[BUG] Cannot validate webhook

Bug Report

Describe the bug There is an error during Webhook validation (the code used to work previously) This happened in middleware when /webhook was called

To Reproduce

Steps to reproduce the behavior: 0. You may or may not use the code from my repo (https://github.com/gie3d/nonglinebot)

1. Used node line bot sdk and created a /webhook that looks like this

app.post('/webhook', line.middleware(config), (req, res) => {
    Promise
        .all(req.body.events.map(handleEvent))
        .then((result) => res.json(result));
});

1. Test webhook from Line developers website and check the log

2020-06-15T08:15:23.078099+00:00 heroku[router]: at=info method=POST path="/webhook" host=qline2020.herokuapp.com request_id=5b01db7e-532a-436b-8ba5-c55993174f61 fwd="203.104.156.74" dyno=web.1 connect=1ms service=23ms status=500 bytes=404 protocol=https
2020-06-15T08:15:23.079280+00:00 app[web.1]: TypeError [ERR_INVALID_ARG_TYPE]: The "data" argument must be of type string or an instance of Buffer, TypedArray, or DataView. Received an instance of Object
2020-06-15T08:15:23.079323+00:00 app[web.1]:     at Hmac.update (internal/crypto/hash.js:82:11)
2020-06-15T08:15:23.079324+00:00 app[web.1]:     at Object.validateSignature [as default] (/app/node_modules/@line/bot-sdk/dist/validate-signature.js:14:69)
2020-06-15T08:15:23.079325+00:00 app[web.1]:     at _middleware (/app/node_modules/@line/bot-sdk/dist/middleware.js:36:42)
2020-06-15T08:15:23.079326+00:00 app[web.1]:     at processTicksAndRejections (internal/process/task_queues.js:97:5)

The error seems to happen in validate-signature and the type of data seems to be incorrect but I can’t investigate any further.

Expected behavior There should be no error

Environment (please complete the following information):

• OS: Mac OS X 10.15.5
• Node.js 12.6.0
• line-bot-sdk-nodejs 6.8.4

[gie3d]

Thanks @xingoxu @EriecTanijaya, it really was because of the body-parser. My apologise, the code I pushed to heroku was a little different from the git as I didn’t push it to my github repo 😥

Changing from

app.use(bodyParser.json());
app.use('/webhook', line.middleware(config));

app.post('/webhook', (req, res) => {
	Promise.all(req.body.events.map(handleLineWebHook)).then((result) => res.json(result));
});

to

app.use('/webhook', line.middleware(config));
app.use(bodyParser.json());

app.post('/webhook', (req, res) => {
	Promise.all(req.body.events.map(handleLineWebHook)).then((result) => res.json(result));
});

as suggested in https://line.github.io/line-bot-sdk-nodejs/guide/webhook.html#build-a-webhook-server-with-express did solve the problem.

Many thanks 👍

[xingoxu]

Are you using bodyParser before initializing middleware? https://line.github.io/line-bot-sdk-nodejs/guide/webhook.html#build-a-webhook-server-with-express