Hyperledger Fabric 2. X custom smart contract

One 、 explain

In order to continuously update the information , And manage the ledger （ Write transaction , Make inquiries, etc ）, The blockchain network introduces smart contracts to access and control the ledger ; The smart contract is in Fabric Referred to as Chain code , It is the business logic of blockchain application .

This article shares how to use Java Language development smart contract , And the installation and use of the contract .

 

Two 、 Environmental preparation

1、 Deploy well Fabric The test network , According to the previous article 《Hyperledger Fabric 2.x Environment building 》 The contents of the are subject to section 1 to 5 Step

-  Start two  peer  Node and a  orderer  node -  Create good  mychannel  passageway 

2、 Configure the execution command in the environment variable (bin)、 To configure (config) And MSP Path to folder ： perform vim /etc/profile Add the following ：

export FABRIC_PATH=/opt/gopath/src/github.com/hyperledger/fabric-samplesexport FABRIC_CFG_PATH=${FABRIC_PATH}/config/export MSP_PATH=${FABRIC_PATH}/test-network/organizationsexport CORE_PEER_TLS_ENABLED=trueexport PATH=${FABRIC_PATH}/bin:$PATH

FABRIC_PATH The path is modified according to the actual situation .

 

3、 ... and 、 Download contract code

gitee：https://gitee.com/zlt2000_admin/my-fabric-chaincode-java

github：https://github.com/zlt2000/my-fabric-chaincode-java

 

Four 、 Code parsing

stay Fabric 2.x The contract writing method after the version is slightly different from the old version , Need to achieve ContractInterface Interface , Here is an official explanation ：

All chaincode implementations must extend the abstract class ChaincodeBase. It is possible to implement chaincode by extending ChaincodeBase directly however new projects should implement org.hyperledger.fabric.contract.ContractInterface and use the contract programming model instead.

4.1. pom.xml file

Configure remote warehouse

<repositories>		<repository>				<id>central</id>				<url>http://maven.aliyun.com/nexus/content/groups/public/</url>				<releases>						<enabled>true</enabled>				</releases>				<snapshots>						<enabled>false</enabled>				</snapshots>		</repository>		<repository>				<id>jitpack.io</id>				<url>https://www.jitpack.io</url>		</repository>		<repository>				<id>artifactory</id>				<url>https://hyperledger.jfrog.io/hyperledger/fabric-maven</url>		</repository></repositories>

 

Dependent contract sdk

<dependency>		<groupId>org.hyperledger.fabric-chaincode-java</groupId>		<artifactId>fabric-chaincode-shim</artifactId>		<version>${fabric-chaincode-java.version}</version></dependency>

 

Through plug-ins maven-shade-plugin Appoint mainClass by org.hyperledger.fabric.contract.ContractRouter

The new version of all contracts mainClass All for org.hyperledger.fabric.contract.ContractRouter

<build>		<sourceDirectory>src/main/java</sourceDirectory>		<plugins>				<plugin>						<artifactId>maven-compiler-plugin</artifactId>						<version>3.1</version>						<configuration>								<source>${java.version}</source>								<target>${java.version}</target>						</configuration>				</plugin>				<plugin>						<groupId>org.apache.maven.plugins</groupId>						<artifactId>maven-shade-plugin</artifactId>						<version>3.1.0</version>						<executions>								<execution>										<phase>package</phase>										<goals>												<goal>shade</goal>										</goals>										<configuration>												<finalName>chaincode</finalName>												<transformers>														<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">																<mainClass>org.hyperledger.fabric.contract.ContractRouter</mainClass>														</transformer>												</transformers>												<filters>														<filter>																<!-- filter out signature files from signed dependencies, else repackaging fails with security ex -->																<artifact>*:*</artifact>																<excludes>																		<exclude>META-INF/*.SF</exclude>																		<exclude>META-INF/*.DSA</exclude>																		<exclude>META-INF/*.RSA</exclude>																</excludes>														</filter>												</filters>										</configuration>								</execution>						</executions>				</plugin>		</plugins></build>

 

4.2. model

Create the data object of the contract User Use @DataType Annotation marks , Define three fields userId、name、money Use @Property Annotation marks ：

@DataTypepublic class User {    @Property    private final String userId;    @Property    private final String name;    @Property    private final double money;    public User(final String userId, final String name, final double money) {        this.userId = userId;        this.name = name;        this.money = money;    }    @Override    public boolean equals(final Object obj) {        if (this == obj) {            return true;        }        if ((obj == null) || (getClass() != obj.getClass())) {            return false;        }        User other = (User) obj;        return Objects.deepEquals(                new String[] {getUserId(), getName()},                new String[] {other.getUserId(), other.getName()})                &&                Objects.deepEquals(                        new double[] {getMoney()},                        new double[] {other.getMoney()});    }    @Override    public int hashCode() {        return Objects.hash(getUserId(), getName(), getMoney());    }    @Override    public String toString() {        return JSON.toJSONString(this);    }    public String getUserId() {        return userId;    }    public String getName() {        return name;    }    public double getMoney() {        return money;    }}

 

4.3. Contract logic

1. Contract use @Contract And @Default Annotation marks , And implement ContractInterface Interface
2. Use of contract method @Transaction Annotation marks

   Transaction.TYPE.SUBMIT by Write transaction Transaction.TYPE.EVALUATE by Inquire about

3. contain 3 There are two trading methods ：init、addUser、transfer
4. contain 2 A query method ：getUser、queryAll

@Contract(name = "mycc")@Defaultpublic class MyAssetChaincode implements ContractInterface {    public  MyAssetChaincode() {}    /**     *  initialization 3 Bar record      */    @Transaction(intent = Transaction.TYPE.SUBMIT)    public void init(final Context ctx) {        addUser(ctx, "1", "zlt",100D);        addUser(ctx, "2", "admin",200D);        addUser(ctx, "3", "guest",300D);    }    /**     *  New users      */    @Transaction(intent = Transaction.TYPE.SUBMIT)    public User addUser(final Context ctx, final String userId, final String name, final double money) {        ChaincodeStub stub = ctx.getStub();        User user = new User(userId, name, money);        String userJson = JSON.toJSONString(user);        stub.putStringState(userId, userJson);        return user;    }    /**     *  Querying a user      */    @Transaction(intent = Transaction.TYPE.EVALUATE)    public User getUser(final Context ctx, final String userId) {        ChaincodeStub stub = ctx.getStub();        String userJSON = stub.getStringState(userId);        if (userJSON == null || userJSON.isEmpty()) {            String errorMessage = String.format("User %s does not exist", userId);            throw new ChaincodeException(errorMessage);        }        User user = JSON.parseObject(userJSON, User.class);        return user;    }    /**     *  Query all users      */    @Transaction(intent = Transaction.TYPE.EVALUATE)    public String queryAll(final Context ctx) {        ChaincodeStub stub = ctx.getStub();        List<User> userList = new ArrayList<>();        QueryResultsIterator<KeyValue> results = stub.getStateByRange("", "");        for (KeyValue result: results) {            User user = JSON.parseObject(result.getStringValue(), User.class);            System.out.println(user);            userList.add(user);        }        return JSON.toJSONString(userList);    }    /**     *  Transfer accounts      * @param sourceId  Source user id     * @param targetId  Target users id     * @param money  amount of money      */    @Transaction(intent = Transaction.TYPE.SUBMIT)    public void transfer(final Context ctx, final String sourceId, final String targetId, final double money) {        ChaincodeStub stub = ctx.getStub();        User sourceUser = getUser(ctx, sourceId);        User targetUser = getUser(ctx, targetId);        if (sourceUser.getMoney() < money) {            String errorMessage = String.format("The balance of user %s is insufficient", sourceId);            throw new ChaincodeException(errorMessage);        }        User newSourceUser = new User(sourceUser.getUserId(), sourceUser.getName(), sourceUser.getMoney() - money);        User newTargetUser = new User(targetUser.getUserId(), targetUser.getName(), targetUser.getMoney() + money);        stub.putStringState(sourceId, JSON.toJSONString(newSourceUser));        stub.putStringState(targetId, JSON.toJSONString(newTargetUser));    }}

 

5、 ... and 、 Package contract code

Package the contract source code into a compressed file , For subsequent installation ：

peer lifecycle chaincode package mycc.tar.gz --path /opt/app/my-fabric-chaincode-java --lang java --label mycc

 

6、 ... and 、 Installation contract

In the specified peer Install chain code on node , The following are the installation of two mechanisms .

6.1. For the agency peer0.org1 Installation contract

Execute the following command , Set up peer0.org1 Environmental Science ：

export CORE_PEER_LOCALMSPID="Org1MSP"export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crtexport CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org1.example.com/users/[email protected]/mspexport CORE_PEER_ADDRESS=localhost:7051

Perform the following installation ：

peer lifecycle chaincode install mycc.tar.gz

Return to... After success ：

2022-02-09 22:09:13.498 EST 0001 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Installed remotely: response:<status:200 payload:"\nEmycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae\022\004mycc" > 2022-02-09 22:09:13.498 EST 0002 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Chaincode code package identifier: mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae

 

6.2. For the agency peer0.org2 Installation contract

Execute the following command , Set up peer0.org2 Environmental Science ：

export CORE_PEER_LOCALMSPID="Org2MSP"export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crtexport CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org2.example.com/users/[email protected]/mspexport CORE_PEER_ADDRESS=localhost:9051

Perform the following installation ：

peer lifecycle chaincode install mycc.tar.gz

Return to... After success ：

2022-02-09 22:14:14.862 EST 0001 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Installed remotely: response:<status:200 payload:"\nEmycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae\022\004mycc" > 2022-02-09 22:14:14.862 EST 0002 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Chaincode code package identifier: mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae

Check the list of installed contracts ：

peer lifecycle chaincode queryinstalled

Return the of the contract Package ID And Label：

Installed chaincodes on peer:Package ID: mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae, Label: mycc

 

7、 ... and 、 Approve the contract

When the contract is installed , It is only allowed to use after the approval and agreement of the organization .  

7.1. For the agency peer0.org1 Approve contract definitions

Execute the following command , Set up peer0.org1 Environmental Science ：

export CORE_PEER_LOCALMSPID="Org1MSP"export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crtexport CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org1.example.com/users/[email protected]/mspexport CORE_PEER_ADDRESS=localhost:7051

Execute the following command to approve the contract ：

peer lifecycle chaincode approveformyorg \  -o localhost:7050 \  --ordererTLSHostnameOverride orderer.example.com \  --tls   --cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \  --channelID mychannel \  --name mycc \  --version 1.0 \  --package-id mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae \  --sequence 1

package-id The value of is modified according to the actual situation .

Return to... After success ：

2022-02-09 22:22:38.403 EST 0001 INFO [chaincodeCmd] ClientWait -> txid [2531db2811945a641947000cb15cfd19e0b72da594dfba994f5f79b6bc51bce2] committed with status (VALID) at localhost:7051

 

7.2. For the agency peer0.org2 Approve contract definitions

Execute the following command , Set up peer0.org2 Environmental Science ：

export CORE_PEER_LOCALMSPID="Org2MSP"export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crtexport CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org2.example.com/users/[email protected]/mspexport CORE_PEER_ADDRESS=localhost:9051

Execute the following command to approve the contract ：

peer lifecycle chaincode approveformyorg \  -o localhost:7050 \  --ordererTLSHostnameOverride orderer.example.com \  --tls \  --cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \  --channelID mychannel \  --name mycc \  --version 1.0 \  --package-id mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae \  --sequence 1

package-id The value of is modified according to the actual situation .

Return to... After success ：

2022-02-09 22:22:47.711 EST 0001 INFO [chaincodeCmd] ClientWait -> txid [796a1e0a735e69425bcd5911bdf4b2a8003bbac977c5e60c769f84da6b86ef86] committed with status (VALID) at localhost:9051

 

7.3. Contract submission for inspection

Check the approval of the contract , Can I submit to the channel ：

peer lifecycle chaincode checkcommitreadiness --channelID mychannel --name mycc --version 1.0 --sequence 1 --output json

return ：

{	"approvals": {		"Org1MSP": true,		"Org2MSP": true	}}

representative Org1 and Org2 All approved

 

8、 ... and 、 Submit contract

Execute the following command , Submit the contract to the channel ：

peer lifecycle chaincode commit \  -o localhost:7050 \  --ordererTLSHostnameOverride orderer.example.com \  --tls \  --cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \  --channelID mychannel \  --name mycc \  --peerAddresses localhost:7051 \  --tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt \  --peerAddresses localhost:9051 \  --tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt \  --version 1.0 \  --sequence 1

Return to... After success ：

2022-02-09 22:22:57.445 EST 0001 INFO [chaincodeCmd] ClientWait -> txid [97ded758675113b9339dc9b378a13c0790ea3780855bb8f651758bfb007fc1ec] committed with status (VALID) at localhost:70512022-02-09 22:22:57.456 EST 0002 INFO [chaincodeCmd] ClientWait -> txid [97ded758675113b9339dc9b378a13c0790ea3780855bb8f651758bfb007fc1ec] committed with status (VALID) at localhost:9051

View the submitted contracts on the channel ：

peer lifecycle chaincode querycommitted --channelID mychannel --name mycc --output json

return ：

{	"sequence": 1,	"version": "1.0",	"endorsement_plugin": "escc",	"validation_plugin": "vscc",	"validation_parameter": "EiAvQ2hhbm5lbC9BcHBsaWNhdGlvbi9FbmRvcnNlbWVudA==",	"collections": {},	"approvals": {		"Org1MSP": true,		"Org2MSP": true	}}

 

Nine 、 Test smart contracts

1. Transaction data usage peer chaincode invoke [flags] command , The order will attempt to submit an endorsed transaction to the network .
2. Query data using peer chaincode query [flags], This command does not generate a transaction .

because invoke More parameters required by the command , So let's create a script command first . perform vim invoke.sh Add the following ：

peer chaincode invoke -o localhost:7050 \  --ordererTLSHostnameOverride orderer.example.com \  --tls \  --cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \  -C mychannel \  -n mycc \  --peerAddresses localhost:7051 \  --tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt \  --peerAddresses localhost:9051 \  --tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt \  -c ${1}

9.1. Initialize the ledger

Execute the following command , Call the contract init Method initialization 3 A ledger record ：

sh invoke.sh '{"function":"init","Args":[]}'

 

9.2. Query data

You need to connect one of them peer Node to query data

Execute the following command , Set up peer0.org1 Environmental Science ：

export CORE_PEER_LOCALMSPID="Org1MSP"export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crtexport CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org1.example.com/users/[email protected]/mspexport CORE_PEER_ADDRESS=localhost:7051

Execute the following command , call queryAll Method , Query all the data ：

peer chaincode query -C mychannel -n mycc -c '{"Args":["queryAll"]}'

Go back to 3 An array of data ：

[{"money":100.0,"name":"zlt","userId":"1"},{"money":200.0,"name":"admin","userId":"2"},{"money":300.0,"name":"guest","userId":"3"}]

 

Execute the following command , call getUser Methods the incoming 1 Parameters , Query individual data ：

peer chaincode query -C mychannel -n mycc -c '{"Args":["getUser", "1"]}'

Go back to id by 1 The data of ：

{"money":100,"name":"zlt","userId":"1"}

 

9.3. The new data

Execute the following command , call addUser Method , Add a new one id by 4 The record of ：

sh invoke.sh '{"function":"addUser","Args":["4","test","400"]}'

 

9.4. Transfer accounts

Execute the following command , call transfer Method , Transfer operations ：

sh invoke.sh '{"function":"transfer","Args":["4","1","400"]}'

After the transfer is successful , Use the query command to view ：

peer chaincode query -C mychannel -n mycc -c '{"Args":["queryAll"]}'

 

Code scanning, attention, surprise ！