这篇文章主要为大家展示了“Hyperledger Fabric中通过SDK和Hyperledger Fabric Blockchain交互的示例分析”，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下“Hyperledger Fabric中通过SDK和Hyperledger Fabric Blockchain交互的示例分析”这篇文章吧。
首先看 enroll (登录) admin 过程。
'use strict';
/*
* Copyright IBM Corp All Rights Reserved
*
* SPDX-License-Identifier: Apache-2.0
*/
/*
* Enroll the admin user
*/
var Fabric_Client = require('fabric-client');
var Fabric_CA_Client = require('fabric-ca-client');
var path = require('path');
var util = require('util');
var os = require('os');
//
var fabric_client = new Fabric_Client();
var fabric_ca_client = null;
var admin_user = null;
var member_user = null;
var store_path = path.join(__dirname, 'hfc-key-store');
console.log(' Store path:'+store_path);
// 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);
var tlsOptions = {
trustedRoots: [],
verify: false
};
// be sure to change the http to https when the CA is running TLS enabled
fabric_ca_client = new Fabric_CA_Client('http://localhost:7054', tlsOptions , 'ca.example.com', crypto_suite);
// first check to see if the admin is already enrolled
return fabric_client.getUserContext('admin', true);
}).then((user_from_store) => {
if (user_from_store && user_from_store.isEnrolled()) {
console.log('Successfully loaded admin from persistence');
admin_user = user_from_store;
return null;
} else {
// need to enroll it with CA server
return fabric_ca_client.enroll({
enrollmentID: 'admin',
enrollmentSecret: 'adminpw'
}).then((enrollment) => {
console.log('Successfully enrolled admin user "admin"');
return fabric_client.createUser(
{username: 'admin',
mspid: 'Org1MSP',
cryptoContent: { privateKeyPEM: enrollment.key.toBytes(), signedCertPEM: enrollment.certificate }
});
}).then((user) => {
admin_user = user;
return fabric_client.setUserContext(admin_user);
}).catch((err) => {
console.error('Failed to enroll and persist admin. Error: ' + err.stack ? err.stack : err);
throw new Error('Failed to enroll admin');
});
}
}).then(() => {
console.log('Assigned the admin user to the fabric client ::' + admin_user.toString());
}).catch((err) => {
console.error('Failed to enroll admin: ' + err);
});和其他所有程序一样， 首先需要加载相应的lib, 这里加载 fabric-client 和 fabric-ca-client.
var Fabric_Client = require("fabric-client");
var Fabric_CA_Client = require("fabric-ca-client");然后初始化Fabric_Client 和 Fabric_CA_Client对象
var fabric_client = new Fabric_Client();
var fabric_ca_client = null;
//fabric_ca_client = new Fabric_CA_Client("http://localhost:7054", tlsOption, "ca.example.com", crypto_suite)同时需要创建一个admin_user对象， 一个member_user对象，和一个目录对象用来存储用户持久化信息和证书信息。
var admin_user = null; var member_user = null; var store_path = path.join(__dirname, "hfc-key-store"); //指定当前目录下的hfc_key_store文件夹
接下来创建key-value store, 这里调用Fabric_Client的static方法， 并且根据fabric-client/config/default.json配置文件中的key-value-store决定实现， 也就是前面说的Node SDK的默认实现。
我们看源码：
Fabric_Client.newDefaultKeyValueStore({path: store_path})
.then((state_store) => {
//
})...此方法调用的是BaseClient.js的接口， 该接口位于 fabric-client/lib/BaseClient.js。
var sdkUtils = require('./utils.js');
static newDefaultKeyValueStore(options) {
return sdkUtils.newKeyValueStore(options);
}通过阅读源码发现， 实际上调用的是sdkUtils的方法， 该方法实际上调用fabric-client/lib/utils.js的 newKeyValueStore方法。
// Provide a Promise-based keyValueStore for couchdb, etc.
module.exports.newKeyValueStore = function(options) {
// initialize the correct KeyValueStore
var kvsEnv = this.getConfigSetting('key-value-store');
var store = require(kvsEnv);
return Promise.resolve(new store(options));
};此处， 程序首先从获取key-value-store的配置， 然后动态加载该模块， 然后返回Promise。可以看出， SDK提供了不同的KeyvalueStore实现， 默认为FileKeyValueStore实现， fabric-client/config/default.json中指定。
我们看default.json文件
{
...
"key-value-store": "fabric-client/lib/impl/FileKeyValueStore.js",
"certificate-authority-client": "fabric-ca-client",
"nonce-size" : 24,
...
}在fabric-client/lib/impl下可以看到， SDK提供了2种不同的实现：
FileKeyValueStore , CouchDBKeyValueStore.
我们看FileKeyValueStore的实现。在FileKeyValueStore的构造函数中， 有这么一段：
// Create the keyValStore instance
super();
var self = this;
this._dir = options.path;
return new Promise(function (resolve, reject) {
fs.mkdirs(self._dir, function (err) {
if (err) {
logger.error('constructor, error creating directory, code: %s' , err.code);
return reject(err);
}
return resolve(self);
});
});这一步执行后， 生成上面指定的hfc-key-store目录。 在看 FileKeyValueStore, 实际上实现了 setKey(name, value) 和 getValue(name) 方法。
上面步骤执行成功后， 拿到KeyValueStore对象，然后执行一下操作:
// 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);
var tlsOptions = {
trustedRoots: [],
verify: false
};
// be sure to change the http to https when the CA is running TLS enabled
fabric_ca_client = new Fabric_CA_Client('http://localhost:7054', tlsOptions , 'ca.example.com', crypto_suite);
// first check to see if the admin is already enrolled
return fabric_client.getUserContext('admin', true);1 生成CrytoKeyStore, 用来存储用户的密钥和用户的证书（状态)。
var crypto_store = Fabric_Client.newCryptoKeyStore({path: store_path});这里调用的是BaseClient.js的方法：
static newCryptoKeyStore(KVSImplClass, opts) {
return sdkUtils.newCryptoKeyStore(KVSImplClass, opts);
}这里调用util.js中的方法
module.exports.newCryptoKeyStore = function(KVSImplClass, opts) {
// this function supports skipping any of the arguments such that it can be called in any of the following fashions:
// - newCryptoKeyStore(CouchDBKeyValueStore, {name: 'member_db', url: 'http://localhost:5984'})
// - newCryptoKeyStore({path: '/tmp/app-state-store'})
// - newCryptoKeyStore()
return new CryptoKeyStore(KVSImplClass, opts);
};2 生成CryptoSuite
var crypto_suite = Fabric_Client.newCryptoSuite(); crypto_suite.setCryptoKeyStore(crypto_store);
3 指定 fabric_client的StateStore 和 CryptoSuite
fabric_client.setStateStore(state_store); fabric_client.setCryptoSuite(crypto_suite);
4 连接到Fabric CA
var tlsOptions = {
trustedRoots: [],
verify: false
};
// be sure to change the http to https when the CA is running TLS enabled
fabric_ca_client = new Fabric_CA_Client('http://localhost:7054', tlsOptions , 'ca.example.com', crypto_suite);5 检查admin是否enroll
fabric_client.getUserContext('admin', true);这一步返回一个User对象。true用于检测是否持久化。
同样看代码：
if (user_from_store && user_from_store.isEnrolled()) {
console.log('Successfully loaded admin from persistence');
admin_user = user_from_store;
return null;
} else {
// need to enroll it with CA server
return fabric_ca_client.enroll({
enrollmentID: 'admin',
enrollmentSecret: 'adminpw'
}).then((enrollment) => {
console.log('Successfully enrolled admin user "admin"');
return fabric_client.createUser(
{username: 'admin',
mspid: 'Org1MSP',
cryptoContent: { privateKeyPEM: enrollment.key.toBytes(), signedCertPEM: enrollment.certificate }
});
}).then((user) => {
admin_user = user;
return fabric_client.setUserContext(admin_user);
}).catch((err) => {
console.error('Failed to enroll and persist admin. Error: ' + err.stack ? err.stack : err);
throw new Error('Failed to enroll admin');
});
}这里检测User对象是否已经reroll, 否则先reroll, 然后register用户。
1 检测用户状态
if (user_from_store && user_from_store.isEnrolled()) {
console.log('Successfully loaded admin from persistence');
admin_user = user_from_store;
return null;
}这里User的API文档见：Hyperledger Fabric SDK for node.js Class: User 。
如果检测到用户已经reroll, 则说明当前用户已经reroll, 并且证书有效， 可以使用此证书进行后续操作， 否则需要注册用户。
2 reroll
return fabric_ca_client.enroll({
enrollmentID: 'admin',
enrollmentSecret: 'adminpw'
}).then((enrollment) => {
//
});此处的admin用户为配置文件中的启动用户，或者说是引导用户身份。或者应该是注册的具有相关权限的用户。
这一步执行后， 在hfc-key-store目录下产生af37da4c94057cd98f288a671703d346c7a79a79acd28ea8de7bf03cf04baf36-priv 文件， 内容为：
ThinkPad-L430:/opt/fabric-samples/fabcar$ ls hfc-key-store/ af37da4c94057cd98f288a671703d346c7a79a79acd28ea8de7bf03cf04baf36-priv ThinkPad-L430:/opt/fabric-samples/fabcar$ cat hfc-key-store/af37da4c94057cd98f288a671703d346c7a79a79acd28ea8de7bf03cf04baf36-priv -----BEGIN PRIVATE KEY----- MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgBqYfrwZerZFT2MU4 Dl5uyQxX2KyPzFu0ZUN14NDlMBuhRANCAARgBxgXvWsvWIPoxA8R1G+2A2D6YGtE NmE2ZTAeNXHJ+fWzitjOLrwaHKwl42/9sXfAaQP3WWYcEdSKicNrXTH3 -----END PRIVATE KEY-----
并且返回的enrollment对象内容为：
{ key:
ECDSA_KEY {
_key:
{ type: 'EC',
isPrivate: true,
isPublic: false,
getBigRandom: [Function],
setNamedCurve: [Function],
setPrivateKeyHex: [Function],
setPublicKeyHex: [Function],
getPublicKeyXYHex: [Function],
getShortNISTPCurveName: [Function],
generateKeyPairHex: [Function],
signWithMessageHash: [Function],
signHex: [Function],
sign: [Function],
verifyWithMessageHash: [Function],
verifyHex: [Function],
verify: [Function],
verifyRaw: [Function],
serializeSig: [Function],
parseSig: [Function],
parseSigCompact: [Function],
readPKCS5PrvKeyHex: [Function],
readPKCS8PrvKeyHex: [Function],
readPKCS8PubKeyHex: [Function],
readCertPubKeyHex: [Function],
curveName: 'secp256r1',
ecparams: [Object],
prvKeyHex: '06a61faf065ead9153d8c5380e5e6ec90c57d8ac8fcc5bb4654375e0d0e5301b',
pubKeyHex: '0460071817bd6b2f5883e8c40f11d46fb60360fa606b4436613665301e3571c9f9f5b38ad8ce2ebc1a1cac25e36ffdb177c06903f759661c11d48a89c36b5d31f7' } },
certificate: '-----BEGIN CERTIFICATE-----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\n8KVd0T9j8mlU7Sj3T7k=\n-----END CERTIFICATE-----\n',
rootCertificate: '-----BEGIN CERTIFICATE-----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\n56GY03W/ZiZY6Zg=\n-----END CERTIFICATE-----\n' }3 register
fabric_client.createUser(
{username: 'admin',
mspid: 'Org1MSP',
cryptoContent: { privateKeyPEM: enrollment.key.toBytes(), signedCertPEM: enrollment.certificate }
});
}).then((user) => {
//
});执行结果：
ThinkPad-L430:/opt/fabric-samples/fabcar$ ls hfc-key-store/
2124ac635ac52a4c5d13c32812768ebe6837ae288bfa351c3712b9160f502214-priv admin
2124ac635ac52a4c5d13c32812768ebe6837ae288bfa351c3712b9160f502214-pub
ThinkPad-L430:/opt/fabric-samples/fabcar$ cat hfc-key-store/2124ac635ac52a4c5d13c32812768ebe6837ae288bfa351c3712b9160f502214-pub
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEnUNKr708UFaMWRHbdfcM8oTW130U
H/u7X3tH+/88RQR5O8sA5EyKsMMi5OgrhwQkRbYZ8FUIiZuHRZUxL9as1w==
-----END PUBLIC KEY-----
ThinkPad-L430:/opt/fabric-samples/fabcar$ cat hfc-key-store/admin
{"name":"admin","mspid":"Org1MSP","roles":null,"affiliation":"","enrollmentSecret":"","enrollment":{"signingIdentity":"2124ac635ac52a4c5d13c32812768ebe6837ae288bfa351c3712b9160f502214","identity":{"certificate":"-----BEGIN CERTIFICATE-----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\nnPmYhhiKe9DqeDw3H3ku\n-----END CERTIFICATE-----\n"}}}这一步执行成功后， 需要设置fabric_client中的当前用户。
fabric_client.setUserContext(admin_user);
此刻， reroll整个过程完成。
以上是“Hyperledger Fabric中通过SDK和Hyperledger Fabric Blockchain交互的示例分析”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注亿速云行业资讯频道！
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