Cannot enable events URL in Slack API using Bolt app

[brendanmckeown]

Description

I am running a Bolt app locally, proxied with ngrok, and the Slack API Enable Subscriptions page will not verify the Events Request URL. In the ngrok inspector, it looks like the response is correct, but on the Slack API page, I receive the error "Your URL didn't respond with the value of the challenge parameter." but no other information.

What type of issue is this? (place an x in one of the [ ])

• bug
• enhancement (feature request)
• question
• documentation related
• testing related
• discussion

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

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Bug Report

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Reproducible in:

package version:
1.5.0

node version:
12.13.1

OS version(s):
macOS 10.13.6

Steps to reproduce:

I am following the "Getting Started" instructions on this page

1. On Slack API page, create a new Slack app for a workspace, then create a new bot user
2. Copy the signing secret and bot auth token
3. On local machine, setup new Bolt project:

• Create directory
• npm init
• npm i -S @slack/bolt
• set environment variables copied above
• create app.js and paste contents from instructions
• start app

4. On local machine, start ngrok to proxy http port 3000
5. On Slack API Events Subscriptions page, enable events, then in the Request URL field, post the ngrok https URL followed by /slack/events path.

Expected result:

Events URL is verified

Actual result:

Bolt app responds to event URL verification request, but the Slack API page is unable to verify the URL and displays the error, "Your URL didn't respond with the value of the challenge parameter."

Attachments:

Slack API Events URL verification error:

Request in ngrok inspector:

Response in ngrok inspector:

[aoberoi]

It seems like Bolt did respond to the challenge request as it is meant to be handled. I tried reproducing this myself, and things worked as expected.

Are you still having this issue? It's possible it was just a momentary problem that has been resolved since.

[brendanmckeown]

Thanks @aoberoi – the issue stopped happening yesterday, without any changes made on my side.

[dgadelha]

If anyone else struggles with an issue similar to that, except where the app never answers the request, bolt's middleware should come before any other, like express.json().

Bad:

app.use(express.json());
app.use(receiver.app);

Good:

app.use(receiver.app);
app.use(express.json());