Chaincode code example for Hyperledger Fabric

mychaincode.go

package main

import (
   "github.com/hyperledger/fabric/core/chaincode/shim"
   sc "github.com/hyperledger/fabric/protos/peer"
)

type SmartContract struct {
    // Here we can store specific smartcontract data
}

type Asset struct {
    Name string `json:"name"`
}

/*
 * The Invoke method is called as a result of an application request to run the Smart Contract
 * The calling application program has also specified the particular smart contract function to be called, with arguments
 */
func (s *SmartContract) Invoke(APIstub shim.ChaincodeStubInterface) sc.Response {
    function, args := APIstub.GetFunctionAndParameters()
    switch function {
    case "getAsset":
        return s.getAsset(APIstub, args)
    }
  
    return shim.Error("Invalid Smart Contract function name.")
}

func (s *SmartContract) getAsset(
 APIstub shim.ChaincodeStubInterface, args []string) sc.Response {
  
    if len(args) != 1 {
        return shim.Error("Incorrect number of arguments. Expecting 1")
    }

    assetAsBytes, err := APIstub.GetState(args[0])

    if err != nil || len(assetAsBytes) == 0 {
        return shim.Error(fmt.Sprintf("No asset with ID: %s", args[0]))
    }

    return shim.Success(s.getObjectAsBytes(assetLocalID, assetAsBytes))
}

func (s *SmartContract) getObjectAsBytes(
    identificator string, objectAsBytes []byte) []byte {
    
    var buffer bytes.Buffer
    buffer.WriteString("{\"Key\":")
    buffer.WriteString("\"")
    buffer.WriteString(identificator)
    buffer.WriteString("\"")
    buffer.WriteString(", \"Record\":")
    buffer.WriteString(string(objectAsBytes))
    buffer.WriteString("}")
    
    return buffer.Bytes()
}