Help with verify EventSub signature

BarryCarlyon · November 24, 2020, 2:10pm

NodeJS example of EventSub Sig verficiation

Speifically line 38

BarryCarlyon/twitch_misc/blob/main/eventsub/handlers/nodejs/receive.js#L38

    
      
          http.listen(config.port, function() {
              console.log('Server raised on', config.port);
          });
          
          
// Middleware!
          // Express allows whats called middle ware
          // it runs before (or after) other parts of the route runs
          app.use(express.json({
              verify: function(req, res, buf, encoding) {
                  // is there a hub to verify against
                  req.twitch_eventsub = false;
                  if (req.headers && req.headers.hasOwnProperty('twitch-eventsub-message-signature')) {
                      req.twitch_eventsub = true;
          
          
            // id for dedupe
                      let id = req.headers['twitch-eventsub-message-id'];
                      // check age
                      let timestamp = req.headers['twitch-eventsub-message-timestamp'];
                      // extract algo and signature for comparison
                      let [ algo, signature ] = req.headers['twitch-eventsub-message-signature'].split('=');

I have it setup the same way for EventSub as Webhooks