodejs

③确认一下nodejs下bin目录是否有node 和npm文件，如果有执行软连接，如果没有重新下载执行上边步骤；

3）建立软连接，变为全局

①ln -s /usr/local/nodejs/bin/npm /usr/local/bin/

②ln -s /usr/local/nodejs/bin/node /usr/local/bin/

4）最后一步检验nodejs是否已变为全局

在Linux命令行node -v 命令会显示nodejs版本，如图所示为大功告成

二.创建node.js程序

1.编写package.json并下载依赖模块

我们首先在当前用户的根目录建立一个nodeTest的文件夹，用于存放我们关于node的相关项目文件，然后在其中新建一个包配置文件，package.json

mkdir ~/nodeTest
cd ~/nodeTest
vi package.json

在这个文件中，我们可以定义很多项目相关的属性，这篇博客详细的介绍了每个属性有什么用，大家可以参考：http://www.cnblogs.com/tzyy/p/5193811.html

总之，最后我们在package.json中放入了以下内容：

{ "name": "nodeTest", "version": "1.0.0", "description": "Hyperledger Fabric Node SDK Test Application", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "dependencies": { "fabric-ca-client": "^1.0.0", "fabric-client": "^1.0.0" }, "author": "Devin Zeng", "license": "Apache-2.0", "keywords": [ "Hyperledger", "Fabric", "Test", "Application" ]
}

最主要的就是dependencies，这里我们放了Fabric CA Client和Fabric Node SDK的Client，虽然本示例中没用到CA Client，但是以后会用到，所以先放在这里了。

编辑保存好该文件后，我们就可以运行npm install命令来下载所有相关的依赖模块，但是由于npm服务器在国外，所以下载可能会很慢，感谢淘宝为我们提供了国内的npm镜像，使得安装npm模块快很多。运行的命令是：

npm install --registry=https://registry.npm.taobao.org

运行完毕后我们查看一下nodeTest目录，可以看到多了一个node_modules文件夹。这里就是使用刚才的命令下载下来的所有依赖包。

2.编写对Fabric的Query方法

下面我们新建一个query.js文件，开始我们的Fabric Node SDK编码工作。由于代码比较长，所以我就不分步讲了，直接在代码中增加注释，将完整代码贴出来：

'use strict';var hfc = require('fabric-client');
var path = require('path');
var sdkUtils = require('fabric-client/lib/utils')
var fs = require('fs');
var options = { user_id: 'Admin@org1.example.com', msp_id:'Org1MSP', channel_id: 'mychannel', chaincode_id: 'mycc', network_url: 'grpcs://localhost:7051',//因为启用了TLS，所以是grpcs,如果没有启用TLS，那么就是grpc privateKeyFolder:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/keystore', signedCert:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/signcerts/Admin@org1.example.com-cert.pem', tls_cacerts:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt', server_hostname: "peer0.org1.example.com"
};var channel = {};
var client = null;
const getKeyFilesInDir = (dir) => {
//该函数用于找到keystore目录下的私钥文件的路径 var files = fs.readdirSync(dir) var keyFiles = [] files.forEach((file_name) => { let filePath = path.join(dir, file_name) if (file_name.endsWith('_sk')) { keyFiles.push(filePath) } }) return keyFiles
}
Promise.resolve().then(() => { console.log("Load privateKey and signedCert"); client = new hfc(); var    createUserOpt = { username: options.user_id, mspid: options.msp_id, cryptoContent: { privateKey: getKeyFilesInDir(options.privateKeyFolder)[0], signedCert: options.signedCert } }
//以上代码指定了当前用户的私钥，证书等基本信息
return sdkUtils.newKeyValueStore({ path: "/tmp/fabric-client-stateStore/" }).then((store) => { client.setStateStore(store) return client.createUser(createUserOpt) })
}).then((user) => { channel = client.newChannel(options.channel_id); let data = fs.readFileSync(options.tls_cacerts); let peer = client.newPeer(options.network_url, { pem: Buffer.from(data).toString(), 'ssl-target-name-override': options.server_hostname } ); peer.setName("peer0"); //因为启用了TLS，所以上面的代码就是指定TLS的CA证书 channel.addPeer(peer); return;
}).then(() => { console.log("Make query"); var transaction_id = client.newTransactionID(); console.log("Assigning transaction_id: ", transaction_id._transaction_id);
//构造查询request参数 const request = { chaincodeId: options.chaincode_id, txId: transaction_id, fcn: 'query', args: ['a'] }; return channel.queryByChaincode(request);
}).then((query_responses) => { console.log("returned from query"); if (!query_responses.length) { console.log("No payloads were returned from query"); } else { console.log("Query result count = ", query_responses.length) } if (query_responses[0] instanceof Error) { console.error("error from query = ", query_responses[0]); } console.log("Response is ", query_responses[0].toString());//打印返回的结果
}).catch((err) => { console.error("Caught Error", err);
});

编写完代码，我们想要测试一下我们的代码是否靠谱，直接运行

node query.js

即可，我们可以看到，a账户的余额是90元。

studyzy@ubuntu1:~/nodeTest$ node query.js
Load privateKey and signedCert
Make query
Assigning transaction_id:  ee3ac35d40d8510813546a2216ad9c0d91213b8e1bba9b7fe19cfeff3014e38a
returned from query
Query result count =  1
Response is  90

为什么a账户是90？因为我们跑e2e_cli的Fabric网络时，系统会自动安装Example02的ChainCode，然后自动跑查询，转账等操作。

3.编写对Fabric的Invoke方法

相比较于Query方法，Invoke方法要复杂的多，主要是因为Invoke需要和Orderer通信，而且发起了Transaction之后，还要设置EventHub来接收消息。下面贴出invoke.js的全部内容，对于比较重要的部分我进行了注释:

'use strict';var hfc = require('fabric-client');
var path = require('path');
var util = require('util');
var sdkUtils = require('fabric-client/lib/utils')
const fs = require('fs');
var options = { user_id: 'Admin@org1.example.com', msp_id:'Org1MSP', channel_id: 'mychannel', chaincode_id: 'mycc', peer_url: 'grpcs://localhost:7051',//因为启用了TLS，所以是grpcs,如果没有启用TLS，那么就是grpc event_url: 'grpcs://localhost:7053',//因为启用了TLS，所以是grpcs,如果没有启用TLS，那么就是grpc orderer_url: 'grpcs://localhost:7050',//因为启用了TLS，所以是grpcs,如果没有启用TLS，那么就是grpc privateKeyFolder:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/keystore', signedCert:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/signcerts/Admin@org1.example.com-cert.pem', peer_tls_cacerts:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt', orderer_tls_cacerts:'/home/studyzy/go/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/ordererOrganizations/example.com/orderers/orderer.example.com/tls/ca.crt', server_hostname: "peer0.org1.example.com"
};var channel = {};
var client = null;
var targets = [];
var tx_id = null;
const getKeyFilesInDir = (dir) => {
//该函数用于找到keystore目录下的私钥文件的路径 const files = fs.readdirSync(dir) const keyFiles = [] files.forEach((file_name) => { let filePath = path.join(dir, file_name) if (file_name.endsWith('_sk')) { keyFiles.push(filePath) } }) return keyFiles
}
Promise.resolve().then(() => { console.log("Load privateKey and signedCert"); client = new hfc(); var    createUserOpt = { username: options.user_id, mspid: options.msp_id, cryptoContent: { privateKey: getKeyFilesInDir(options.privateKeyFolder)[0], signedCert: options.signedCert } }
//以上代码指定了当前用户的私钥，证书等基本信息
return sdkUtils.newKeyValueStore({ path: "/tmp/fabric-client-stateStore/" }).then((store) => { client.setStateStore(store) return client.createUser(createUserOpt) })
}).then((user) => { channel = client.newChannel(options.channel_id); let data = fs.readFileSync(options.peer_tls_cacerts); let peer = client.newPeer(options.peer_url, { pem: Buffer.from(data).toString(), 'ssl-target-name-override': options.server_hostname } ); //因为启用了TLS，所以上面的代码就是指定Peer的TLS的CA证书 channel.addPeer(peer); //接下来连接Orderer的时候也启用了TLS，也是同样的处理方法 let odata = fs.readFileSync(options.orderer_tls_cacerts); let caroots = Buffer.from(odata).toString(); var orderer = client.newOrderer(options.orderer_url, { 'pem': caroots, 'ssl-target-name-override': "orderer.example.com" }); channel.addOrderer(orderer); targets.push(peer); return;
}).then(() => { tx_id = client.newTransactionID(); console.log("Assigning transaction_id: ", tx_id._transaction_id);
//发起转账行为，将a->b 10元 var request = { targets: targets, chaincodeId: options.chaincode_id, fcn: 'invoke', args: ['a', 'b', '10'], chainId: options.channel_id, txId: tx_id }; return channel.sendTransactionProposal(request);
}).then((results) => { var proposalResponses = results[0]; var proposal = results[1]; var header = results[2]; let isProposalGood = false; if (proposalResponses && proposalResponses[0].response && proposalResponses[0].response.status === 200) { isProposalGood = true; console.log('transaction proposal was good'); } else { console.error('transaction proposal was bad'); } if (isProposalGood) { console.log(util.format( 'Successfully sent Proposal and received ProposalResponse: Status - %s, message - "%s", metadata - "%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, header: header }; // set the transaction listener and set a timeout of 30sec // if the transaction did not get committed within the timeout period, // fail the test 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 let data = fs.readFileSync(options.peer_tls_cacerts); let grpcOpts = { pem: Buffer.from(data).toString(), 'ssl-target-name-override': options.server_hostname } eh.setPeerAddr(options.event_url,grpcOpts); 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); 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.error('Failed to send proposal due to error: ' + err.stack ? err.stack : err); return 'Failed to send proposal due to error: ' + err.stack ? err.stack : 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.error('Failed to send transaction due to error: ' + err.stack ? err .stack : err); return 'Failed to send transaction due to error: ' + err.stack ? err.stack : err;
});

三.测试

推荐使用postman进行测试，可以按照https://github.com/hyperledger/fabric-samples/tree/release/balance-transfer这个例子中演示的步骤进行

cd fabric-samples/balance-transfer/

docker-compose -f artifacts/docker-compose.yaml up

Login Request

Register and enroll new users in Organization - Org1:
在Termial中输入以下命令

curl -s -X POST http://localhost:4000/users -H "content-type: application/x-www-form-urlencoded" -d 'username=Jim&orgName=org1'

OUTPUT:

{"success": true,"secret": "RaxhMgevgJcm","message": "Jim enrolled Successfully","token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE0OTQ4NjU1OTEsInVzZXJuYW1lIjoiSmltIiwib3JnTmFtZSI6Im9yZzEiLCJpYXQiOjE0OTQ4NjE5OTF9.yWaJhFDuTvMQRaZIqg20Is5t-JJ_1BP58yrNLOKxtNI"
}

或者在postman中

四.总结

这只是简单的测试Node SDK是否可用，如果我们要做项目，那么就会复杂很多，可以参考官方的两个项目：

https://github.com/hyperledger/fabric-samples/tree/release/balance-transfer

https://github.com/IBM-Blockchain/marbles