// Query callback representing the query of a chaincode
func (t *AssetManagementChaincode) Query(stub *shim.ChaincodeStub, function string, args []string) ([]byte, error) {
	if function != "query" {
		return nil, errors.New("Invalid query function name. Expecting \"query\"")
	}

	var err error

	if len(args) != 1 {
		return nil, errors.New("Incorrect number of arguments. Expecting name of an asset to query")
	}

	// Who is the owner of the asset?
	asset := args[0]

	var columns []shim.Column
	col1 := shim.Column{Value: &shim.Column_String_{String_: asset}}
	columns = append(columns, col1)

	row, err := stub.GetRow("AssetsOwnership", columns)
	if err != nil {
		jsonResp := "{\"Error\":\"Failed retrieveing asset " + asset + ". Error " + err.Error() + ". \"}"
		return nil, errors.New(jsonResp)
	}

	jsonResp := "{\"Owner\":\"" + string(row.Columns[1].GetBytes()) + "\"}"
	fmt.Printf("Query Response:%s\n", jsonResp)

	return row.Columns[1].GetBytes(), nil
}
func (t *AssetManagementChaincode) transfer(stub *shim.ChaincodeStub, args []string) ([]byte, error) {
	if len(args) != 2 {
		return nil, errors.New("Incorrect number of arguments. Expecting 2")
	}

	asset := args[0]
	newOwner := []byte(args[1])

	// Verify the identity of the caller
	// Only the owner can transfer one of his assets
	var columns []shim.Column
	col1 := shim.Column{Value: &shim.Column_String_{String_: asset}}
	columns = append(columns, col1)

	row, err := stub.GetRow("AssetsOwnership", columns)
	if err != nil {
		return nil, fmt.Errorf("Failed retrieveing asset [%s]: [%s]", asset, err)
	}

	prvOwner := row.Columns[1].GetBytes()
	myLogger.Debug("Previous owener of [%s] is [% x]", asset, prvOwner)
	if len(prvOwner) == 0 {
		return nil, fmt.Errorf("Invalid previous owner. Nil")
	}

	// Verify ownership
	ok, err := t.isCaller(stub, prvOwner)
	if err != nil {
		return nil, errors.New("Failed checking asset owner identity")
	}
	if !ok {
		return nil, errors.New("The caller is not the owner of the asset")
	}

	// At this point, the proof of ownership is valid, then register transfer
	err = stub.DeleteRow(
		"AssetsOwnership",
		[]shim.Column{shim.Column{Value: &shim.Column_String_{String_: asset}}},
	)
	if err != nil {
		return nil, errors.New("Failed deliting row.")
	}

	_, err = stub.InsertRow(
		"AssetsOwnership",
		shim.Row{
			Columns: []*shim.Column{
				&shim.Column{Value: &shim.Column_String_{String_: asset}},
				&shim.Column{Value: &shim.Column_Bytes{Bytes: newOwner}},
			},
		})
	if err != nil {
		return nil, errors.New("Failed inserting row.")
	}

	return nil, nil
}
Exemple #3
0
// Query callback representing the query of a chaincode
func (t *SimpleChaincode) Query(stub *shim.ChaincodeStub, function string, args []string) ([]byte, error) {
	switch function {

	case "getRowTableOne":
		if len(args) < 1 {
			return nil, errors.New("getRowTableOne failed. Must include 1 key value")
		}

		col1Val := args[0]
		var columns []shim.Column
		col1 := shim.Column{Value: &shim.Column_String_{String_: col1Val}}
		columns = append(columns, col1)

		row, err := stub.GetRow("tableOne", columns)
		if err != nil {
			return nil, fmt.Errorf("getRowTableOne operation failed. %s", err)
		}

		rowString := fmt.Sprintf("%s", row)
		return []byte(rowString), nil

	case "getRowTableTwo":
		if len(args) < 3 {
			return nil, errors.New("getRowTableTwo failed. Must include 3 key values")
		}

		col1Val := args[0]
		col2Int, err := strconv.ParseInt(args[1], 10, 32)
		if err != nil {
			return nil, errors.New("getRowTableTwo failed. arg[1] must be convertable to int32")
		}
		col2Val := int32(col2Int)
		col3Val := args[2]
		var columns []shim.Column
		col1 := shim.Column{Value: &shim.Column_String_{String_: col1Val}}
		col2 := shim.Column{Value: &shim.Column_Int32{Int32: col2Val}}
		col3 := shim.Column{Value: &shim.Column_String_{String_: col3Val}}
		columns = append(columns, col1)
		columns = append(columns, col2)
		columns = append(columns, col3)

		row, err := stub.GetRow("tableTwo", columns)
		if err != nil {
			return nil, fmt.Errorf("getRowTableTwo operation failed. %s", err)
		}

		rowString := fmt.Sprintf("%s", row)
		return []byte(rowString), nil

	case "getRowTableThree":
		if len(args) < 1 {
			return nil, errors.New("getRowTableThree failed. Must include 1 key value")
		}

		col1Val := args[0]

		var columns []shim.Column
		col1 := shim.Column{Value: &shim.Column_String_{String_: col1Val}}
		columns = append(columns, col1)

		row, err := stub.GetRow("tableThree", columns)
		if err != nil {
			return nil, fmt.Errorf("getRowTableThree operation failed. %s", err)
		}

		rowString := fmt.Sprintf("%s", row)
		return []byte(rowString), nil

	case "getRowsTableTwo":
		if len(args) < 1 {
			return nil, errors.New("getRowsTableTwo failed. Must include at least key values")
		}

		var columns []shim.Column

		col1Val := args[0]
		col1 := shim.Column{Value: &shim.Column_String_{String_: col1Val}}
		columns = append(columns, col1)

		if len(args) > 1 {
			col2Int, err := strconv.ParseInt(args[1], 10, 32)
			if err != nil {
				return nil, errors.New("getRowsTableTwo failed. arg[1] must be convertable to int32")
			}
			col2Val := int32(col2Int)
			col2 := shim.Column{Value: &shim.Column_Int32{Int32: col2Val}}
			columns = append(columns, col2)
		}

		rowChannel, err := stub.GetRows("tableTwo", columns)
		if err != nil {
			return nil, fmt.Errorf("getRowsTableTwo operation failed. %s", err)
		}

		var rows []shim.Row
		for {
			select {
			case row, ok := <-rowChannel:
				if !ok {
					rowChannel = nil
				} else {
					rows = append(rows, row)
				}
			}
			if rowChannel == nil {
				break
			}
		}

		jsonRows, err := json.Marshal(rows)
		if err != nil {
			return nil, fmt.Errorf("getRowsTableTwo operation failed. Error marshaling JSON: %s", err)
		}

		return jsonRows, nil

	default:
		return nil, errors.New("Unsupported operation")
	}
}