Add Go implementation of full-stack asset transfer smart contract

full-stack-asset-transfer-guide/contracts/asset-transfer-go/go.mod

@@ -0,0 +1,28 @@
+module github.com/hyperledger/fabric-samples/full-stack-asset-transfer-guide/contracts/asset-transfer-go
+
+go 1.23
+
+require (
+	github.com/hyperledger/fabric-chaincode-go/v2 v2.0.0
+	github.com/hyperledger/fabric-contract-api-go/v2 v2.2.0
+)
+
+require (
+	github.com/go-openapi/jsonpointer v0.21.0 // indirect
+	github.com/go-openapi/jsonreference v0.21.0 // indirect
+	github.com/go-openapi/spec v0.21.0 // indirect
+	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/hyperledger/fabric-protos-go-apiv2 v0.3.4 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
+	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
+	github.com/xeipuuv/gojsonschema v1.2.0 // indirect
+	golang.org/x/net v0.28.0 // indirect
+	golang.org/x/sys v0.24.0 // indirect
+	golang.org/x/text v0.17.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240814211410-ddb44dafa142 // indirect
+	google.golang.org/grpc v1.67.0 // indirect
+	google.golang.org/protobuf v1.36.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

full-stack-asset-transfer-guide/contracts/asset-transfer-go/go.sum

@@ -0,0 +1,61 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
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+github.com/go-openapi/jsonpointer v0.21.0 h1:YgdVicSA9vH5RiHs9TZW5oyafXZFc6+2Vc1rr/O9oNQ=
+github.com/go-openapi/jsonpointer v0.21.0/go.mod h1:IUyH9l/+uyhIYQ/PXVA41Rexl+kOkAPDdXEYns6fzUY=
+github.com/go-openapi/jsonreference v0.21.0 h1:Rs+Y7hSXT83Jacb7kFyjn4ijOuVGSvOdF2+tg1TRrwQ=
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+github.com/go-openapi/spec v0.21.0 h1:LTVzPc3p/RzRnkQqLRndbAzjY0d0BCL72A6j3CdL9ZY=
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+github.com/go-openapi/swag v0.23.0 h1:vsEVJDUo2hPJ2tu0/Xc+4noaxyEffXNIs3cOULZ+GrE=
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+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/hyperledger/fabric-chaincode-go/v2 v2.0.0 h1:IhkHfrl5X/fVnmB6pWeCYCdIJRi9bxj+WTnVN8DtW3c=
+github.com/hyperledger/fabric-chaincode-go/v2 v2.0.0/go.mod h1:PHHaFffjw7p7n9bmCfcm7RqDqYdivNEsJdiNIKZo5Lk=
+github.com/hyperledger/fabric-contract-api-go/v2 v2.2.0 h1:rmUoBmciB0GL/miqcbJmJbgp5QTWoJUrZo+CNxrNLF4=
+github.com/hyperledger/fabric-contract-api-go/v2 v2.2.0/go.mod h1:FeWeO/jwGjiME7ak3GufqKIcwkejtzrDG4QxbfKydWs=
+github.com/hyperledger/fabric-protos-go-apiv2 v0.3.4 h1:YJrd+gMaeY0/vsN0aS0QkEKTivGoUnSRIXxGJ7KI+Pc=
+github.com/hyperledger/fabric-protos-go-apiv2 v0.3.4/go.mod h1:bau/6AJhvEcu9GKKYHlDXAxXKzYNfhP6xu2GXuxEcFk=
+github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
+github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
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+github.com/rogpeppe/go-internal v1.12.0 h1:exVL4IDcn6na9z1rAb56Vxr+CgyK3nn3O+epU5NdKM8=
+github.com/rogpeppe/go-internal v1.12.0/go.mod h1:E+RYuTGaKKdloAfM02xzb0FW3Paa99yedzYV+kq4uf4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
+github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
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+github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
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+github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415/go.mod h1:GwrjFmJcFw6At/Gs6z4yjiIwzuJ1/+UwLxMQDVQXShQ=
+github.com/xeipuuv/gojsonschema v1.2.0 h1:LhYJRs+L4fBtjZUfuSZIKGeVu0QRy8e5Xi7D17UxZ74=
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+golang.org/x/net v0.28.0 h1:a9JDOJc5GMUJ0+UDqmLT86WiEy7iWyIhz8gz8E4e5hE=
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+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

full-stack-asset-transfer-guide/contracts/asset-transfer-go/main.go

@@ -0,0 +1,23 @@
+/*
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package main
+
+import (
+	"log"
+
+	"github.com/hyperledger/fabric-contract-api-go/v2/contractapi"
+	asset "github.com/hyperledger/fabric-samples/full-stack-asset-transfer-guide/contracts/asset-transfer-go/smartcontract"
+)
+
+func main() {
+	assetChaincode, err := contractapi.NewChaincode(&asset.SmartContract{})
+	if err != nil {
+		log.Panicf("Error creating asset-transfer-go chaincode: %v", err)
+	}
+
+	if err := assetChaincode.Start(); err != nil {
+		log.Panicf("Error starting asset-transfer-go chaincode: %v", err)
+	}
+}

full-stack-asset-transfer-guide/contracts/asset-transfer-go/smartcontract/asset.go

@@ -0,0 +1,14 @@
+/*
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package smartcontract
+
+// Asset represents a tradeable asset in the world state.
+type Asset struct {
+	ID             string `json:"ID"`
+	Color          string `json:"Color"`
+	Owner          string `json:"Owner"`
+	AppraisedValue int    `json:"AppraisedValue"`
+	Size           int    `json:"Size"`
+}

full-stack-asset-transfer-guide/contracts/asset-transfer-go/smartcontract/asset_transfer.go

@@ -0,0 +1,258 @@
+/*
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package smartcontract
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+
+	"github.com/hyperledger/fabric-contract-api-go/v2/contractapi"
+)
+
+type SmartContract struct {
+	contractapi.Contract
+}
+
+func (s *SmartContract) CreateAsset(ctx contractapi.TransactionContextInterface, asset *Asset) error {
+	if asset == nil {
+		return fmt.Errorf("asset cannot be nil")
+	}
+
+	if asset.ID == "" {
+		return fmt.Errorf("Missing ID")
+	}
+
+	ownerIdentifier, err := clientIdentifierWithUser(ctx, asset.Owner)
+	if err != nil {
+		return err
+	}
+
+	asset.Owner, err = marshalOwnerIdentifier(ownerIdentifier)
+	if err != nil {
+		return err
+	}
+
+	exists, err := s.AssetExists(ctx, asset.ID)
+	if err != nil {
+		return err
+	}
+	if exists {
+		return fmt.Errorf("The asset %s already exists", asset.ID)
+	}
+
+	assetBytes, err := json.Marshal(asset)
+	if err != nil {
+		return fmt.Errorf("failed to marshal asset: %v", err)
+	}
+
+	if err := ctx.GetStub().PutState(asset.ID, assetBytes); err != nil {
+		return fmt.Errorf("failed to put asset in world state: %v", err)
+	}
+
+	clientMSP, err := ctx.GetClientIdentity().GetMSPID()
+	if err != nil {
+		return fmt.Errorf("failed to get client MSP ID: %v", err)
+	}
+
+	if err := setStateBasedEndorsement(ctx, asset.ID, clientMSP); err != nil {
+		return err
+	}
+
+	if err := ctx.GetStub().SetEvent("CreateAsset", assetBytes); err != nil {
+		return fmt.Errorf("failed to set event CreateAsset: %v", err)
+	}
+
+	return nil
+}
+
+func (s *SmartContract) ReadAsset(ctx contractapi.TransactionContextInterface, id string) (*Asset, error) {
+	assetBytes, err := s.readAsset(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+
+	var asset Asset
+	if err := json.Unmarshal(assetBytes, &asset); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal asset: %v", err)
+	}
+
+	return &asset, nil
+}
+
+func (s *SmartContract) UpdateAsset(ctx contractapi.TransactionContextInterface, assetUpdate *Asset) error {
+	if assetUpdate == nil {
+		return fmt.Errorf("asset cannot be nil")
+	}
+	if assetUpdate.ID == "" {
+		return fmt.Errorf("No asset ID specified")
+	}
+
+	existingAsset, err := s.ReadAsset(ctx, assetUpdate.ID)
+	if err != nil {
+		return err
+	}
+
+	allowed, err := hasWritePermission(ctx, existingAsset)
+	if err != nil {
+		return err
+	}
+	if !allowed {
+		return fmt.Errorf("Only owner can update assets")
+	}
+
+	updatedAsset := *existingAsset
+	if assetUpdate.Color != "" {
+		updatedAsset.Color = assetUpdate.Color
+	}
+	if assetUpdate.Size != 0 {
+		updatedAsset.Size = assetUpdate.Size
+	}
+	if assetUpdate.AppraisedValue != 0 {
+		updatedAsset.AppraisedValue = assetUpdate.AppraisedValue
+	}
+
+	assetBytes, err := json.Marshal(&updatedAsset)
+	if err != nil {
+		return fmt.Errorf("failed to marshal updated asset: %v", err)
+	}
+
+	if err := ctx.GetStub().PutState(updatedAsset.ID, assetBytes); err != nil {
+		return fmt.Errorf("failed to put asset in world state: %v", err)
+	}
+
+	clientMSP, err := ctx.GetClientIdentity().GetMSPID()
+	if err != nil {
+		return fmt.Errorf("failed to get client MSP ID: %v", err)
+	}
+
+	if err := setStateBasedEndorsement(ctx, updatedAsset.ID, clientMSP); err != nil {
+		return err
+	}
+
+	if err := ctx.GetStub().SetEvent("UpdateAsset", assetBytes); err != nil {
+		return fmt.Errorf("failed to set event UpdateAsset: %v", err)
+	}
+
+	return nil
+}
+
+func (s *SmartContract) DeleteAsset(ctx contractapi.TransactionContextInterface, id string) error {
+	asset, err := s.ReadAsset(ctx, id)
+	if err != nil {
+		return err
+	}
+
+	allowed, err := hasWritePermission(ctx, asset)
+	if err != nil {
+		return err
+	}
+	if !allowed {
+		return fmt.Errorf("Only owner can delete assets")
+	}
+
+	if err := ctx.GetStub().DelState(id); err != nil {
+		return fmt.Errorf("failed to delete asset from world state: %v", err)
+	}
+
+	assetBytes, err := json.Marshal(asset)
+	if err != nil {
+		return fmt.Errorf("failed to marshal asset event payload: %v", err)
+	}
+
+	if err := ctx.GetStub().SetEvent("DeleteAsset", assetBytes); err != nil {
+		return fmt.Errorf("failed to set event DeleteAsset: %v", err)
+	}
+
+	return nil
+}
+
+func (s *SmartContract) AssetExists(ctx contractapi.TransactionContextInterface, id string) (bool, error) {
+	assetBytes, err := ctx.GetStub().GetState(id)
+	if err != nil {
+		return false, fmt.Errorf("failed to read from world state: %v", err)
+	}
+
+	return len(assetBytes) > 0, nil
+}
+
+func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, id string, newOwner string, newOwnerOrg string) error {
+	asset, err := s.ReadAsset(ctx, id)
+	if err != nil {
+		return err
+	}
+
+	allowed, err := hasWritePermission(ctx, asset)
+	if err != nil {
+		return err
+	}
+	if !allowed {
+		return fmt.Errorf("Only owner can transfer assets")
+	}
+
+	asset.Owner, err = marshalOwnerIdentifier(ownerIdentifier(newOwner, newOwnerOrg))
+	if err != nil {
+		return err
+	}
+
+	assetBytes, err := json.Marshal(asset)
+	if err != nil {
+		return fmt.Errorf("failed to marshal transferred asset: %v", err)
+	}
+
+	if err := ctx.GetStub().PutState(id, assetBytes); err != nil {
+		return fmt.Errorf("failed to put asset in world state: %v", err)
+	}
+
+	if err := setStateBasedEndorsement(ctx, id, newOwnerOrg); err != nil {
+		return err
+	}
+
+	if err := ctx.GetStub().SetEvent("TransferAsset", assetBytes); err != nil {
+		return fmt.Errorf("failed to set event TransferAsset: %v", err)
+	}
+
+	return nil
+}
+
+func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface) ([]*Asset, error) {
+	iterator, err := ctx.GetStub().GetStateByRange("", "")
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve all assets: %v", err)
+	}
+	defer func() {
+		_ = iterator.Close()
+	}()
+
+	assets := make([]*Asset, 0)
+	for iterator.HasNext() {
+		queryResponse, err := iterator.Next()
+		if err != nil {
+			return nil, fmt.Errorf("failed retrieving next item: %v", err)
+		}
+
+		var asset Asset
+		if err := json.Unmarshal(queryResponse.Value, &asset); err != nil {
+			log.Printf("failed to unmarshal asset from world state: %v", err)
+			continue
+		}
+		assets = append(assets, &asset)
+	}
+
+	return assets, nil
+}
+
+func (s *SmartContract) readAsset(ctx contractapi.TransactionContextInterface, id string) ([]byte, error) {
+	assetBytes, err := ctx.GetStub().GetState(id)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read from world state: %v", err)
+	}
+
+	if len(assetBytes) == 0 {
+		return nil, fmt.Errorf("Sorry, asset %s has not been created", id)
+	}
+
+	return assetBytes, nil
+}