• 【区块链技术与应用】（八）

    https://blog.csdn.net/lakersssss24/article/details/125762826?spm=1001.2014.3001.5501
    https://blog.csdn.net/lakersssss24/article/details/126434147
    https://blog.csdn.net/lakersssss24/article/details/126671408?spm=1001.2101.3001.6650.3&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7ERate-3-126671408-blog-126434147.pc_relevant_3mothn_strategy_and_data_recovery&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7ERate-3-126671408-blog-126434147.pc_relevant_3mothn_strategy_and_data_recovery&utm_relevant_index=4

    提前准备

    在这里插入图片描述

    sudo apt-get update  更新源 
sudo apt-get install ssh 安装远程客户端
sudo apt-get install curl 安装命令行工具
sudo apt-get install git 安装git
sudo apt-get install gcc 安装gcc
sudo apt-get install vim 安装vim文件编辑器
sudo apt-get install make 安装make
sudo apt-get install net-tools 安装网络工具
sudo apt-get install net-tools  安装mousepad 类似于windows的记事本

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    ./bootstrap.sh

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    https://teach.imcn.me/y2020/1146.html

    couchDB安装 https://blog.csdn.net/TU_Dresden/article/details/126864418

    请添加图片描述

    实验一

    network

    ./network.sh up

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    请添加图片描述
    请添加图片描述

    ./network.sh up createChannel -s couchdb

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    请添加图片描述

    ./network.sh deployCC -ccn basic -ccp ../asset-transfer-basic/chaincode-go -ccl go

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    export PATH=${PWD}/../bin:$PATH
export FABRIC_CFG_PATH=$PWD/../config/
export CORE_PEER_TLS_ENABLED=true
export CORE_PEER_LOCALMSPID="Org1MSP" 
export CORE_PEER_TLS_ROOTCERT_FILE=${PWD}/organizations/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt
export CORE_PEER_MSPCONFIGPATH=${PWD}/organizations/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
export CORE_PEER_ADDRESS=localhost:7051

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    peer chaincode invoke -o localhost:7050 --ordererTLSHostnameOverride orderer.example.com --tls --cafile "${PWD}/organizations/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem" -C mychannel -n basic --peerAddresses localhost:7051 --tlsRootCertFiles "${PWD}/organizations/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt" --peerAddresses localhost:9051 --tlsRootCertFiles "${PWD}/organizations/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt" -c '{"function":"InitLedger","Args":[""]}'

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    在这里插入图片描述
    restart

    ./network.sh up createChannel -ca -s couchdb



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    gin模板

    package main
 
import (
	"fmt"
	"github.com/gin-gonic/gin"
)
 
type Stu struct {
	Name string `form:"name"`
	Id   string `form:"id"`
	Age  string `form:"age"`
}
 
func main() {
	r := gin.Default()
	var stu Stu
	r1 := r.Group("/fabric2.4")
	r1.POST("/setstu", func(c *gin.Context) {
		//var stu Stu
		c.ShouldBind(&stu)
		c.JSON(200, stu)
		fmt.Println("stu:", stu)
	})
	r1.POST("/ok1", func(c *gin.Context) {
		c.JSON(200, "ok1")
	})
	r.Run(":8080") // 监听并在 0.0.0.0:8080 上启动服务
 
}

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    链码的只要功能部分：

    package chaincode
 
import (
	"encoding/json"
	"fmt"
 
	"github.com/hyperledger/fabric-contract-api-go/contractapi"
)
 
// SmartContract provides functions for managing an Asset
type SmartContract struct {
	contractapi.Contract
}
 
// Asset describes basic details of what makes up a simple asset
//Insert struct field in alphabetic order => to achieve determinism across languages
// golang keeps the order when marshal to json but doesn't order automatically
type Asset struct {
	AppraisedValue int    `json:"AppraisedValue"`
	Color          string `json:"Color"`
	ID             string `json:"ID"`
	Owner          string `json:"Owner"`
	Size           int    `json:"Size"`
}
 
// InitLedger adds a base set of assets to the ledger
func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface) error {
	assets := []Asset{
		{ID: "asset1", Color: "blue", Size: 5, Owner: "Tomoko", AppraisedValue: 300},
		{ID: "asset2", Color: "red", Size: 5, Owner: "Brad", AppraisedValue: 400},
		{ID: "asset3", Color: "green", Size: 10, Owner: "Jin Soo", AppraisedValue: 500},
		{ID: "asset4", Color: "yellow", Size: 10, Owner: "Max", AppraisedValue: 600},
		{ID: "asset5", Color: "black", Size: 15, Owner: "Adriana", AppraisedValue: 700},
		{ID: "asset6", Color: "white", Size: 15, Owner: "Michel", AppraisedValue: 800},
	}
 
	for _, asset := range assets {
		assetJSON, err := json.Marshal(asset)
		if err != nil {
			return err
		}
 
		err = ctx.GetStub().PutState(asset.ID, assetJSON)
		if err != nil {
			return fmt.Errorf("failed to put to world state. %v", err)
		}
	}
 
	return nil
}
 
// CreateAsset issues a new asset to the world state with given details.
func (s *SmartContract) CreateAsset(ctx contractapi.TransactionContextInterface, id string, color string, size int, owner string, appraisedValue int) error {
	exists, err := s.AssetExists(ctx, id)
	if err != nil {
		return err
	}
	if exists {
		return fmt.Errorf("the asset %s already exists", id)
	}
 
	asset := Asset{
		ID:             id,
		Color:          color,
		Size:           size,
		Owner:          owner,
		AppraisedValue: appraisedValue,
	}
	assetJSON, err := json.Marshal(asset)
	if err != nil {
		return err
	}
 
	return ctx.GetStub().PutState(id, assetJSON)
}
 
// ReadAsset returns the asset stored in the world state with given id.
func (s *SmartContract) ReadAsset(ctx contractapi.TransactionContextInterface, id string) (*Asset, error) {
	assetJSON, err := ctx.GetStub().GetState(id)
	if err != nil {
		return nil, fmt.Errorf("failed to read from world state: %v", err)
	}
	if assetJSON == nil {
		return nil, fmt.Errorf("the asset %s does not exist", id)
	}
 
	var asset Asset
	err = json.Unmarshal(assetJSON, &asset)
	if err != nil {
		return nil, err
	}
 
	return &asset, nil
}
 
// UpdateAsset updates an existing asset in the world state with provided parameters.
func (s *SmartContract) UpdateAsset(ctx contractapi.TransactionContextInterface, id string, color string, size int, owner string, appraisedValue int) error {
	exists, err := s.AssetExists(ctx, id)
	if err != nil {
		return err
	}
	if !exists {
		return fmt.Errorf("the asset %s does not exist", id)
	}
 
	// overwriting original asset with new asset
	asset := Asset{
		ID:             id,
		Color:          color,
		Size:           size,
		Owner:          owner,
		AppraisedValue: appraisedValue,
	}
	assetJSON, err := json.Marshal(asset)
	if err != nil {
		return err
	}
 
	return ctx.GetStub().PutState(id, assetJSON)
}
 
// DeleteAsset deletes an given asset from the world state.
func (s *SmartContract) DeleteAsset(ctx contractapi.TransactionContextInterface, id string) error {
	exists, err := s.AssetExists(ctx, id)
	if err != nil {
		return err
	}
	if !exists {
		return fmt.Errorf("the asset %s does not exist", id)
	}
 
	return ctx.GetStub().DelState(id)
}
 
// AssetExists returns true when asset with given ID exists in world state
func (s *SmartContract) AssetExists(ctx contractapi.TransactionContextInterface, id string) (bool, error) {
	assetJSON, err := ctx.GetStub().GetState(id)
	if err != nil {
		return false, fmt.Errorf("failed to read from world state: %v", err)
	}
 
	return assetJSON != nil, nil
}
 
// TransferAsset updates the owner field of asset with given id in world state, and returns the old owner.
func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, id string, newOwner string) (string, error) {
	asset, err := s.ReadAsset(ctx, id)
	if err != nil {
		return "", err
	}
 
	oldOwner := asset.Owner
	asset.Owner = newOwner
 
	assetJSON, err := json.Marshal(asset)
	if err != nil {
		return "", err
	}
 
	err = ctx.GetStub().PutState(id, assetJSON)
	if err != nil {
		return "", err
	}
 
	return oldOwner, nil
}
 
// GetAllAssets returns all assets found in world state
func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface) ([]*Asset, error) {
	// range query with empty string for startKey and endKey does an
	// open-ended query of all assets in the chaincode namespace.
	resultsIterator, err := ctx.GetStub().GetStateByRange("", "")
	if err != nil {
		return nil, err
	}
	defer resultsIterator.Close()
 
	var assets []*Asset
	for resultsIterator.HasNext() {
		queryResponse, err := resultsIterator.Next()
		if err != nil {
			return nil, err
		}
 
		var asset Asset
		err = json.Unmarshal(queryResponse.Value, &asset)
		if err != nil {
			return nil, err
		}
		assets = append(assets, &asset)
	}
 
	return assets, nil
}

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    查看虚拟机的IP和地址：

    ifconfig

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    gin框架

    package main
 
import (
	"bytes"
	"crypto/x509"
	"encoding/json"
	"fmt"
	"github.com/gin-gonic/gin"
	"github.com/hyperledger/fabric-gateway/pkg/client"
	"github.com/hyperledger/fabric-gateway/pkg/identity"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"io/ioutil"
	"path"
	"time"
)
 
const (
	mspID         = "Org1MSP"
	cryptoPath    = "./peerOrganizations/org1.example.com"
	certPath      = cryptoPath + "/users/User1@org1.example.com/msp/signcerts/cert.pem"
	keyPath       = cryptoPath + "/users/User1@org1.example.com/msp/keystore/"
	tlsCertPath   = cryptoPath + "/peers/peer0.org1.example.com/tls/ca.crt"
	peerEndpoint  = "192.168.136.130:7051"
	gatewayPeer   = "peer0.org1.example.com"
	channelName   = "mychannel"
	chaincodeName = "basic"
)
 
type Asset struct {
	AppraisedValue int    `form:"appraisedValue" json:"appraisedValue" `
	Color          string `form:"color" json:"color"`
	ID             string `form:"id" json:"id"`
	Owner          string `form:"owner" json:"owner"`
	Size           int    `form:"size" json:"size"`
}
 
func main() {
	// The gRPC client connection should be shared by all Gateway connections to this endpoint
	clientConnection := newGrpcConnection()
	defer clientConnection.Close()
 
	id := newIdentity()
	sign := newSign()
 
	// Create a Gateway connection for a specific client identity
	gateway, err := client.Connect(
		id,
		client.WithSign(sign),
		client.WithClientConnection(clientConnection),
		// Default timeouts for different gRPC calls
		client.WithEvaluateTimeout(5*time.Second),
		client.WithEndorseTimeout(15*time.Second),
		client.WithSubmitTimeout(5*time.Second),
		client.WithCommitStatusTimeout(1*time.Minute),
	)
	if err != nil {
		panic(err)
	}
	defer gateway.Close()
	network := gateway.GetNetwork(channelName)
	contract := network.GetContract(chaincodeName)
 
	r := gin.Default()
	r1 := r.Group("/fabric2.4")
	r1.POST("/CreateAsset", func(c *gin.Context) {
		var asset Asset
		c.ShouldBind(&asset)
		c.JSON(200, asset)
		marshal, _ := json.Marshal(asset)
		fmt.Println(string(marshal))
		fmt.Println("asset:", asset)
	})
	r1.POST("/GetAllAssets", func(c *gin.Context) {
		result := getAllAssets(contract)
		c.JSON(200, result)
	})
	r.Run(":8080") // 监听并在 0.0.0.0:8080 上启动服务
 
}
 
// Evaluate a transaction to query ledger state.
func getAllAssets(contract *client.Contract) string {
	fmt.Println("Evaluate Transaction: GetAllAssets, function returns all the current assets on the ledger")
 
	evaluateResult, err := contract.EvaluateTransaction("GetAllAssets")
	if err != nil {
		panic(fmt.Errorf("failed to evaluate transaction: %w", err))
	}
	result := formatJSON(evaluateResult)
 
	fmt.Printf("*** Result:%s\n", result)
 
	return string(evaluateResult)
}
 
// newGrpcConnection creates a gRPC connection to the Gateway server.
func newGrpcConnection() *grpc.ClientConn {
	certificate, err := loadCertificate(tlsCertPath)
	if err != nil {
		panic(err)
	}
 
	certPool := x509.NewCertPool()
	certPool.AddCert(certificate)
	transportCredentials := credentials.NewClientTLSFromCert(certPool, gatewayPeer)
 
	connection, err := grpc.Dial(peerEndpoint, grpc.WithTransportCredentials(transportCredentials))
	if err != nil {
		panic(fmt.Errorf("failed to create gRPC connection: %w", err))
	}
 
	return connection
}
 
// newIdentity creates a client identity for this Gateway connection using an X.509 certificate.
func newIdentity() *identity.X509Identity {
	certificate, err := loadCertificate(certPath)
	if err != nil {
		panic(err)
	}
 
	id, err := identity.NewX509Identity(mspID, certificate)
	if err != nil {
		panic(err)
	}
 
	return id
}
 
func loadCertificate(filename string) (*x509.Certificate, error) {
	certificatePEM, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil, fmt.Errorf("failed to read certificate file: %w", err)
	}
	return identity.CertificateFromPEM(certificatePEM)
}
 
// newSign creates a function that generates a digital signature from a message digest using a private key.
func newSign() identity.Sign {
	files, err := ioutil.ReadDir(keyPath)
	if err != nil {
		panic(fmt.Errorf("failed to read private key directory: %w", err))
	}
	privateKeyPEM, err := ioutil.ReadFile(path.Join(keyPath, files[0].Name()))
 
	if err != nil {
		panic(fmt.Errorf("failed to read private key file: %w", err))
	}
 
	privateKey, err := identity.PrivateKeyFromPEM(privateKeyPEM)
	if err != nil {
		panic(err)
	}
 
	sign, err := identity.NewPrivateKeySign(privateKey)
	if err != nil {
		panic(err)
	}
 
	return sign
}
 
// Format JSON data
func formatJSON(data []byte) string {
	var prettyJSON bytes.Buffer
	if err := json.Indent(&prettyJSON, data, " ", ""); err != nil {
		panic(fmt.Errorf("failed to parse JSON: %w", err))
	}
	return prettyJSON.String()
}

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    在这里插入图片描述

    链码

    package chaincode
 
import (
	"encoding/json"
	"fmt"
 
	"github.com/hyperledger/fabric-contract-api-go/contractapi"
)
 
// SmartContract provides functions for managing an Asset
type SmartContract struct {
	contractapi.Contract
}
 
// Asset describes basic details of what makes up a simple asset
//Insert struct field in alphabetic order => to achieve determinism across languages
// golang keeps the order when marshal to json but doesn't order automatically
type Asset struct {
	AppraisedValue int    `json:"AppraisedValue"`
	Color          string `json:"Color"`
	ID             string `json:"ID"`
	Owner          string `json:"Owner"`
	Size           int    `json:"Size"`
}
 
// InitLedger adds a base set of assets to the ledger
func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface) error {
	assets := []Asset{
		{ID: "asset1", Color: "blue", Size: 5, Owner: "Tomoko", AppraisedValue: 300},
		{ID: "asset2", Color: "red", Size: 5, Owner: "Brad", AppraisedValue: 400},
		{ID: "asset3", Color: "green", Size: 10, Owner: "Jin Soo", AppraisedValue: 500},
		{ID: "asset4", Color: "yellow", Size: 10, Owner: "Max", AppraisedValue: 600},
		{ID: "asset5", Color: "black", Size: 15, Owner: "Adriana", AppraisedValue: 700},
		{ID: "asset6", Color: "white", Size: 15, Owner: "Michel", AppraisedValue: 800},
	}
 
	for _, asset := range assets {
		assetJSON, err := json.Marshal(asset)
		if err != nil {
			return err
		}
 
		err = ctx.GetStub().PutState(asset.ID, assetJSON)
		if err != nil {
			return fmt.Errorf("failed to put to world state. %v", err)
		}
	}
 
	return nil
}
 
// CreateAsset issues a new asset to the world state with given details.
func (s *SmartContract) CreateAsset(ctx contractapi.TransactionContextInterface, id string, color string, size int, owner string, appraisedValue int) error {
	exists, err := s.AssetExists(ctx, id)
	if err != nil {
		return err
	}
	if exists {
		return fmt.Errorf("the asset %s already exists", id)
	}
 
	asset := Asset{
		ID:             id,
		Color:          color,
		Size:           size,
		Owner:          owner,
		AppraisedValue: appraisedValue,
	}
	assetJSON, err := json.Marshal(asset)
	if err != nil {
		return err
	}
 
	return ctx.GetStub().PutState(id, assetJSON)
}
 
// ReadAsset returns the asset stored in the world state with given id.
func (s *SmartContract) ReadAsset(ctx contractapi.TransactionContextInterface, id string) (*Asset, error) {
	assetJSON, err := ctx.GetStub().GetState(id)
	if err != nil {
		return nil, fmt.Errorf("failed to read from world state: %v", err)
	}
	if assetJSON == nil {
		return nil, fmt.Errorf("the asset %s does not exist", id)
	}
 
	var asset Asset
	err = json.Unmarshal(assetJSON, &asset)
	if err != nil {
		return nil, err
	}
 
	return &asset, nil
}
 
// UpdateAsset updates an existing asset in the world state with provided parameters.
func (s *SmartContract) UpdateAsset(ctx contractapi.TransactionContextInterface, id string, color string, size int, owner string, appraisedValue int) error {
	exists, err := s.AssetExists(ctx, id)
	if err != nil {
		return err
	}
	if !exists {
		return fmt.Errorf("the asset %s does not exist", id)
	}
 
	// overwriting original asset with new asset
	asset := Asset{
		ID:             id,
		Color:          color,
		Size:           size,
		Owner:          owner,
		AppraisedValue: appraisedValue,
	}
	assetJSON, err := json.Marshal(asset)
	if err != nil {
		return err
	}
 
	return ctx.GetStub().PutState(id, assetJSON)
}
 
// DeleteAsset deletes an given asset from the world state.
func (s *SmartContract) DeleteAsset(ctx contractapi.TransactionContextInterface, id string) error {
	exists, err := s.AssetExists(ctx, id)
	if err != nil {
		return err
	}
	if !exists {
		return fmt.Errorf("the asset %s does not exist", id)
	}
 
	return ctx.GetStub().DelState(id)
}
 
// AssetExists returns true when asset with given ID exists in world state
func (s *SmartContract) AssetExists(ctx contractapi.TransactionContextInterface, id string) (bool, error) {
	assetJSON, err := ctx.GetStub().GetState(id)
	if err != nil {
		return false, fmt.Errorf("failed to read from world state: %v", err)
	}
 
	return assetJSON != nil, nil
}
 
// TransferAsset updates the owner field of asset with given id in world state, and returns the old owner.
func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, id string, newOwner string) (string, error) {
	asset, err := s.ReadAsset(ctx, id)
	if err != nil {
		return "", err
	}
 
	oldOwner := asset.Owner
	asset.Owner = newOwner
 
	assetJSON, err := json.Marshal(asset)
	if err != nil {
		return "", err
	}
 
	err = ctx.GetStub().PutState(id, assetJSON)
	if err != nil {
		return "", err
	}
 
	return oldOwner, nil
}
 
// GetAllAssets returns all assets found in world state
func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface) ([]*Asset, error) {
	// range query with empty string for startKey and endKey does an
	// open-ended query of all assets in the chaincode namespace.
	resultsIterator, err := ctx.GetStub().GetStateByRange("", "")
	if err != nil {
		return nil, err
	}
	defer resultsIterator.Close()
 
	var assets []*Asset
	for resultsIterator.HasNext() {
		queryResponse, err := resultsIterator.Next()
		if err != nil {
			return nil, err
		}
 
		var asset Asset
		err = json.Unmarshal(queryResponse.Value, &asset)
		if err != nil {
			return nil, err
		}
		assets = append(assets, &asset)
	}
 
	return assets, nil
}

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    postman

    在这里插入图片描述
    测试自家网站：
    在这里插入图片描述
    在这里插入图片描述

    本地查询：
    在这里插入图片描述
    在这里插入图片描述
    自己的github：
    在这里插入图片描述

    请添加图片描述

    请添加图片描述
    请添加图片描述
    请添加图片描述

    实验二

    gin

    package main
 
import (
	"bytes"
	"crypto/x509"
	"encoding/json"
	"fmt"
	"github.com/gin-gonic/gin"
	"github.com/hyperledger/fabric-gateway/pkg/client"
	"github.com/hyperledger/fabric-gateway/pkg/identity"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"io/ioutil"
	"path"
	"time"
)
 
const (
	mspID         = "Org1MSP"
	cryptoPath    = "./peerOrganizations/org1.example.com"
	certPath      = cryptoPath + "/users/User1@org1.example.com/msp/signcerts/cert.pem"
	keyPath       = cryptoPath + "/users/User1@org1.example.com/msp/keystore/"
	tlsCertPath   = cryptoPath + "/peers/peer0.org1.example.com/tls/ca.crt"
	peerEndpoint  = "192.168.136.130:7051"
	gatewayPeer   = "peer0.org1.example.com"
	channelName   = "mychannel"
	chaincodeName = "basic"
)
 
type Asset struct {
	AppraisedValue int    `form:"appraisedValue" json:"appraisedValue" `
	Color          string `form:"color" json:"color"`
	ID             string `form:"id" json:"id"`
	Owner          string `form:"owner" json:"owner"`
	Size           int    `form:"size" json:"size"`
}
 
func main() {
	// The gRPC client connection should be shared by all Gateway connections to this endpoint
	clientConnection := newGrpcConnection()
	defer clientConnection.Close()
 
	id := newIdentity()
	sign := newSign()
 
	// Create a Gateway connection for a specific client identity
	gateway, err := client.Connect(
		id,
		client.WithSign(sign),
		client.WithClientConnection(clientConnection),
		// Default timeouts for different gRPC calls
		client.WithEvaluateTimeout(5*time.Second),
		client.WithEndorseTimeout(15*time.Second),
		client.WithSubmitTimeout(5*time.Second),
		client.WithCommitStatusTimeout(1*time.Minute),
	)
	if err != nil {
		panic(err)
	}
	defer gateway.Close()
	network := gateway.GetNetwork(channelName)
	contract := network.GetContract(chaincodeName)
 
	r := gin.Default()
	r1 := r.Group("/fabric2.4.2")
	r1.POST("/Init", func(c *gin.Context) {
		initLedger(contract)
		c.JSON(200, "init ok!")
	})
	r.Run(":8080") // 监听并在 0.0.0.0:8080 上启动服务
 
}
 
// Evaluate a transaction to query ledger state.
func getAllAssets(contract *client.Contract) string {
	fmt.Println("Evaluate Transaction: GetAllAssets, function returns all the current assets on the ledger")
 
	evaluateResult, err := contract.EvaluateTransaction("GetAllAssets")
	if err != nil {
		panic(fmt.Errorf("failed to evaluate transaction: %w", err))
	}
	result := formatJSON(evaluateResult)
 
	fmt.Printf("*** Result:%s\n", result)
 
	return string(evaluateResult)
}
 
// newGrpcConnection creates a gRPC connection to the Gateway server.
func newGrpcConnection() *grpc.ClientConn {
	certificate, err := loadCertificate(tlsCertPath)
	if err != nil {
		panic(err)
	}
 
	certPool := x509.NewCertPool()
	certPool.AddCert(certificate)
	transportCredentials := credentials.NewClientTLSFromCert(certPool, gatewayPeer)
 
	connection, err := grpc.Dial(peerEndpoint, grpc.WithTransportCredentials(transportCredentials))
	if err != nil {
		panic(fmt.Errorf("failed to create gRPC connection: %w", err))
	}
 
	return connection
}
 
// newIdentity creates a client identity for this Gateway connection using an X.509 certificate.
func newIdentity() *identity.X509Identity {
	certificate, err := loadCertificate(certPath)
	if err != nil {
		panic(err)
	}
 
	id, err := identity.NewX509Identity(mspID, certificate)
	if err != nil {
		panic(err)
	}
 
	return id
}
 
func loadCertificate(filename string) (*x509.Certificate, error) {
	certificatePEM, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil, fmt.Errorf("failed to read certificate file: %w", err)
	}
	return identity.CertificateFromPEM(certificatePEM)
}
 
// newSign creates a function that generates a digital signature from a message digest using a private key.
func newSign() identity.Sign {
	files, err := ioutil.ReadDir(keyPath)
	if err != nil {
		panic(fmt.Errorf("failed to read private key directory: %w", err))
	}
	privateKeyPEM, err := ioutil.ReadFile(path.Join(keyPath, files[0].Name()))
 
	if err != nil {
		panic(fmt.Errorf("failed to read private key file: %w", err))
	}
 
	privateKey, err := identity.PrivateKeyFromPEM(privateKeyPEM)
	if err != nil {
		panic(err)
	}
 
	sign, err := identity.NewPrivateKeySign(privateKey)
	if err != nil {
		panic(err)
	}
 
	return sign
}
 
// Format JSON data
func formatJSON(data []byte) string {
	var prettyJSON bytes.Buffer
	if err := json.Indent(&prettyJSON, data, " ", ""); err != nil {
		panic(fmt.Errorf("failed to parse JSON: %w", err))
	}
	return prettyJSON.String()
}

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    New asset部分：
    把下图代码：
    在这里插入图片描述
    改为这个：

    r1.POST("/CreateAsset", func(c *gin.Context) {
		var asset Asset
		c.ShouldBind(&asset)
		c.JSON(200, asset)
		marshal, _ := json.Marshal(asset)
		CreateAsset(contract, asset)
		fmt.Println("存入成功！存入的数据是:", string(marshal))
		//fmt.Println("asset:", asset)
	})

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    函数：

    func CreateAsset(contract *client.Contract, asset Asset) string {
	evaluateResult, err := contract.SubmitTransaction("CreateAsset", asset.ID, asset.Color, strconv.Itoa(asset.Size), asset.Owner, strconv.Itoa(asset.AppraisedValue))
	if err != nil {
		panic(fmt.Errorf("failed to evaluate transaction: %w", err))
	}
	result := formatJSON(evaluateResult)
 
	fmt.Printf("*** Result:%s\n", result)
 
	return string(evaluateResult)
}

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    在这里插入图片描述
    在这里插入图片描述

    总结

    本次实验内容内容不多，难度颇大。
    其一在于作者默认搭好框架，所以需要按照前文做出适配。
    其二是网络搭好之后的查询，如果看了前文，可以知道作者是修改了

    https://github.com/hyperledger/fabric-samples/tree/main/asset-transfer-basic

    部分的代码，也就是本文的gin框架部分。修改也很多，
    在这里插入图片描述
    然后就是代码，代码在我这里经常报错，然后为了解决一个bug往往会搞出更多的问题，尤其是网络接口的占用，就在写文档的现在，我的7051端口莫名被占用了，为了更好完成期末任务，决定找一个正确而清晰的文档从头开始配置。（很大的原因是这几次作业下来整个fabric文件夹臃肿不堪，fabric-samples就有好几个，隔着几周时间回去看，有能运行的，也有当初是坑，后来没删的，总之，归零重启更有效）

    在做两个实验之前，我先按照作者的思路配置了环境，主要是启动网络。
    其次是一种很新的工具，postman，现在还没有完全摸清这个软件的用途，目前仅做查询网址用途。

    第二个查询部分没有把assets查出来，可能是某个方面出了bug，之后会重新启用虚拟机，然后从头开始做一遍。

    请添加图片描述

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  • 原文地址：https://blog.csdn.net/Algernon98/article/details/128009665