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 securely listen for and handle webhook events.
Webhook Payload Structure
Each webhook sent by Extracta.ai will include two primary fields in the request body:
event â A string identifying the type of event (e.g., extraction.processed, extraction.failed).
A secret key obtained from the Extracta.ai dashboard
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
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 signatureRequest = req.headers["x-webhook-signature"];
const resultString = JSON.stringify(req.body.result);
const signature = crypto.createHmac('sha256', secret.replace('E_AI_K_', '')).update(resultString).digest('base64');
if (signature !== signatureRequest) {
return res.status(401).send({
message: "Webhook is not properly signed"
});
}
return next();
}
// Webhook endpoint
app.post('/webhook', validateSignature, async (req, res) => {
try {
let { event, result } = req.body;
switch (event) {
case "extraction.processed":
console.log("extraction.processed", result);
break;
case "extraction.edited":
console.log("extraction.edited", result);
break;
case "extraction.confirmed":
console.log("extraction.confirmed", result);
break;
case "extraction.failed":
console.log("extraction.failed", result);
break;
default:
console.log("unknown event", event);
break;
}
return res.send({
event: event,
message: "Webhook received",
timestamp: new Date().toISOString()
})
} catch (error) {
console.error("Error processing webhook", error);
return res.status(500).send({
message: "Error processing webhook",
error: error.message,
timestamp: new Date().toISOString()
});
}
})
app.listen(port, () => console.log(`Server listening on port ${port}!`))
Step 3: Test Your Webhook Listener
Once your webhook listener is set up, test it by triggering events from Extracta.ai. Confirm that:
The signature is validated correctly.
The event is identified.
The result is handled based on the event type.
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.
