Hyperledger Fabric架構及Java SDK實現(xiàn)

Hyperledger Fabric 整理體系：

運行時架構

運行時架構

各項解釋如下：

  • APP：代表一個客戶端或者SDK，作用是創(chuàng)建交易并獲取到足夠的背書之后向Orderer排序服務節(jié)點提交交易請求。（peer和orderer提供了gRPC遠程訪問接口，供客戶端調用）
  • CA：負責對網絡中所有證書進行管理，提供標準的KPI服務
  • MSP：為客戶端和peer提供證書的系統(tǒng)抽象組件
  • Channel：通道提供了一種通訊機制，將peers和orderer連接在一起，形成一個具有保密性的通訊鏈路；將一個大網絡分割成不同私有子網，進行數(shù)據(jù)隔離
  • Orderer：對客戶端提交的交易請求進行排序，之后生成區(qū)塊廣播給通道內所有peer節(jié)點
  • Org1：代表聯(lián)盟中的某-組織
  • Peer：表示組織中的節(jié)點；peer節(jié)點以區(qū)塊的形式從orderer排序服務節(jié)點接收有序狀態(tài)更新，維護狀態(tài)和賬本。fabric中Peer節(jié)點可劃分如下：
    1. Endorsing Peer：根據(jù)指定的策略調用智能合約，對結果進行背書，返回提案相應到客戶端
    2. Committing Peer：驗證數(shù)據(jù)并保存到賬本中
    3. Anchor Peer：跨組織通訊
    4. Leading Peer：做為組織內所有節(jié)點的代表連接到Orderer排序服務節(jié)點，將從排序服務節(jié)點接收到的批量區(qū)塊廣播給組織內的其他節(jié)點
  • Chaincode：鏈碼，部署在fabric的網絡節(jié)點中，獨立運行在具有安全特性的受保護容器中，以gRPC協(xié)議與相應Peer節(jié)點進行通訊，提供相應的API與賬本數(shù)據(jù)進行交互
  • Ledger：有排序服務構建的一個全部有序的交易哈希鏈塊，保存在所有的Peer節(jié)點中。

?Java SDK提供了一種執(zhí)行用戶鏈碼，查詢塊數(shù)據(jù)，在通道進行交易及模擬事件的方式。
?此模式下，區(qū)塊鏈網絡由兩個組織，每個組織包含兩個結點，和一個order服務；將展示怎樣創(chuàng)建和初始化通道，安裝和部署鏈碼，和執(zhí)行調用和查詢操作。


fabric network
基本原理

?在fabric區(qū)塊鏈中，應用通過結點RPC協(xié)議接口訪問鏈碼。


基本流程

?類似于Shim API對鏈碼通訊協(xié)議的封裝，JavaSDK提供了對結點RPC協(xié)議接口封裝，其入口類為HFClient；對鏈碼的交易和查詢操作則封裝在channel類中。


基本流程 - 類說明
簡單實例

  • 實現(xiàn)User接口
    ?HFClient訪問fabric網絡身份使用User接口實現(xiàn)。
    ?一個用戶的身份由它的證書來標識的，同時交易還需要證書對應的私鑰，因此LocalUser的核心邏輯就是利用指定的證書和私鑰PEM文件滿足User接口的要求。

    User類實現(xiàn)

  • 訪問鏈碼
    ?創(chuàng)建HFClient實例，然后獲取通道對象，就可以查詢鏈碼或者提交鏈碼交易。

命令行操作： hyperledger fabric byfn up詳解
代碼具體實現(xiàn)
  • 運行fabric-samples中fabcar，創(chuàng)建區(qū)塊鏈網絡
  • 新建Java工程，引入fabric-gateway-java，實現(xiàn)具體實現(xiàn)
    pom.xml
    <repositories>
        <repository>
            <id>oss-sonatype</id>
            <name>OSS Sonatype</name>
            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>org.hyperledger.fabric</groupId>
            <artifactId>fabric-gateway-java</artifactId>
            <version>1.4.1-SNAPSHOT</version>
        </dependency>
    </dependencies>

加入Admins角色：

public class EnrollAdmin {

    static {
        System.setProperty("org.hyperledger.fabric.sdk.service_discovery.as_localhost", "true");
    }

    public static void main(String[] args) throws Exception {

        // Create a CA client for interacting with the CA.
        Properties props = new Properties();
        props.put("pemFile",
            "/Users/macserver/Documents/BlockChain/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/ca/ca.org1.example.com-cert.pem");
        props.put("allowAllHostNames", "true");
        HFCAClient caClient = HFCAClient.createNewInstance("https://localhost:7054", props);
        CryptoSuite cryptoSuite = CryptoSuiteFactory.getDefault().getCryptoSuite();
        caClient.setCryptoSuite(cryptoSuite);

        // Create a wallet for managing identities
        Wallet wallet = Wallet.createFileSystemWallet(Paths.get("wallet"));

        // Check to see if we've already enrolled the admin user.
        boolean adminExists = wallet.exists("admin");
        if (adminExists) {
            System.out.println("An identity for the admin user \"admin\" already exists in the wallet");
            return;
        }

        // Enroll the admin user, and import the new identity into the wallet.
        final EnrollmentRequest enrollmentRequestTLS = new EnrollmentRequest();
        enrollmentRequestTLS.addHost("localhost");
        enrollmentRequestTLS.setProfile("tls");
        Enrollment enrollment = caClient.enroll("admin", "adminpw", enrollmentRequestTLS);
        Identity user = Identity.createIdentity("Org1MSP", enrollment.getCert(), enrollment.getKey());
        wallet.put("admin", user);
        System.out.println("Successfully enrolled user \"admin\" and imported it into the wallet");
    }
}

加入user1角色：

public class RegisterUser {

    static {
        System.setProperty("org.hyperledger.fabric.sdk.service_discovery.as_localhost", "true");
    }

    public static void main(String[] args) throws Exception {

        // Create a CA client for interacting with the CA.
        Properties props = new Properties();
        props.put("pemFile",
            "/Users/macserver/Documents/BlockChain/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/ca/ca.org1.example.com-cert.pem");
        props.put("allowAllHostNames", "true");
        HFCAClient caClient = HFCAClient.createNewInstance("https://localhost:7054", props);
        CryptoSuite cryptoSuite = CryptoSuiteFactory.getDefault().getCryptoSuite();
        caClient.setCryptoSuite(cryptoSuite);

        // Create a wallet for managing identities
        Wallet wallet = Wallet.createFileSystemWallet(Paths.get("wallet"));

        // Check to see if we've already enrolled the user.
        boolean userExists = wallet.exists("user1");
        if (userExists) {
            System.out.println("An identity for the user \"user1\" already exists in the wallet");
            return;
        }

        userExists = wallet.exists("admin");
        if (!userExists) {
            System.out.println("\"admin\" needs to be enrolled and added to the wallet first");
            return;
        }

        Identity adminIdentity = wallet.get("admin");
        User admin = new User() {

            @Override
            public String getName() {
                return "admin";
            }

            @Override
            public Set<String> getRoles() {
                return null;
            }

            @Override
            public String getAccount() {
                return null;
            }

            @Override
            public String getAffiliation() {
                return "org1.department1";
            }

            @Override
            public Enrollment getEnrollment() {
                return new Enrollment() {

                    @Override
                    public PrivateKey getKey() {
                        return adminIdentity.getPrivateKey();
                    }

                    @Override
                    public String getCert() {
                        return adminIdentity.getCertificate();
                    }
                };
            }

            @Override
            public String getMspId() {
                return "Org1MSP";
            }

        };

        // Register the user, enroll the user, and import the new identity into the wallet.
        RegistrationRequest registrationRequest = new RegistrationRequest("user1");
        registrationRequest.setAffiliation("org1.department1");
        registrationRequest.setEnrollmentID("user1");
        String enrollmentSecret = caClient.register(registrationRequest, admin);
        Enrollment enrollment = caClient.enroll("user1", enrollmentSecret);
        Identity user = Identity.createIdentity("Org1MSP", enrollment.getCert(), enrollment.getKey());
        wallet.put("user1", user);
        System.out.println("Successfully enrolled user \"user1\" and imported it into the wallet");
    }

}

客戶端：查詢及添加新數(shù)據(jù)

public class ClientApp {

    static {
        System.setProperty("org.hyperledger.fabric.sdk.service_discovery.as_localhost", "true");
    }

    public static void main(String[] args) throws Exception {
        // Load a file system based wallet for managing identities.
        Path walletPath = Paths.get("wallet");
        Wallet wallet = Wallet.createFileSystemWallet(walletPath);

        // load a CCP
        Path networkConfigPath = Paths.get("/Users/macserver/Documents/BlockChain/src/github.com/hyperledger/fabric-samples/fabcar", "..", "first-network", "connection-org1.yaml");

        Gateway.Builder builder = Gateway.createBuilder();
        builder.identity(wallet, "user1").networkConfig(networkConfigPath).discovery(true);

        // create a gateway connection
        try (Gateway gateway = builder.connect()) {

            // get the network and contract
            Network network = gateway.getNetwork("mychannel");
            Contract contract = network.getContract("fabcar");

            byte[] result;

            result = contract.evaluateTransaction("queryAllCars");
            System.out.println(new String(result));

            contract.submitTransaction("createCar", "CAR10", "VW", "Polo", "Grey", "Mary");

            result = contract.evaluateTransaction("queryCar", "CAR10");
            System.out.println(new String(result));

            contract.submitTransaction("changeCarOwner", "CAR10", "Archie");

            result = contract.evaluateTransaction("queryCar", "CAR10");
            System.out.println(new String(result));
        }
    }

}
實現(xiàn)方式 二

?如果跳過gateway，直接使用fabric-sdk-java，數(shù)據(jù)查詢-實現(xiàn)代碼如下：

private static void queryAllCars() throws Exception {
        HFClient hfClient = HFClient.createNewInstance();

        CryptoSuite cryptoSuite = CryptoSuiteFactory.getDefault().getCryptoSuite();
        hfClient.setCryptoSuite(cryptoSuite);

        Enrollment enrollment = new X509Enrollment(getPrivateKey(Paths.get("wallet/user1/user1-priv")), getCertificate(certificate_user1));
        User user = new User() {
            @Override
            public String getName() {
                return "gateway";
            }

            @Override
            public Set<String> getRoles() {
                return Collections.emptySet();
            }

            @Override
            public String getAccount() {
                return "";
            }

            @Override
            public String getAffiliation() {
                return "";
            }

            @Override
            public Enrollment getEnrollment() {
                return enrollment;
            }

            @Override
            public String getMspId() {
                return "Org1MSP";
            }
        };

        hfClient.setUserContext(user);

        NetworkConfig networkConfig = NetworkConfig.fromYamlFile(new File(path + "first-network/connection-org1.yaml"));

        Channel channel = hfClient.newChannel("mychannel");

        List<String> peerNames = networkConfig.getClientOrganization().getPeerNames();
        for (String name : peerNames) {
            String url = networkConfig.getPeerUrl(name);
            Properties props = networkConfig.getPeerProperties(name);
            System.err.println("xxxxxxxxx：" + name + "..." + url);
            Peer peer = hfClient.newPeer(name, url, props);

            Channel.PeerOptions peerOptions = Channel.PeerOptions.createPeerOptions().setPeerRoles(EnumSet.allOf(Peer.PeerRole.class));
            channel.addPeer(peer, peerOptions);
        }

        channel.initialize();


        QueryByChaincodeRequest request = QueryByChaincodeRequest.newInstance(user);

        request.setChaincodeID(getChaincodeId("fabcar"));
        request.setFcn("queryAllCars");
        request.setArgs("");

        Collection<ProposalResponse> responses = channel.queryByChaincode(request, Collections.singletonList(channel.getPeers().iterator().next()));
        ProposalResponse response = responses.iterator().next();
        byte[] bytes = response.getChaincodeActionResponsePayload();

        System.err.println("xxxxxxx：" + new String(bytes));
    }

    private static String getCertificate(String certificate) {
        BufferedReader certReader = new BufferedReader(new StringReader(certificate));
        return certReader.lines().collect(Collectors.joining("\n", "", "\n"));
    }

    private static PrivateKey getPrivateKey(Path pemFile) {
        try {
            PEMParser parser = new PEMParser(Files.newBufferedReader(pemFile));
            Object key = parser.readObject();
            JcaPEMKeyConverter converter = new JcaPEMKeyConverter();
            return converter.getPrivateKey((PrivateKeyInfo) key);
        } catch (IOException e) {
            System.err.println("private key 獲取失敗");
            return null;
        }
    }

    private static ChaincodeID getChaincodeId(String chaincodeId) {
        return ChaincodeID.newBuilder()
                .setName(chaincodeId)
                .build();
    }
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