Hyperledger Fabric 实战（1） fabric-sdk-node

淡淡的烟草味﹌ 2022-03-30 04:18 242阅读 0赞

### Hyperledger Fabric 实战（1） fabric-sdk-node ###

*   *  关于Fabric SDK
     *  安装环境
     *  创建node http服务器
     *  invoke方法内容如下:
     *  query方法内容如下:
     *  注意

## 关于Fabric SDK ##

目前Fabric官方提供了四种语言版本的SDK，分别如下：  
1 Fabric Nodejs SDK  
2 Fabric Java SDK  
3 Fabric Go SDK  
4 Fabric Python SDK

由于1.2版本没有java sdk(1.3版本java sdk 貌似坑也很多) Go 和 python相比node sdk 坑也多.  
且Node.js SDK的编程模型得到改善,node.js的链码开发更直观，可更专注于业务逻辑,所以建议选择node sdk.

## 安装环境 ##

首先安装node  
版本最好为8.9,9.x以上不支持  
node runtime LTS version 8.9.0 or higher, up to 9.0 ( Node v9.0+ is not supported )  
npm tool version 5.5.1 or higher  
gulp command (must be installed globaly with npm install -g gulp)  
docker (not required if you only want to run the headless tests with npm test, see below)

## 创建node http服务器 ##

创建一个node-demo project  
app.js 里面的内容如下  
const http = require(‘http’);

const hostname = ‘127.0.0.1’;  
const port = 3000;

const server = http.createServer((req, res) => \{  
res.statusCode = 200;  
res.setHeader(‘Content-Type’, ‘text/plain’);  
res.end(‘Hello World\\n’);  
\});

server.listen(port, hostname, () => \{  
console.log(`Server running at http://${hostname}:${port}/`);  
\});  
package.json文件添加如下内容  
\{  
“name”: “fabcar”,  
“version”: “1.0.0”,  
“description”: “Hyperledger Fabric Car Sample Application”,  
“main”: “fabcar.js”,  
“scripts”: \{  
“test”: “echo “Error: no test specified” && exit 1”  
\},  
“dependencies”: \{  
“fabric-ca-client”: “~1.2.0”,  
“fabric-client”: “~1.2.0”,  
“grpc”: “^1.6.0”  
\},  
“author”: “Anthony O’Dowd”,  
“license”: “Apache-2.0”,  
“keywords”: \[  
“Hyperledger”,  
“Fabric”,  
“Car”,  
“Sample”,  
“Application”  
\]  
\}

## invoke方法内容如下: ##

‘use strict’;  
/\*

*  Copyright IBM Corp All Rights Reserved
 *  
 *  SPDX-License-Identifier: Apache-2.0  
    */  
    /*
 *  Chaincode Invoke  
    \*/

var Fabric\_Client = require(‘fabric-client’);  
var path = require(‘path’);  
var util = require(‘util’);  
var os = require(‘os’);

//  
var fabric\_client = new Fabric\_Client();

// setup the fabric network  
var channel = fabric\_client.newChannel(‘mychannel’);  
var peer = fabric\_client.newPeer(‘grpc://localhost:7051’);  
channel.addPeer(peer);  
var order = fabric\_client.newOrderer(‘grpc://localhost:7050’)  
channel.addOrderer(order);

//  
var member\_user = null;  
var store\_path = path.join(\_\_dirname, ‘hfc-key-store’);  
console.log(‘Store path:’+store\_path);  
var tx\_id = null;

// create the key value store as defined in the fabric-client/config/default.json ‘key-value-store’ setting  
Fabric\_Client.newDefaultKeyValueStore(\{ path: store\_path  
\}).then((state\_store) => \{  
// assign the store to the fabric client  
fabric\_client.setStateStore(state\_store);  
var crypto\_suite = Fabric\_Client.newCryptoSuite();  
// use the same location for the state store (where the users’ certificate are kept)  
// and the crypto store (where the users’ keys are kept)  
var crypto\_store = Fabric\_Client.newCryptoKeyStore(\{path: store\_path\});  
crypto\_suite.setCryptoKeyStore(crypto\_store);  
fabric\_client.setCryptoSuite(crypto\_suite);

// get the enrolled user from persistence, this user will sign all requests
    return fabric_client.getUserContext('user1', true);

\}).then((user\_from\_store) => \{  
if (user\_from\_store && user\_from\_store.isEnrolled()) \{  
console.log(‘Successfully loaded user1 from persistence’);  
member\_user = user\_from\_store;  
\} else \{  
throw new Error(‘Failed to get user1… run registerUser.js’);  
\}

// get a transaction id object based on the current user assigned to fabric client
    tx_id = fabric_client.newTransactionID();
    console.log("Assigning transaction_id: ", tx_id._transaction_id);
    
    // createCar chaincode function - requires 5 args, ex: args: ['CAR12', 'Honda', 'Accord', 'Black', 'Tom'],
    // changeCarOwner chaincode function - requires 2 args , ex: args: ['CAR10', 'Dave'],
    // must send the proposal to endorsing peers
    var request = {
    	//targets: let default to the peer assigned to the client
    	chaincodeId: 'fabcar',
    	fcn: '',
    	args: [''],
    	chainId: 'mychannel',
    	txId: tx_id
    };
    
    // send the transaction proposal to the peers
    return channel.sendTransactionProposal(request);

\}).then((results) => \{  
var proposalResponses = results\[0\];  
var proposal = results\[1\];  
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”’,  
proposalResponses\[0\].response.status, proposalResponses\[0\].response.message));

// build up the request for the orderer to have the transaction committed
    	var request = {
    		proposalResponses: proposalResponses,
    		proposal: proposal
    	};
    
    	// set the transaction listener and set a timeout of 30 sec
    	// if the transaction did not get committed within the timeout period,
    	// report a TIMEOUT status
    	var transaction_id_string = tx_id.getTransactionID(); //Get the transaction ID string to be used by the event processing
    	var promises = [];
    
    	var sendPromise = channel.sendTransaction(request);
    	promises.push(sendPromise); //we want the send transaction first, so that we know where to check status
    
    	// get an eventhub once the fabric client has a user assigned. The user
    	// is required bacause the event registration must be signed
    	let event_hub = channel.newChannelEventHub(peer);
    
    	// using resolve the promise so that result status may be processed
    	// under the then clause rather than having the catch clause process
    	// the status
    	let txPromise = new Promise((resolve, reject) => {
    		let handle = setTimeout(() => {
    			event_hub.unregisterTxEvent(transaction_id_string);
    			event_hub.disconnect();
    			resolve({event_status : 'TIMEOUT'}); //we could use reject(new Error('Trnasaction did not complete within 30 seconds'));
    		}, 3000);
    		event_hub.registerTxEvent(transaction_id_string, (tx, code) => {
    			// this is the callback for transaction event status
    			// first some clean up of event listener
    			clearTimeout(handle);
    
    			// now let the application know what happened
    			var return_status = {event_status : code, tx_id : transaction_id_string};
    			if (code !== 'VALID') {
    				console.error('The transaction was invalid, code = ' + code);
    				resolve(return_status); // we could use reject(new Error('Problem with the tranaction, event status ::'+code));
    			} else {
    				console.log('The transaction has been committed on peer ' + event_hub.getPeerAddr());
    				resolve(return_status);
    			}
    		}, (err) => {
    			//this is the callback if something goes wrong with the event registration or processing
    			reject(new Error('There was a problem with the eventhub ::'+err));
    		},
    			{disconnect: true} //disconnect when complete
    		);
    		event_hub.connect();
    
    	});
    	promises.push(txPromise);
    
    	return Promise.all(promises);
    } else {
    	console.error('Failed to send Proposal or receive valid response. Response null or status is not 200. exiting...');
    	throw new Error('Failed to send Proposal or receive valid response. Response null or status is not 200. exiting...');
    }

\}).then((results) => \{  
console.log(‘Send transaction promise and event listener promise have completed’);  
// check the results in the order the promises were added to the promise all list  
if (results && results\[0\] && results\[0\].status === ‘SUCCESS’) \{  
console.log(‘Successfully sent transaction to the orderer.’);  
\} else \{  
console.error('Failed to order the transaction. Error code: ’ + results\[0\].status);  
\}

if(results && results[1] && results[1].event_status === 'VALID') {
    	console.log('Successfully committed the change to the ledger by the peer');
    } else {
    	console.log('Transaction failed to be committed to the ledger due to ::'+results[1].event_status);
    }

\}).catch((err) => \{  
console.error('Failed to invoke successfully :: ’ + err);  
\});

## query方法内容如下: ##

‘use strict’;  
/\*

var Fabric\_Client = require(‘fabric-client’);  
var path = require(‘path’);  
var util = require(‘util’);  
var os = require(‘os’);

//  
var fabric\_client = new Fabric\_Client();

// setup the fabric network  
var channel = fabric\_client.newChannel(‘mychannel’);  
var peer = fabric\_client.newPeer(‘grpc://localhost:7051’);  
channel.addPeer(peer);

//  
var member\_user = null;  
var store\_path = path.join(\_\_dirname, ‘hfc-key-store’);  
console.log(‘Store path:’+store\_path);  
var tx\_id = null;

// get the enrolled user from persistence, this user will sign all requests
    return fabric_client.getUserContext('user1', true);

// queryCar chaincode function - requires 1 argument, ex: args: ['CAR4'],
    // queryAllCars chaincode function - requires no arguments , ex: args: [''],
    const request = {
    	//targets : --- letting this default to the peers assigned to the channel
    	chaincodeId: 'fabcar',
    	fcn: 'queryAllCars',
    	args: ['']
    };
    
    // send the query proposal to the peer
    return channel.queryByChaincode(request);

\}).then((query\_responses) => \{  
console.log(“Query has completed, checking results”);  
// query\_responses could have more than one results if there multiple peers were used as targets  
if (query\_responses && query\_responses.length == 1) \{  
if (query\_responses\[0\] instanceof Error) \{  
console.error("error from query = ", query\_responses\[0\]);  
\} else \{  
console.log("Response is ", query\_responses\[0\].toString());  
\}  
\} else \{  
console.log(“No payloads were returned from query”);  
\}  
\}).catch((err) => \{  
console.error('Failed to query successfully :: ’ + err);  
\});

## 注意 ##

使用这两个方法前我们需要:  
enrollAdmin 和 registerUser