Hyperledger Setup

Prerequisites

1. Go
   For go installation use the following commands:

   wget https://go.dev/dl/go1.19.9.linux-amd64.tar.gz
   sudo tar -C /usr/local -xzf go1.19.9.linux-amd64.tar.gz

   Add Go to PATH

   echo "export PATH=$PATH:/usr/local/go/bin" >> ~/.bashrc
   source ~/.bashrc

   Verify installation

   go version

2. Install Docker and Docker Compose

   Install Docker Desktop from docker website or docker cli.

3. Install Node.js and npm

   For installation of node and npm use following commands:

   Update package list and install build tools

   sudo apt-get update
   sudo apt-get install -y build-essential

   Install Node.js (latest LTS)

   curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash -
   
   sudo apt-get install -y nodejs

   Verify installation

   node -v
   npm -v

Download and Set Up Hyperledger Fabric:

Clone Fabric Samples and Binaries:

Create a directory for your Fabric projects

mkdir ~/hyperledger-fabric
cd ~/hyperledger-fabric

Download Fabric samples, binaries, and Docker images

curl -sSL https://raw.githubusercontent.com/hyperledger/fabric/main/scripts/bootstrap.sh | bash -s

React and Go App Setup

React Setup

1. Folder Structure Setup

    cd ~/hyperledger-fabric/fabric-samples
    mkdir my-app
    cd my-app

2. Initialize the React Frontend

    npx create-react-app frontend
    cd frontend

   To install dependencies required for making API requests:

   npm install axios

3. Navigate to src folder

   cd src

4. Open App.js file and write the following code in the file

   import React from 'react';
    import axios from 'axios';
   
    function App() {
        const handleClick = async () => {
            try {
            const response = await axios.get('http://localhost:8080/api');
            console.log(response.data);
            } catch (error) {
            console.error('Error making request:', error);
            }
        };
   
        return (
            <div className="App">
            <h1>React + Go Backend</h1>
            <button onClick={handleClick}>Click Me</button>
            </div>
        );
    }
   
    export default App;

5. Run the React Frontend

   npm start

   This will serve your React app at http://localhost:3000.

Go Setup

1. Navigate back to the my-app folder and create a backend directory for the Go server:

   cd ..
   mkdir backend
   cd backend

2. Initialize the Go module:

   go mod init my-app/backend

3. Create file and Write the Go Backend Code:

   touch main.go

   Open the file and write the following code:

   package main
   
    import (
        "fmt"
        "log"
        "net/http"
    )
   
    func handleRequest(w http.ResponseWriter, r *http.Request) {
        fmt.Println("Button clicked, request received!")
        w.Write([]byte("Backend response: Success!"))
    }
   
    func main() {
        http.HandleFunc("/api", handleRequest)
        fmt.Println("Backend running at http://localhost:8080")
        log.Fatal(http.ListenAndServe(":8080", nil))
    } 

4. Run the Go Backend

   go run main.go

   This will start your Go backend at http://localhost:8080.

Click the "Click Me" button. If successful, you should see the message “Button clicked, request received!” printed in your terminal where the Go server is running.

Errors

If you see any cors issues you can do the following:

1. In your Go backend directory, run:

   go get github.com/rs/cors

2. Update Your Go Code in main.go:

   package main
   
    import (
        "fmt"
        "log"
        "net/http"
        "github.com/rs/cors"
    )
   
    func handleRequest(w http.ResponseWriter, r *http.Request) {
        fmt.Println("Button clicked, request received!")
        w.Write([]byte("Backend response: Success!"))
    }
   
    func main() {
        mux := http.NewServeMux()
        mux.HandleFunc("/api", handleRequest)
   
        // Enable CORS for all origins
        c := cors.New(cors.Options{
            AllowedOrigins:   []string{"*"},
            AllowCredentials: true,
        })
   
        handler := c.Handler(mux)
        fmt.Println("Backend running at http://localhost:8080")
        log.Fatal(http.ListenAndServe(":8080", handler))
    }

3. Run again:

   go run main.go

Hopefully, this will resolve those errors.