A testing chaincode to show what happens if more than a transaction acting on a state in a block cycle

testblocktime.go

package main

import (
	"fmt"
	"strconv"

	"github.com/hyperledger/fabric/core/chaincode/shim"
	pb "github.com/hyperledger/fabric/protos/peer"
)

type TestBlockTime struct {
}

func (t *TestBlockTime) Init(stub shim.ChaincodeStubInterface) pb.Response {
	var initValue int
	initValue = 0
	err := stub.PutState("value", []byte(strconv.Itoa(initValue)))
	if err != nil {
		return shim.Error(err.Error())
	}
	return shim.Success(nil)
}

func (t *TestBlockTime) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
	function, args := stub.GetFunctionAndParameters()
	if function == "add" {
		return t.add(stub, args)
	} else if function == "get" {
		return t.get(stub)
	} else if function == "set" {
		return t.set(stub, args)
	}
	return shim.Error("Invalid function")
}

func (t *TestBlockTime) add(stub shim.ChaincodeStubInterface, args []string) pb.Response {
	var value, state int
	var err error
	if len(args) != 1 {
		return shim.Error("Only one argument needed.")
	}
	value, err = strconv.Atoi(args[0])
	if err != nil {
		return shim.Error("Expecting integer")
	}
	stateAsBytes, err := stub.GetState("value")
	if err != nil {
		return shim.Error("Failed to get state")
	}
	state, _ = strconv.Atoi(string(stateAsBytes))

	state = state + value

	err = stub.PutState("value", []byte(strconv.Itoa(state)))
	if err != nil {
		return shim.Error(err.Error())
	}
	return shim.Success(nil)
}

func (t *TestBlockTime) get(stub shim.ChaincodeStubInterface) pb.Response {
	stateAsBytes, err := stub.GetState("value")
	if err != nil {
		return shim.Error("Failed to get state")
	}
	return shim.Success(stateAsBytes)
}

func (t *TestBlockTime) set(stub shim.ChaincodeStubInterface, args []string) pb.Response {
	var value int
	var err error
	if len(args) != 1 {
		return shim.Error("Only one argument needed.")
	}
	value, err = strconv.Atoi(args[0])
	if err != nil {
		return shim.Error("Expecting integer")
	}

	err = stub.PutState("value", []byte(strconv.Itoa(value)))
	if err != nil {
		return shim.Error(err.Error())
	}
	return shim.Success(nil)
}

func main() {
	err := shim.Start(new(TestBlockTime))
	if err != nil {
		fmt.Printf("Error starting chaincode: %s", err)
	}
}