Source: https://fyno.docs.pageloop.ai/sd-ks/in-app/react-in-app-sdk

# React In-App SDK

The In-App React SDK is a powerful tool that allows you to seamlessly integrate Fyno's notification center into your React-based applications. With this SDK, you can enhance your user's experience by providing them with a feature-rich and customisable notification center.

## Installation

To get started with In-App React SDK, you'll need to install it using [NPM](https://www.npmjs.com/package/@fyno/inapp-react)

```bash title="npm"
npm install @fyno/inapp-react
```

## Usage

Before you dive into using the In-App Notification Center, there are some prerequisites you need to fulfill. You must ensure you have the necessary information and generate an HMAC signature.

### Prerequisites

Before you start, make sure you have the following information ready

- **Workspace ID (WSID)**: You can find your workspace ID on your Fyno App > [API Keys](https://app.fyno.io/settings#api-keys) page.
- **Integration Token**: Obtain the integration token from the Fyno App > [Integrations](https://app.fyno.io/integrations) page.
- **User ID**: This should be a unique identifier for the currently logged-in user. This user ID is crucial for Fyno to send specific notifications to the right users.

### HMAC Signature Generation

The HMAC signature is essential for ensuring the security and integrity of your notifications. Here are examples of how to generate the HMAC signature in various programming languages

#### Node

```js title="Node" wordWrap
import crypto from 'crypto'; //module
//or
// const crypto = require('crypto') //commonjs
const signature = crypto
  .createHmac('sha256', 'WSID' + 'INTEGRATION_TOKEN')
  .update('USER_ID')
  .digest('hex');
```

#### JavaScript

```js title="JavaScript" wordWrap
const CryptoJS = require('crypto-js'); //commonjs
//or
//import CryptoJS from "crypto-js";//module
const secretKey = 'WSID' + 'INTEGRATION_TOKEN';
const userId = 'USER_ID';

const signature = CryptoJS.HmacSHA256(userId, secretKey).toString(CryptoJS.enc.Hex);
```

#### Python

```python title="Python" wordWrap
import hashlib
import hmac

secret_key = b'WSID'+b'INTEGRATION_TOKEN'
user_id = 'USER_ID'

signature = hmac.new(secret_key, user_id.encode('utf-8'), hashlib.sha256).hexdigest()
```

#### Java

```java title="Java" wordWrap
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;

public class SignatureExample {

    public static void main(String[] args) throws Exception {
        String secretKey = "WSID" + "INTEGRATION_TOKEN"; // Concatenate the secret key
        String userId = "USER_ID";

        // Create a new instance of the HmacSHA256 algorithm
        Mac mac = Mac.getInstance("HmacSHA256");
        SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
        mac.init(secretKeySpec);

        // Compute the hash
        byte[] hash = mac.doFinal(userId.getBytes(StandardCharsets.UTF_8));

        // Convert the hash to a hexadecimal string
        StringBuilder hexString = new StringBuilder();
        for (byte b : hash) {
            String hex = String.format("%02x", b);
            hexString.append(hex);
        }

        String signature = hexString.toString();
    }

}

```

#### Go

```go title="Go" wordWrap
package main

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
)

func main() {
	secretKey := "WSID"+"INTEGRATION_TOKEN"
	userId := "USER_ID"

	key := []byte(secretKey)
	data := []byte(userId)

	// Create an HMAC-SHA256 hasher
	hasher := hmac.New(sha256.New, key)

	// Write the data to the hasher
	_, err := hasher.Write(data)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	// Get the resulting hash as bytes
	hash := hasher.Sum(nil)

	// Convert the hash to a hexadecimal string
	signature := hex.EncodeToString(hash)
}
```

#### PHP

```php title="PHP" wordWrap
$secretKey = 'WSID'.'INTEGRATION_TOKEN';
$userId = 'USER_ID';

$signature = hash_hmac('sha256', $userId, $secretKey);
```

#### Ruby

```ruby title="Ruby" wordWrap
require 'openssl'

secret_key = 'WSID'+'INTEGRATION_TOKEN'
user_id = 'USER_ID'

signature = OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha256'), secret_key, user_id)
```

#### C\#

```csharp title="C#" wordWrap
using System;
using System.Security.Cryptography;
using System.Text;

class Program
{
    static void Main()
    {
        string secretKey = "WSIDINTEGRATION_TOKEN";
        string userId = "USER_ID";

        using (HMACSHA256 hmac = new HMACSHA256(Encoding.UTF8.GetBytes(secretKey))
        {
            byte[] hash = hmac.ComputeHash(Encoding.UTF8.GetBytes(userId));
            string signature = BitConverter.ToString(hash).Replace("-", "").ToLower();
        }
    }
}
```

> [!WARNING]
>
> **Watch out when generating HMAC Signatures!**
>
> Avoid generating the signature in the frontend, as it can expose your Integration token. Always generate the token securely in the backend or middleware.

### SDK Initialisation

To use the SDK in your React application, you can import `FynoInappCenter` and configure it as follows

#### Option 1

```jsx title="Option 1" wordWrap
import { FynoInappCenter } from '@fyno/inapp-react'

class Example extends Component {
  // Incoming notification listener
  const onMessageReceived = () => {
  //Handle incoming notification data
  }
  const config = {
    mode: 'THEME_MODE', // Choose between 'light' or 'dark'
    user: 'USER_ID',
    workspace: 'WSID',
    integration: 'INTRGRATION_ID',
    signature: 'signature',
    themeConfig: {
      logo: 'LINK_TO_BRAND_LOGO',
      primary: 'PRIMARY_COLOR',
      lightBackground: 'LIGHT_THEME_BACKGROUND_COLOR',
      darkBackground: 'DARK_THEME_BACKGROUND_COLOR',
      header: 'Notifications', // Optional: If specified, a header will be shown
    },
    notificationSettings: {
      sound: 'LINK_TO_NOTIFICATION_SOUND',
      invertTheme: false, // Set to true for inverted theme
    },
    onMessageReceived
  }

  render() {
    return <FynoInappCenter {...config} />
  }
}

```

#### Option 2

```jsx title="Option 2" wordWrap
import { FynoInappCenter } from '@fyno/inapp-react'

class Example extends Component {
  // Incoming notification listener
  const onMessageReceived = () => {
  //Handle incoming notification data
  }
  const themeConfig = {
    logo: 'LINK_TO_BRAND_LOGO',
    primary: 'PRIMARY_COLOR',
    lightBackground: 'LIGHT_THEME_BACKGROUND_COLOR',
    darkBackground: 'DARK_THEME_BACKGROUND_COLOR',
  }

  const notificationSettings = {
    sound: 'LINK_TO_NOTIFICATION_SOUND',
    invertTheme: false, // Set to true for inverted theme
  }

  render() {
    return (
      <FynoInappCenter
        theme="light"
        user="{userid}"
        workspace="{workspace_id}"
        integration="{integration_id}"
        signature="{signature generated from backend}"
        themeConfig={themeConfig}
        notificationSettings={notificationSettings}
        onMessageReceived = {onMessageReceived}
      />
    )
  }
}
```

Feel free to customise the configuration to match your application's requirements.

That's it! You're now ready to integrate and use Fyno's In-App Notification Center in your React application.