Hyperledger Fabric Rest API服務開發教程【含源碼】

Hyperledger Fabric 提供了軟件開發包/SDK以幫助開發者訪問fabric網絡 和部署在網絡上的鏈碼，但是Hyperledger Fabric官方沒有提供簡單易用的REST API訪問接口，在這個教程里我們將學習如何利用Hyperledger Fabric的SDK 來開發REST API服務器。

1、系統結構概述

相關推薦：H..Fabric Java 開發教程?|?H..Fabric Nodejs開發教程

整個系統包含兩個物理節點：

• Fabric節點：運行Fabric示例中的First Network，并且實例化了Fabcar鏈碼
• API服務器節點：運行REST API Server代碼供外部訪問

下面是部署在AWS上的兩個節點實例的情況：

首先參考官方文檔安裝hyperledger fabric。

然后運行腳本fabcar/startFabric.sh：

1 2	cd fabric-samples/fabcar ./startFabric.sh

上述腳本運行之后，我們就得到一個正常運轉的Hyperledger Fabric網絡（著名的演示網絡First Network），包含2個機構/4個對等節點， 通道為mychannel，鏈碼Fabcar安裝在全部4個對等節點上并且在mychannel上激活。賬本中有10條車輛記錄，這是調用 合約的initLedger方法的結果。

現在我們為REST API Server準備身份標識數據。使用fabcar/javascript創建一個用戶標識user1，我們將在REST API Server 中使用這個身份標識：

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cd javascript npm install node enrollAdmin.js node registerUser.js ls wallet/user1

運行結果如下：

現在Rest API Server需要的東西都備齊了：

• org1的連接配置文件：first-network/connection-org1.json
• Node.js包文件：fabcar/package.json
• User1身份錢包：fabcar/javascript/wallet/user1/

后面我們會把這些數據文件拷貝到Rest API Server。

2、Rest API Server設計

我們使用ExressJS來開發API服務，利用query.js和invoke.js 中的代碼實現與fabric交互的邏輯。API設計如下：

• GET /api/queryallcars：返回全部車輛記錄
• GET /api/query/CarID：返回指定ID的車輛記錄
• POST /api/addcar/：添加一條新的車輛記錄
• PUT /api/changeowner/CarID：修改指定ID的車輛記錄

3、Rest API Server代碼實現

apiserver.js代碼如下：

express

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var bodyParser = require('body-parser');var app = express(); app.use(bodyParser.json());// Setting for Hyperledger Fabric const { FileSystemWallet, Gateway } = require('fabric-network'); const path = require('path'); const ccpPath = path.resolve(__dirname, '.', 'connection-org1.json');app.get('/api/queryallcars', async function (req, res) {try {// Create a new file system based wallet for managing identities.const walletPath = path.join(process.cwd(), 'wallet');const wallet = new FileSystemWallet(walletPath);console.log(`Wallet path: ${walletPath}`);// Check to see if we've already enrolled the user.const userExists = await wallet.exists('user1');if (!userExists) {console.log('An identity for the user "user1" does not exist in the wallet');console.log('Run the registerUser.js application before retrying');return;}// Create a new gateway for connecting to our peer node.const gateway = new Gateway();await gateway.connect(ccpPath, { wallet, identity: 'user1', discovery: { enabled: true, asLocalhost: false } });// Get the network (channel) our contract is deployed to.const network = await gateway.getNetwork('mychannel');// Get the contract from the network.const contract = network.getContract('fabcar');// Evaluate the specified transaction.// queryCar transaction - requires 1 argument, ex: ('queryCar', 'CAR4')// queryAllCars transaction - requires no arguments, ex: ('queryAllCars')const result = await contract.evaluateTransaction('queryAllCars');console.log(`Transaction has been evaluated, result is: ${result.toString()}`);res.status(200).json({response: result.toString()});} catch (error) {console.error(`Failed to evaluate transaction: ${error}`);res.status(500).json({error: error});process.exit(1);} });app.get('/api/query/:car_index', async function (req, res) {try {// Create a new file system based wallet for managing identities.const walletPath = path.join(process.cwd(), 'wallet');const wallet = new FileSystemWallet(walletPath);console.log(`Wallet path: ${walletPath}`);// Check to see if we've already enrolled the user.const userExists = await wallet.exists('user1');if (!userExists) {console.log('An identity for the user "user1" does not exist in the wallet');console.log('Run the registerUser.js application before retrying');return;}// Create a new gateway for connecting to our peer node.const gateway = new Gateway();await gateway.connect(ccpPath, { wallet, identity: 'user1', discovery: { enabled: true, asLocalhost: false } });// Get the network (channel) our contract is deployed to.const network = await gateway.getNetwork('mychannel');// Get the contract from the network.const contract = network.getContract('fabcar');// Evaluate the specified transaction.// queryCar transaction - requires 1 argument, ex: ('queryCar', 'CAR4')// queryAllCars transaction - requires no arguments, ex: ('queryAllCars')const result = await contract.evaluateTransaction('queryCar', req.params.car_index);console.log(`Transaction has been evaluated, result is: ${result.toString()}`);res.status(200).json({response: result.toString()});} catch (error) {console.error(`Failed to evaluate transaction: ${error}`);res.status(500).json({error: error});process.exit(1);} });app.post('/api/addcar/', async function (req, res) {try {// Create a new file system based wallet for managing identities.const walletPath = path.join(process.cwd(), 'wallet');const wallet = new FileSystemWallet(walletPath);console.log(`Wallet path: ${walletPath}`);// Check to see if we've already enrolled the user.const userExists = await wallet.exists('user1');if (!userExists) {console.log('An identity for the user "user1" does not exist in the wallet');console.log('Run the registerUser.js application before retrying');return;}// Create a new gateway for connecting to our peer node.const gateway = new Gateway();await gateway.connect(ccpPath, { wallet, identity: 'user1', discovery: { enabled: true, asLocalhost: false } });// Get the network (channel) our contract is deployed to.const network = await gateway.getNetwork('mychannel');// Get the contract from the network.const contract = network.getContract('fabcar');// Submit the specified transaction.// createCar transaction - requires 5 argument, ex: ('createCar', 'CAR12', 'Honda', 'Accord', 'Black', 'Tom')// changeCarOwner transaction - requires 2 args , ex: ('changeCarOwner', 'CAR10', 'Dave')await contract.submitTransaction('createCar', req.body.carid, req.body.make, req.body.model, req.body.colour, req.body.owner);console.log('Transaction has been submitted');res.send('Transaction has been submitted');// Disconnect from the gateway.await gateway.disconnect();} catch (error) {console.error(`Failed to submit transaction: ${error}`);process.exit(1);} })app.put('/api/changeowner/:car_index', async function (req, res) {try {// Create a new file system based wallet for managing identities.const walletPath = path.join(process.cwd(), 'wallet');const wallet = new FileSystemWallet(walletPath);console.log(`Wallet path: ${walletPath}`);// Check to see if we've already enrolled the user.const userExists = await wallet.exists('user1');if (!userExists) {console.log('An identity for the user "user1" does not exist in the wallet');console.log('Run the registerUser.js application before retrying');return;}// Create a new gateway for connecting to our peer node.const gateway = new Gateway();await gateway.connect(ccpPath, { wallet, identity: 'user1', discovery: { enabled: true, asLocalhost: false } });// Get the network (channel) our contract is deployed to.const network = await gateway.getNetwork('mychannel');// Get the contract from the network.const contract = network.getContract('fabcar');// Submit the specified transaction.// createCar transaction - requires 5 argument, ex: ('createCar', 'CAR12', 'Honda', 'Accord', 'Black', 'Tom')// changeCarOwner transaction - requires 2 args , ex: ('changeCarOwner', 'CAR10', 'Dave')await contract.submitTransaction('changeCarOwner', req.params.car_index, req.body.owner);console.log('Transaction has been submitted');res.send('Transaction has been submitted');// Disconnect from the gateway.await gateway.disconnect();} catch (error) {console.error(`Failed to submit transaction: ${error}`);process.exit(1);} })app.listen(8080);

代碼中對原來fabcar的query.js和invoke.js修改如下：

• ccpPath修改為當前目錄，因為我們要使用同一路徑下的連接配置文件connection-org1.json
• 在gateway.connect調用中，修改選項discovery.asLocalhost為false

4、Rest API Server的連接配置文件

API服務依賴于連接配置文件來正確連接fabric網絡。文件 connection-org1.json 可以直接從 fabric網絡中獲取：

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{"name": "first-network-org1","version": "1.0.0","client": {"organization": "Org1","connection": {"timeout": {"peer": {"endorser": "300"}}}},"organizations": {"Org1": {"mspid": "Org1MSP","peers": ["peer0.org1.example.com","peer1.org1.example.com"],"certificateAuthorities": ["ca.org1.example.com"]}},"peers": {"peer0.org1.example.com": {"url": "grpcs://localhost:7051","tlsCACerts": {"pem": "-----BEGIN CERTIFICATE-----\nMIICVjCCAf2gAwIBAgIQEB1sDT11gzTv0/N4cIGoEjAKBggqhkjOPQQDA jB2MQsw\nCQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy\nYW5jaXNjbzEZMBcGA1UEChMQb3JnMS5leGF tcGxlLmNvbTEfMB0GA1UEAxMWdGxz\nY2Eub3JnMS5leGFtcGxlLmNvbTAeFw0xOTA5MDQwMjQzMDBaFw0yOTA5MDEwMjQz\nMDBaMHYxCzAJB gNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQH\nEw1TYW4gRnJhbmNpc2NvMRkwFwYDVQQKExBvcmcxLmV4YW1wbGUuY29tM R8wHQYD\nVQQDExZ0bHNjYS5vcmcxLmV4YW1wbGUuY29tMFkwEwYHKoZIzj0CAQYIKoZIzj0D\nAQcDQgAEoN0qd5hM2SDfvGzNjTCXuQqyk+X K4VISa16/y9iXBPpa0onyAXJuv7T0\noPf+mh3T7/g8uYtV2bwTpT2XFO3Q6KNtMGswDgYDVR0PAQH/BAQDAgGmMB0GA1Ud\nJQQWMBQGCCsGA QUFBwMCBggrBgEFBQcDATAPBgNVHRMBAf8EBTADAQH/MCkGA1Ud\nDgQiBCCalpyChmrLtpgOll6TVmlMOO/2iiyI2PadNPsIYx51mTAKBggqh kjOPQQD\nAgNHADBEAiBLNoAYWe9LvoxxBxl3sUM64kl7rx6dI3JU+dJG6FRxWgIgCu1ONEyp\nfux9lZWr6gcrIdsn/8fQuWiOIbAgq0HSr60 =\n-----END CERTIFICATE-----\n"},"grpcOptions": {"ssl-target-name-override": "peer0.org1.example.com","hostnameOverride": "peer0.org1.example.com"}},"peer1.org1.example.com": {"url": "grpcs://localhost:8051","tlsCACerts": {"pem": "-----BEGIN CERTIFICATE-----\nMIICVjCCAf2gAwIBAgIQEB1sDT11gzTv0/N4cIGoEjAKBggqhkjOPQQDA jB2MQsw\nCQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy\nYW5jaXNjbzEZMBcGA1UEChMQb3JnMS5leGF tcGxlLmNvbTEfMB0GA1UEAxMWdGxz\nY2Eub3JnMS5leGFtcGxlLmNvbTAeFw0xOTA5MDQwMjQzMDBaFw0yOTA5MDEwMjQz\nMDBaMHYxCzAJB gNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQH\nEw1TYW4gRnJhbmNpc2NvMRkwFwYDVQQKExBvcmcxLmV4YW1wbGUuY29tM R8wHQYD\nVQQDExZ0bHNjYS5vcmcxLmV4YW1wbGUuY29tMFkwEwYHKoZIzj0CAQYIKoZIzj0D\nAQcDQgAEoN0qd5hM2SDfvGzNjTCXuQqyk+X K4VISa16/y9iXBPpa0onyAXJuv7T0\noPf+mh3T7/g8uYtV2bwTpT2XFO3Q6KNtMGswDgYDVR0PAQH/BAQDAgGmMB0GA1Ud\nJQQWMBQGCCsGA QUFBwMCBggrBgEFBQcDATAPBgNVHRMBAf8EBTADAQH/MCkGA1Ud\nDgQiBCCalpyChmrLtpgOll6TVmlMOO/2iiyI2PadNPsIYx51mTAKBggqh kjOPQQD\nAgNHADBEAiBLNoAYWe9LvoxxBxl3sUM64kl7rx6dI3JU+dJG6FRxWgIgCu1ONEyp\nfux9lZWr6gcrIdsn/8fQuWiOIbAgq0HSr60 =\n-----END CERTIFICATE-----\n"},"grpcOptions": {"ssl-target-name-override": "peer1.org1.example.com","hostnameOverride": "peer1.org1.example.com"}}},"certificateAuthorities": {"ca.org1.example.com": {"url": "https://localhost:7054","caName": "ca-org1","tlsCACerts": {"pem": "-----BEGIN CERTIFICATE-----\nMIICUTCCAfegAwIBAgIQSiMHm4n9QvhD6wltAHkZPTAKBggqhkjOPQQDA jBzMQsw\nCQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMNU2FuIEZy\nYW5jaXNjbzEZMBcGA1UEChMQb3JnMS5leGF tcGxlLmNvbTEcMBoGA1UEAxMTY2Eu\nb3JnMS5leGFtcGxlLmNvbTAeFw0xOTA5MDQwMjQzMDBaFw0yOTA5MDEwMjQzMDBa\nMHMxCzAJBgNVB AYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1T\nYW4gRnJhbmNpc2NvMRkwFwYDVQQKExBvcmcxLmV4YW1wbGUuY29tMRwwG gYDVQQD\nExNjYS5vcmcxLmV4YW1wbGUuY29tMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE\nz93lOhLJG93uJQgnh93QcPPal5NQXQnAutF KYkun/eMHMe23wNPd0aJhnXdCjWF8\nMRHVAjtPn4NVCJYiTzSAnaNtMGswDgYDVR0PAQH/BAQDAgGmMB0GA1UdJQQWMBQG\nCCsGAQUFBwMCB ggrBgEFBQcDATAPBgNVHRMBAf8EBTADAQH/MCkGA1UdDgQiBCDK\naDhLwl3RBO6eKgHh4lHJovIyDJO3jTNb1ix1W86bFjAKBggqhkjOPQQDA gNIADBF\nAiEA8KTKkjQwb1TduTWWkmsLmKdxrlE6/H7CfsdeGE+onewCIHJ1S0nLhbWYv+G9\nTbAFlNCpqr0AQefaRT3ghdURrlbo\n----- END CERTIFICATE-----\n"},"httpOptions": {"verify": false}}} }

當fabcar/startFabric.sh執行時，我們可以交叉檢查證書的傳播是否正確。 peer0.org1和 peer1.org1 的證書是org1的 TLS root CA 證書簽名的。

注意所有的節點都以localhost引用，我們稍后會將其修改為Fabric Node的 公開IP地址。

5、用戶身份標識

我們已經在Fabric節點上生成了一個用戶標識user1并保存在wallet目錄中， 我們可以看到有三個對應的文件：私鑰、公鑰和證書對象：

稍后我們會把這些文件拷貝到Rest API Server上。

6、安裝Rest API Server節點

1、首先在Rest API Server節點上安裝npm、node：

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sudo apt-get update sudo apt install curl curl -sL https://deb.nodesource.com/setup_8.x | sudo bash - sudo apt install -y nodejs sudo apt-get install build-essentialnode -v npm -v

驗證結果如下：

2、然后在Rest API Server上創建一個目錄：

1 2	mkdir apiserver cd apiserver

3、接下來將下面的文件從Fabric節點拷貝到Rest API Server節點。我們 利用loccalhost在兩個EC2實例間拷貝：

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# localhost (update your own IP of the two servers) # temp is an empty directory cd temp scp -i ~/Downloads/aws.pem ubuntu@[Fabric-Node-IP]:/home/ubuntu/fabric-samples/first-network/connection-org1.json . scp -i ~/Downloads/aws.pem ubuntu@[Fabric-Node-IP]:/home/ubuntu/fabric-samples/fabcar/javascript/package.json . scp -r -i ~/Downloads/aws.pem ubuntu@[Fabric-Node-IP]:/home/ubuntu/fabric-samples/fabcar/javascript/wallet/user1/ . scp -r -i ~/Downloads/aws.pem * ubuntu@[API-Server-Node-IP]:/home/ubuntu/apiserver/

運行結果如下：

4、可以看到現在所有的文件都拷貝到Rest API Server了，為了保持一致，我們將user1/改名為wallet/user1/：

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cd apiserver mkdir wallet mv user1 wallet/user1

運行結果如下：

5、現在在Rest API Server上創建上面的apiserver.js文件。

6、修改連接配置文件connection-org1.json 中的fabric節點的ip地址：

1	sed -i 's/localhost/[Fabric-Node-IP]/g' connection-org1.json

運行結果如下：

7、在/etc/hosts中增加條目以便可以正確解析fabric節點的IP：

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127.0.0.1 localhost [Fabric-Node-IP] orderer.example.com [Fabric-Node-IP] peer0.org1.example.com [Fabric-Node-IP] peer1.org1.example.com [Fabric-Node-IP] peer0.org2.example.com [Fabric-Node-IP] peer1.org2.example.com

運行結果如下：

8、安裝必要的依賴包：

1 2	npm install npm install express body-parser --save

9、萬事俱備，啟動Rest API Server：

1	node apiserver.js

7、訪問API

我們的API服務在8080端口監聽，在下面的示例中，我們使用curl來 演示如何訪問。

1、查詢所有車輛記錄

1	curl http://[API-Server-Node-IP]:8080/api/queryallcars

運行結果如下：

2、添加新的車輛記錄并查詢

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curl -d '{"carid":"CAR12","make":"Honda","model":"Accord","colour":"black","owner":"Tom"}' -H "Content-Type: application/json" -X POST http://[API-Server-Node-IP]:8080/api/addcarcurl http://[API-Server-Node-IP]:8080/api/query/CAR12

運行結果如下：

3、修改車輛所有者并再次查詢

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curl http://[API-Server-Node-IP]:8080/api/query/CAR4curl -d '{"owner":"KC"}' -H "Content-Type: application/json" -X PUT http://[API-Server-Node-IP]:8080/api/changeowner/CAR4curl http://[API-Server-Node-IP]:8080/api/query/CAR4

運行結果如下：

我們也可以用postman得到同樣的結果：

---

原文鏈接：An Implementation of API Server for Hyperledger Fabric Network

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