Hyperledger Fabric 实战（1） fabric-sdk-node

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’;
/*

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

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;

// 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’);
}

// 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