Express application level middleware and cookieSession, need to add in parameter from prior middleware

Question

I am trying to pass a parameter from one middleware to the next. The first middleware is just storing a secret key in req.cookieKey. The second middleware is using express's cookie-session. Normally I would know how to do this but something is breaking when I try to return cookieSession( in the second middleware. See my code below and an example on codesandbox.io linked at the bottom.

This middleware comes first:

const asyncMiddleware = async (req,res,next) => {
    const data = await SecretKeeper.getCredentialPair('cookie');
    req.cookieKey = data.credential;
    next()
  }

In my routes I am calling:

    //get key from SecretKeeper to encrypt cookie that will be set in next middleware
    app.use(asyncMiddleware);

    //set cookie middleware, use key from SecretKeeper to sign and verify cookie
    app.use((req, res, next) => {

        return cookieSession({
            name: 'MySession',
            keys: [req.cookieKey],

            // Cookie Options
            maxAge: .30 * 60 * 60 * 1000 // 30 min
        })
    })

It works if I don't try to add in the key from SecretManager (the first middleware) and I remove the extra function layer (req, res, next) => from my second middleware.

I was hoping I could use the req.cookieKey that I set earlier and then just return the cookieSession function but that doesn't seem to be working. I tested to make sure that I can get the req.cookieKey when I am setting cookie middleware but for some reason I can't get the cookieSession to work correctly. Anyone have any suggestions? I have included the working version without passing the parameter here: https://codesandbox.io/s/l2lw7499q9

Answer 1

cookieSession(options) returns function(req, res, next), so you must run it:

app.use((req, res, next) => {

    cookieSession({
        name: 'MySession',
        keys: [req.cookieKey],

        // Cookie Options
        maxAge: .30 * 60 * 60 * 1000 // 30 min
    })(req, res, next) //here
})