cars.go

// Simple CRUD chaincode for store information about cars
package cars

import (
	"time"

	"github.com/hyperledger-labs/cckit/extensions/owner"
	"github.com/hyperledger-labs/cckit/router"
	p "github.com/hyperledger-labs/cckit/router/param"
)

const CarEntity = `CAR`
const CarRegisteredEvent = `CAR_REGISTERED`

// CarPayload chaincode method argument
type CarPayload struct {
	Id    string
	Title string
	Owner string
}

// Car struct for chaincode state
type Car struct {
	Id    string
	Title string
	Owner string

	UpdatedAt time.Time // set by chaincode method
}

// Key for car entry in chaincode state
func (c Car) Key() ([]string, error) {
	return []string{CarEntity, c.Id}, nil
}

func New() *router.Chaincode {
	r := router.New(`cars`) // also initialized logger with "cars" prefix

	r.Init(invokeInit)

	r.Group(`car`).
		Query(`List`, queryCars).                                             // chain code method name is carList
		Query(`Get`, queryCar, p.String(`id`)).                               // chain code method name is carGet, method has 1 string argument "id"
		Invoke(`Register`, invokeCarRegister, p.Struct(`car`, &CarPayload{}), // 1 struct argument
			owner.Only) // allow access to method only for chaincode owner (authority)

	return router.NewChaincode(r)
}

// ======= Init ==================
func invokeInit(c router.Context) (interface{}, error) {
	return owner.SetFromCreator(c)
}

// ======= Chaincode methods =====

// car get info chaincode method handler
func queryCar(c router.Context) (interface{}, error) {
	// get state entry by composite key using CarKeyPrefix and car.Id
	//  and unmarshal from []byte to Car struct
	return c.State().Get(&Car{Id: c.ParamString(`id`)})
}

// cars car list chaincode method handler
func queryCars(c router.Context) (interface{}, error) {
	return c.State().List(
		CarEntity, // get list of state entries of type CarKeyPrefix
		&Car{})    // unmarshal from []byte and append to []Car slice
}

// carRegister car register chaincode method handler
func invokeCarRegister(c router.Context) (interface{}, error) {
	// arg name defined in router method definition
	p := c.Param(`car`).(CarPayload)

	t, _ := c.Time() // tx time
	car := &Car{     // data for chaincode state
		Id:        p.Id,
		Title:     p.Title,
		Owner:     p.Owner,
		UpdatedAt: t,
	}

	// trigger multiple event
	if err := c.Event().Set(CarRegisteredEvent+`First`, car); err != nil {
		return nil, err
	}

	if err := c.Event().Set(CarRegisteredEvent, car); err != nil {
		return nil, err
	}

	return car, // peer.Response payload will be json serialized car data
		//put json serialized data to state
		// create composite key using CarKeyPrefix and car.Id
		c.State().Insert(car)
}