how to attach middleware like express.static ?

[dcsan]

Description

I want to send some static files from an app that's also using Bolt.

as per the docs here I can get the bolt "router" but can't use the normal method to attach express.static middleware.

    const receiver = new ExpressReceiver({ signingSecret: AppConfig.signingSecret });
    app.use(eventLogger) // my own custom middleware

    // but this doesnt work
    // app.use('/cdn', express.static('/cdn'))

currently I have to wire it up with manual send file:

    receiver.router.get('/cdn/*', (req, res) => {
      logger.log('cnd get', req.path)
      const fp = path.join(__dirname, '../../../', req.path)
      res.contentType('image/jpeg');
      res.sendFile(fp);
    })

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

• [ ] bug
• [X] enhancement (feature request)
• [X] question
• [X] documentation related
• [ ] testing related
• [x] discussion

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

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

[seratch]

// but this doesnt work // app.use('/cdn', express.static('/cdn'))

receiver.app.use('/cdn', express.static('/cdn')) should work for you. As App should not provide any Express.js specific methods or interfaces, we won't add the functionalities to App. You can directly access Express by either receiver.router or receiver.app.

See also: https://github.com/slackapi/bolt-js/issues/191

[seratch]

@dcsan I believe I've already answered this question. Could you close this issue?

[dcsan]

yep this worked, thanks!

[jzaynal]

@seratch using a custom ExpressReceiver as the receiver property into App is not always an option. As soon as you provide the receiver option the built-in Bolt listeners aren't usable. I am currently using the built-in listeners and endpoints for OAuth, events and actions, so want to keep using those but at the same time also configure a static files endpoint.

How can I do that without losing all the OAuth and event listeners that come with Bolt?

Bolt for JavaScript does not support OAuth for custom receivers. If you’re implementing a custom receiver, you can use our Slack OAuth library, which is what Bolt for JavaScript uses under the hood.

https://slack.dev/bolt-js/concepts#authenticating-oauth