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March 5, 2018 08:48
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Express raw body for Facebook Hub Signature validation
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| const express = require('express'); | |
| const bodyParser = require('body-parser'); | |
| const crypto = require('crypto'); | |
| const app = express(); | |
| // Use json body parser when content is `application/json` type and request headers does not include `x-hub-signature` | |
| app.use(bodyParser.json({ | |
| type: req => req.headers['content-type'] == 'aplication/json' && !req.headers['x-hub-signature'] | |
| })); | |
| // Use raw body parser when headers include `x-hub-signature` | |
| app.use(bodyParser.raw({ | |
| type: req => !!req.headers['x-hub-signature'] | |
| })); | |
| app.use(bodyParser.urlencoded({ extended: true })); | |
| const verificationToken = 'your-token'; | |
| const clientSecret = 'your-app-secret'; | |
| // Hub signature verification middleware | |
| const verifyHubSignature = function (req, res, next) { | |
| const signature = req.headers['x-hub-signature']; | |
| if(signature !== undefined && Buffer.isBuffer(req.body)) { | |
| const hmac = crypto.createHmac('sha1', clientSecret); | |
| hmac.update(req.body); | |
| const expectedSignature = 'sha1=' + hmac.digest('hex'); | |
| if(expectedSignature !== signature) { | |
| res.status(400).send('Invalid signature'); | |
| } else { | |
| next(); | |
| } | |
| } else { | |
| next(); | |
| } | |
| } | |
| app.use('/subscriptions', verifyHubSignature, function(req, res) { | |
| // Authorize subscription | |
| if(req.query['hub.mode'] == 'subscribe' && req.query['hub.verify_token'] == verificationToken) { | |
| res.status(200).send(req.query['hub.challenge']); | |
| // Subscription update | |
| } else if(req.headers['x-hub-signature']) { | |
| console.log('verified'); | |
| res.sendStatus(200); | |
| } else { | |
| res.sendStatus(400); | |
| } | |
| }); |
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LINE8 "aplication" should be "application"