fabric-samples/test-network/snippet.go

// CreateAsset creates a new asset by placing the main asset details in the assetCollection
// that can be read by both organizations. The appraisal value is stored in the owners org specific collection.
func (s *SmartContract) CreateAsset(ctx contractapi.TransactionContextInterface) error {

	// Get new asset from transient map
	transientMap, err := ctx.GetStub().GetTransient()
	if err != nil {
		return fmt.Errorf("error getting transient: %v", err)
	}

	// Asset properties are private, therefore they get passed in transient field, instead of func args
	transientAssetJSON, ok := transientMap["asset_properties"]
	if !ok {
		//log error to stdout
		return fmt.Errorf("asset not found in the transient map input")
	}

	type assetTransientInput struct {
		Type           string `json:"objectType"` //Type is used to distinguish the various types of objects in state database
		ID             string `json:"assetID"`
		Color          string `json:"color"`
		Size           int    `json:"size"`
		AppraisedValue int    `json:"appraisedValue"`
	}

	var assetInput assetTransientInput
	err = json.Unmarshal(transientAssetJSON, &assetInput)
	if err != nil {
		return fmt.Errorf("failed to unmarshal JSON: %v", err)
	}

	if len(assetInput.Type) == 0 {
		return fmt.Errorf("objectType field must be a non-empty string")
	}
	if len(assetInput.ID) == 0 {
		return fmt.Errorf("assetID field must be a non-empty string")
	}
	if len(assetInput.Color) == 0 {
		return fmt.Errorf("color field must be a non-empty string")
	}
	if assetInput.Size <= 0 {
		return fmt.Errorf("size field must be a positive integer")
	}
	if assetInput.AppraisedValue <= 0 {
		return fmt.Errorf("appraisedValue field must be a positive integer")
	}

	// Check if asset already exists
	assetAsBytes, err := ctx.GetStub().GetPrivateData(assetCollection, assetInput.ID)
	if err != nil {
		return fmt.Errorf("failed to get asset: %v", err)
	} else if assetAsBytes != nil {
		fmt.Println("Asset already exists: " + assetInput.ID)
		return fmt.Errorf("this asset already exists: " + assetInput.ID)
	}

	// Get ID of submitting client identity
	clientID, err := submittingClientIdentity(ctx)
	if err != nil {
		return err
	}

	// Verify that the client is submitting request to peer in their organization
	// This is to ensure that a client from another org doesn't attempt to read or
	// write private data from this peer.
	err = verifyClientOrgMatchesPeerOrg(ctx)
	if err != nil {
		return fmt.Errorf("CreateAsset cannot be performed: Error %v", err)
	}

	// Make submitting client the owner
	asset := Asset{
		Type:  assetInput.Type,
		ID:    assetInput.ID,
		Color: assetInput.Color,
		Size:  assetInput.Size,
		Owner: clientID,
	}
	assetJSONasBytes, err := json.Marshal(asset)
	if err != nil {
		return fmt.Errorf("failed to marshal asset into JSON: %v", err)
	}

	// Save asset to private data collection
	// Typical logger, logs to stdout/file in the fabric managed docker container, running this chaincode
	// Look for container name like dev-peer0.org1.example.com-{chaincodename_version}-xyz
	log.Printf("CreateAsset Put: collection %v, ID %v, owner %v", assetCollection, assetInput.ID, clientID)

	err = ctx.GetStub().PutPrivateData(assetCollection, assetInput.ID, assetJSONasBytes)
	if err != nil {
		return fmt.Errorf("failed to put asset into private data collection: %v", err)
	}

	// Save asset details to collection visible to owning organization
	assetPrivateDetails := AssetPrivateDetails{
		ID:             assetInput.ID,
		AppraisedValue: assetInput.AppraisedValue,
	}

	assetPrivateDetailsAsBytes, err := json.Marshal(assetPrivateDetails) // marshal asset details to JSON
	if err != nil {
		return fmt.Errorf("failed to marshal into JSON: %v", err)
	}

	// Get collection name for this organization.
	orgCollection, err := getCollectionName(ctx)
	if err != nil {
		return fmt.Errorf("failed to infer private collection name for the org: %v", err)
	}

	// Put asset appraised value into owners org specific private data collection
	log.Printf("Put: collection %v, ID %v", orgCollection, assetInput.ID)
	err = ctx.GetStub().PutPrivateData(orgCollection, assetInput.ID, assetPrivateDetailsAsBytes)
	if err != nil {
		return fmt.Errorf("failed to put asset private details: %v", err)
	}
	return nil
}