A video recording of the showcase can be found here: https://www.youtube.com/watch?v=Ldh-b4Hu5LE&feature=youtu.be
A product is tracked along the supply chain in this showcase. The supplier has a website (http://localhost:8000/supplier1) and can log product data with its associated timestamp to the public Ethereum network. The manufacturer has a website as well (http://localhost:8000/manufacturer). The manufacturer can fetch the already available product data from the Ethereum network to his/her local Hyperledger Fabric network. The manufacturer can add additional product data with its associated timestamp to the local Hyperledger Fabric network. The supplier as well as the manufacturer can query the product data on their respective networks at any time.
Access control has to be implemented in the Ethereum contract in the future if this showcase is used in prouction to ensure that only authorized suppliers can add product data.
These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.
The following prerequisites have to be installed to run Hyperledger Fabric 2.0 locally on your machine:
- Install docker
sudo apt-get install docker.io
sudo systemctl start docker
sudo systemctl enable docker
sudo usermod -a -G docker $USER
- Install docker-compose
sudo apt-get install docker-compose
- Install Hyperledger Fabric 2.0 binaries
curl -sSL https://bit.ly/2ysbOFE | bash -s -- 2.0.0
- Install npm and node.js
curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -
sudo apt-get install -y nodejs
sudo apt-get install build-essential
- Clone this repository
- Install required node dependencies from the package.json file in the folder "website"
cd Showcase_of_blockchain_interoperability_in_the_field_of_supply_chain/website
npm install
- Finally start the Hyperledger Fabric network and website
cd Showcase_of_blockchain_interoperability_in_the_field_of_supply_chain
sudo ./start_Network.sh
The following prerequisites have to be installed to interact with Ethereum through your Chrome web browser:
- MetaMask as a browser plug-in
- Create an account in MetaMask
- Select "Rinkeby Test Network" in the drop-down menu in MetaMask
- Get some free Test Ether for the Rinkeby Network from an online faucet
-
cd Showcase_of_blockchain_interoperability_in_the_field_of_supply_chain
-
sudo ./start_Network.sh
The following smart contract is installed on the Hyperledger Fabric 2.0 network but it can be replaced with any other smart contract code. The website interacts with the Hyperledger Fabric network through the Node Fabric SDK at the two backend files "Query_Hyperledger.js" and "Invoke_Hyperledger.js".
package main
import (
"fmt"
"strconv"
"encoding/json"
"github.com/hyperledger/fabric-chaincode-go/shim"
sc "github.com/hyperledger/fabric-protos-go/peer"
)
// Define the Smart Contract structure
type SmartContract struct {
}
/*
* 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 {
// Retrieve the requested Smart Contract function and arguments
function, args := APIstub.GetFunctionAndParameters()
// Route to the appropriate handler function to interact with the ledger appropriately
if function == "store" {
return s.store(APIstub, args)
} else if function == "Init" {
return s.Init(APIstub)
} else if function == "retrieve" {
return s.retrieve(APIstub, args)
} else {fmt.Println("Invalid Smart Contract function name.")
return shim.Error("Invalid Smart Contract function name.")}
}
type unit struct {
Value string `json:"value"`
}
func (s *SmartContract) retrieve(APIstub shim.ChaincodeStubInterface, args []string ) sc.Response {
var iterator,err=APIstub.GetStateByPartialCompositeKey("key~timestamp", []string{args[0]})
if err != nil {
fmt.Printf("error,error")
return shim.Error(err.Error())
}
defer iterator.Close()
total_result:="\"{"
// Iterate through result set
var i int
var unitJSON unit
for i = 0; iterator.HasNext(); i++ {
responseRange, err := iterator.Next()
if err != nil {
return shim.Error(err.Error())
}
_, compositeKeyParts, err := APIstub.SplitCompositeKey(responseRange.Key)
if err != nil {
return shim.Error(err.Error())
}
returnedTimestamp := compositeKeyParts[1]
err = json.Unmarshal(responseRange.Value, &unitJSON)
if err != nil {
jsonResp := "{\"Error\":\"Failed to decode JSON. \"}"
return shim.Error(jsonResp)
}
total_result=total_result+"\\\"Object"+strconv.Itoa(i)+"\\\":{\\\"key\\\":\\\""+args[0]+"\\\",\\\"time\\\":\\\""+returnedTimestamp+"\\\",\\\"value\\\":\\\""+unitJSON.Value+"\\\"}"
if (iterator.HasNext()){
total_result=total_result+","
} else {
total_result=total_result+",\\\"length\\\":\\\""+strconv.Itoa(i+1)+"\\\""
}
}
total_result=total_result+"}\""
return shim.Success([]byte(total_result))
}
func (s *SmartContract) store(APIstub shim.ChaincodeStubInterface, args []string ) sc.Response {
var compositeKey, err=APIstub.CreateCompositeKey("key~timestamp",[]string{args[0],args[1]})
if err != nil {
return shim.Error(err.Error())
}
APIstub.PutState(compositeKey, []byte(args[2]));
return shim.Success(nil)
}
func (s *SmartContract) Init(APIstub shim.ChaincodeStubInterface ) sc.Response {
return shim.Success(nil)
}
func main() {
//Create a new Smart Contract
err := shim.Start(new(SmartContract))
if err != nil {
fmt.Printf("Error creating new Smart Contract: %s", err)
}
}The following solidity contract is deployed on the Rinkeby Testnet (Ethereum) but it can be replaced with any other solidity contract code. The website interacts with the Ethereum network through the web3.js library at the frontend files "manufacturer.html" and "supplier1.html" .
This is the link to the contract on the Rinkeby test net: https://rinkeby.etherscan.io/address/0x78fAF84E08ed839d3Fde0753C07E5C505f1a3F93
pragma solidity >= 0.4.22 < 0.7.0;
contract Storage {
struct Action{
uint256 timestamp;
string action_happening;
}
mapping(string => Action[]) assets;
function store(string memory _key, string memory _value) public {
assets[_key].push(Action(now, _value));
}
function length(string memory _key) public view returns(uint256){
return assets[_key].length;
}
function retrieve(string memory _key, uint256 index) public view returns (uint256, string memory){
return (assets[_key][index].timestamp, assets[_key][index].action_happening);
}
}