Parsing a Marketing Cloud JWT in Node.js

Question

I'm experiencing an issue where in once execute end point is being run, It returns an error name: 'JsonWebTokenError', message: 'jwt malformed', I already have an environment variable using the JWT Signing Secret of my installed package.

This is a sample JWT Signing Secret

75VNnlc3AeYUX3whWaHk6ApJsBM19p6ZK_ZMXbK7c2GwWxyMcMxnxDVZGarJSNCc7P6ZTAaLaq7droBNIhchXZmx9X9hCKDDB6Gd5rOmzmg5DT_U1KzCMGxrmR2B6Pfwr_VMENNhEeyRgVVO7jPKd-q-Gp70rhcUKlE8CoCttAmtu8QM8brK8KW5Q9t1z9VSSeJp6dNvV6GKO83LQQfXlMP6ApHPR7SUWtm3KFdq1Larah7QtfLgnuziXZpGXA2

This is my

Execute method

exports.execute = function (req, res) {//console.log("execute function!!!");


console.log("EXECUTE HAS BEEN RUN");
console.log('KEY - > ' + process.env.JWT_KEY);
JWT(req.body, process.env.JWT_KEY, (err, decoded) => {

    // verification error -> unauthorized request
    if (err) {
        console.error(err);
        return res.status(401).end();
    }


    if (decoded && decoded.inArguments && decoded.inArguments.length > 0) {
        console.log('##### decoded ####=>', decoded);

        // decoded in arguments

    } else {
        console.error('inArguments invalid.');
        return res.status(400).end();
    }

});
console.log("end execute function!!!");

};

 This is my Decoder

    'use strict';

module.exports = (body, secret, cb) => {
    if (!body) {
        return cb(new Error('invalid jwtdata'));
    }

    require('jsonwebtoken').verify(body.toString('utf8'), secret, {
        algorithm: 'HS256'
    }, cb);
};

btw I'm using azure as a host for my web app.

Blockquote

Another question for my config.json is it allright if I don't have any inArguments since I can get the value from the incoming data associated with the entry event

Answer 1

1) Try to add body parser to your express server:

const app = express();
app.use(require('body-parser').raw({
   type: 'application/jwt'
}));

2) Regarding getting data from entry event source check my answer here: Get the name of the Data Extension you are working with : Custom Activity