Working with chaincode state using ChaincodeStubeInterface

working_with_cc_state.go

ct := ContractType{}

err := json.Unmarshal([]byte(args[0]), &req)
if err != nil {
    return shim.Error(err.Error())
}

key, err := stub.CreateCompositeKey(prefixContractType, []string{req.UUID})
if err != nil {
    return shim.Error(err.Error())
}

valAsBytes, err := stub.GetState(key)
if err != nil {
    return shim.Error(err.Error())
}
if len(valAsBytes) == 0 {
    return shim.Error("Contract Type could not be found")
}
err = json.Unmarshal(valAsBytes, &ct)
if err != nil {
    return shim.Error(err.Error())
}

ct.Active = req.Active
valAsBytes, err = json.Marshal(ct)
if err != nil {
    return shim.Error(err.Error())
}

err = stub.PutState(key, valAsBytes)
if err != nil {
    return shim.Error(err.Error())
}

return shim.Success(nil)