We are looking for a way to create predictable preview URLs for our Firebase Hosting preview channels. We require this functionality to whitelist these URLs for accessing a Cloud CDN authenticated content bucket. Currently, the preview channel URLs generated by Firebase Hosting include a random hash (SITEID--CHANNELID-RANDOM_HASH.web.app), which makes them unpredictable.

The solutions we have devised include:

• Replace the random hash for something like https://<PROJECT_ID>--pr-<PULL_REQUEST_NUMBER>.web.app
• Make the preview channel URL persistent when deploying new versions.