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| package main
import (
"encoding/json"
"fmt"
"log"
"github.com/hyperledger/fabric-contract-api-go/contractapi"
)
type SmartContract struct {
contractapi.Contract
}
type Asset struct {
ID string `json:"ID"`
Owner string `json:"owner"`
Value int `json:"Value"`
}
func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface) error {
assets := []Asset{
{ID: "asset1", Owner: "ZhangSan", Value: 300},
{ID: "asset2", Owner: "LiSi", Value: 400},
{ID: "asset3", Owner: "Klay", Value: 500},
}
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
}
func (s *SmartContract) CreateAsset(ctx contractapi.TransactionContextInterface, id string, owner string, Value 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,
Owner: owner,
Value: Value,
}
assetJSON, err := json.Marshal(asset)
if err != nil {
return err
}
return ctx.GetStub().PutState(id, assetJSON)
}
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
}
func (s *SmartContract) UpdateAsset(ctx contractapi.TransactionContextInterface, id string, owner string, Value 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)
}
asset := Asset{
ID: id,
Owner: owner,
Value: Value,
}
assetJSON, err := json.Marshal(asset)
if err != nil {
return err
}
return ctx.GetStub().PutState(id, assetJSON)
}
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)
}
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
}
func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, id string, newOwner string) error {
asset, err := s.ReadAsset(ctx, id)
if err != nil {
return err
}
asset.Owner = newOwner
assetJSON, err := json.Marshal(asset)
if err != nil {
return err
}
return ctx.GetStub().PutState(id, assetJSON)
}
func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface) ([]*Asset, error) {
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
}
func main() {
assetChaincode, err := contractapi.NewChaincode(&SmartContract{})
if err != nil {
log.Panicf("Error creating asset-transfer-basic chaincode: %v", err)
}
if err := assetChaincode.Start(); err != nil {
log.Panicf("Error starting asset-transfer-basic chaincode: %v", err)
}
}
|
