使用Fabric Node SDK進行Invoke和Query

時間 2019-11-30

標籤使用 fabric node sdk 進行 invoke query 简体版

原文原文鏈接

前面的文章都是在講解Fabric網絡的搭建和ChainCode的開發，那麼在ChainCode開發完畢後，咱們就須要使用Fabric SDK作應用程序的開發了。官方雖然提供了Node.JS，Java，Go，Python等多種語言的SDK，可是因爲整個Fabric太新了，不少SDK還不成熟和完善，因此我採用Node JS的SDK，畢竟這個是功能畢竟齊全，並且也是官方示例的時候使用的SDK。因爲我歷來沒有接觸過Node.JS的開發，對這個語言理解不深，因此講的比較膚淺，但願你們見諒。html

1.環境準備

Node.js是一個跨平臺的語言，能夠在Linux，Window和Mac上安裝，咱們在開發的時候能夠在Windows下開發，最後生產環境通常都是Linux，因此咱們這裏就以Ubuntu爲例。Fabric Node SDK支持的Node版本是v6，不支持最新的v8版本。NodeJS官方給咱們提供了很方便的安裝方法，具體文檔在：https://nodejs.org/en/download/package-manager/#debian-and-ubuntu-based-linux-distributionsnode

咱們只須要執行如下命令便可安裝NodeJS的最新v6版本：linux

curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
sudo apt-get install -y nodejs

安裝完成後咱們可使用如下兩個命令來查看安裝的Node版本和npm版本。

node –v
npm -v

關於NPM，這個是一個包管理器，我以爲很像VS裏面的NuGet，關於NPM的基礎知識，咱們能夠參考這篇博客：http://www.ruanyifeng.com/blog/2016/01/npm-install.html

只要安裝好node和npm，接下來咱們就能夠進行Fabric Node SDK Application的開發了。

因爲咱們想基於官方Example的e2e_cli裏面的Fabric網絡來寫程序，關於Fabric網絡的搭建我就很少說，你們能夠參考我以前的博客。總之結果就是咱們如今已經成功運行了e2e_cli這個網絡，也就是說Example02這個ChainCode已經安裝部署，而且測試經過了，咱們接下來只是換用Node SDK的方式進行查詢和調用。

2.編寫package.json並下載依賴模塊

咱們首先在當前用戶的根目錄創建一個nodeTest的文件夾，用於存放咱們關於node的相關項目文件，而後在其中新建一個包配置文件，package.json

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

在這個文件中，咱們能夠定義不少項目相關的屬性，這篇博客詳細的介紹了每一個屬性有什麼用，你們能夠參考：http://www.cnblogs.com/tzyy/p/5193811.html

總之，最後咱們在package.json中放入瞭如下內容：

{ 
     "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，這裏咱們放了Fabric CA Client和Fabric Node SDK的Client，雖然本示例中沒用到CA Client，可是之後會用到，因此先放在這裏了。git

編輯保存好該文件後，咱們就能夠運行npm install命令來下載全部相關的依賴模塊，可是因爲npm服務器在國外，因此下載可能會很慢，感謝淘寶爲咱們提供了國內的npm鏡像，使得安裝npm模塊快不少。運行的命令是：

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

運行完畢後咱們查看一下nodeTest目錄，能夠看到多了一個node_modules文件夾。這裏就是使用剛纔的命令下載下來的全部依賴包。

2.編寫對Fabric的Query方法

下面咱們新建一個query.js文件，開始咱們的Fabric Node SDK編碼工做。因爲代碼比較長，因此我就不分步講了，直接在代碼中增長註釋，將完整代碼貼出來：github

'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',//由於啓用了TLS，因此是grpcs,若是沒有啓用TLS，那麼就是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) => { 
//該函數用於找到keystore目錄下的私鑰文件的路徑 
    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 } 
        } 
//以上代碼指定了當前用戶的私鑰，證書等基本信息 
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"); 
    //由於啓用了TLS，因此上面的代碼就是指定TLS的CA證書 
    channel.addPeer(peer); 
    return; 
}).then(() => { 
    console.log("Make query"); 
    var transaction_id = client.newTransactionID(); 
    console.log("Assigning transaction_id: ", transaction_id._transaction_id); 
//構造查詢request參數 
    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());//打印返回的結果 
}).catch((err) => { 
    console.error("Caught Error", err); 
});

編寫完代碼，咱們想要測試一下咱們的代碼是否靠譜，直接運行npm

node query.js

便可，咱們能夠看到，a帳戶的餘額是90元。json

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

爲何a帳戶是90？由於咱們跑e2e_cli的Fabric網絡時，系統會自動安裝Example02的ChainCode，而後自動跑查詢，轉帳等操做。ubuntu

3.編寫對Fabric的Invoke方法

相比較於Query方法，Invoke方法要複雜的多，主要是由於Invoke須要和Orderer通訊，並且發起了Transaction以後，還要設置EventHub來接收消息。下面貼出invoke.js的所有內容，對於比較重要的部分我進行了註釋:promise

'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',//由於啓用了TLS，因此是grpcs,若是沒有啓用TLS，那麼就是grpc 
    event_url: 'grpcs://localhost:7053',//由於啓用了TLS，因此是grpcs,若是沒有啓用TLS，那麼就是grpc 
    orderer_url: 'grpcs://localhost:7050',//由於啓用了TLS，因此是grpcs,若是沒有啓用TLS，那麼就是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) => { 
//該函數用於找到keystore目錄下的私鑰文件的路徑 
        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 } 
         } 
//以上代碼指定了當前用戶的私鑰，證書等基本信息 
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 
        } 
    ); 
    //由於啓用了TLS，因此上面的代碼就是指定Peer的TLS的CA證書 
    channel.addPeer(peer); 
    //接下來鏈接Orderer的時候也啓用了TLS，也是一樣的處理方法 
    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); 
//發起轉帳行爲，將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(); 
        //接下來設置EventHub，用於監聽Transaction是否成功寫入，這裏也是啓用了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註冊事件的處理辦法 
            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; 
});

保存文件並退出，接下來測試一下咱們的代碼，運行：bash

node invoke.js

咱們能夠看到系統返回以下結果：

Load privateKey and signedCert 
Assigning transaction_id:  1adbf20ace0d1601b00cc2b9dfdd4a431cfff9a13f6a6f5e5e4a80c897e0f7a8 
transaction proposal was good 
Successfully sent Proposal and received ProposalResponse: Status - 200, message - "OK", metadata - "", endorsement signature: 0D x��N��n�#���/�G���QD�w�����As� \]��FfWҡ�+������=m9I���� 6�i 
info: [EventHub.js]: _connect - options {"grpc.ssl_target_name_override":"peer0.org1.example.com","grpc.default_authority":"peer0.org1.example.com"} 
The transaction has been committed on peer localhost:7053 
  event promise all complete and testing complete 
Successfully sent transaction to the orderer.

從打印出的結果看，咱們的轉帳已經成功了，咱們能夠從新調用以前寫的query.js從新查詢，能夠看到a帳戶的餘額已經變少了10元。