How to use the Webhook

Webhooks allow you to receive real-time notifications of events happening within your Extracta.ai extractions. This section will guide you through setting up a Node.js server with Express to listen for and handle webhook events securely.

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Prerequisites

• Node.js installed on your server

• An Express.js application

• A secret key obtained from the Extracta.ai dashboard

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Step 1: Set Up Your Server

First, ensure you have Express and the necessary packages installed in your project. If not, you can install them using npm:

npm install express body-parser crypto --save

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Step 2: Implement Webhook Endpoint

Create a basic HTTP server with Express to listen for webhook POST requests. Use the following code snippet as a starting point:

server.js

const express = require('express');
const crypto = require('crypto');
const bodyParser = require('body-parser');

const app = express();
const port = 4000;

app.use(bodyParser.json());

// Your webhook secret key from the dashboard
const secret = 'secretKey';

// Middleware to validate the webhook signature
function validateSignature(req, res, next) {
  const sigHeader = req.headers["x-webhook-signature"];

  const signature = crypto.createHmac('sha256', secret.replace('E_AI_K_', '')).update(req.body.result).digest('base64');

  if (signature !== sigHeader) {
    return res.status(401).send({ message: "Webhook is not properly signed" })
  }

  next()
}

// Webhook endpoint
app.post('/webhook', validateSignature, (req, res) => {
  console.log('Webhook received:', req.body);
  
  // Process the webhook payload as needed
  // ...

  res.send({ message: "Webhook received" })
})

app.listen(port, () => console.log(`Server listening on port ${port}!`))

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Step 3: Test Your Webhook Listener

After setting up your webhook listener, test it by sending a simulated files. Ensure your server validates the signature and processes the event correctly.

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By following these steps, you can securely set up your application to receive and process webhook events from Extracta.ai, enabling real-time updates and actions based on the events transmitted to your endpoint.