Cars chaincode methods implementation

cars_chaincode_methods_implementation.go

// Key for car entry in chaincode state
func Key(id string) []string {
	return []string{CarKeyPrefix, id}
}

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

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

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

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

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