invoke-first-iter.go

func (cci *PreciousCargoChaincode) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
	function, args := stub.GetFunctionAndParameters()
	if function == "registerParticipant" {
		if len(args) != 1 {
			return shim.Error("expecting JSON input as first param")
		}

		// (1) parse input
		arg := struct {
			Name    string `json:"name"`
			Address string `json:"address"`
		}{}
		err := json.Unmarshal([]byte(args[0]), &arg)
		if err != nil {
			return shim.Error("invalid JSON")
		}

		// (2) Create an ID for the new participant
		idStr, err := newID(stub, "IndividualParticipant")
		if err != nil {
			return shim.Error("internal error generating index key")
		}

		// (3) create data item for world state update
		p := IndividualParticipant{
			Participant: Participant{
				ID: ID{
					ID: idStr,
				},
				Name: arg.Name,
			},
			Address: arg.Address,
		}

		ck, err := stub.CreateCompositeKey("co.preciousgoodsshipping.IndividualParticipant#", []string{idStr})
		if err != nil {
			return shim.Error("error creating key")
		}

		// (4) marshal data to json and ...
		data, err := json.Marshal(p)
		if err != nil {
			return shim.Error("internal JSON marshal error (1)")
		}
		// (5) ... save to world state
		err = stub.PutState(ck, []byte(data))
		if err != nil {
			return shim.Error("internal error writing world state")
		}

		// return ID of new participant
		return shim.Success([]byte(idStr))
	}

	return shim.Error("Invalid transaction name.")
}