How do you verify a Firebase Function?

Question

I'd like to add a webhook to a Google Cloud PubSub push subscription. My endpoint for the webhook url is a Firebase Function. To post to my Firebase endpoint, I must verify the domain.

My problem is that Firebase Functions don't seem to have a way to statically host a single website. Firebase hosting happens in an entirely different domain.

What I have (from Firebase Hosting):

https://[PROJECT-ID].firebaseapp.com/[GOOGLE-FILE].html

What I need (from Firebase Functions):

https://us-central1-[PROJECTID].cloudfunctions.net/[Google-FILE].html

Answer 1

I solved this by using express.static on a folder containing Google's HTML to be verified in my "./functions" directory.

Google really ought to consider allowing their static site hosting to optionally deploy to a specified route in a functions domain, rather than purely through a separate domain.

Something like the following:

...
constructor() {
    this.express = express();

    // place your google verification HMTL file in the directory to expose
    // in my case, 'www'
    this.express.use(express.static(join(__dirname, '../..', 'www')));

Then deploy your function.