[REQUIRED] Environment info

firebase-tools: 7.9.0

Platform: Linux (Fedora 29)

[REQUIRED] Test case

Request URLs are used in the SSR (angular-universal) for navigation it seems that there is a breaking change in how they are handled by function emulator.

The last version I verified that doesn't have this issue is firebase-tools@6.8.0.
From what I identified the problem seems to be related to request URLs. If I log the values I see

app.get('*', (req: express.Request, res: express.Response) => {

  
  console.log(req.url, req.baseUrl, req.originalUrl);
  //  '/en/contact' '/web/us-central1/ssr' '/web/us-central1/ssr/en/contact'

  res.render('web-index', { req, res });
});

But in case of the older versions of firebase-tools let's say the version 6.8.0, output for the same code will be '/en/contact', '', '/en/contact'.

[REQUIRED] Steps to reproduce

Create a firebase function with minimal express setup and log the request object.

[REQUIRED] Expected behavior

URLs probably shouldn't be prefixed by the function base.

As a quick fix, I'm using replacing the prefix with request.baseUrl as a base should represent the prefix, but I'm not sure if it is the case in every possible scenario.

app.get('*', (req: express.Request, res: express.Response) => {

  req.originalUrl = req.originalUrl.replace(req.baseUrl, '');

  res.render('web-index', { req, res });

});

Another fix that may be a nicer solution is to explicitly set the url string.
res.render('web-index', { req, res, url: req.url });

[REQUIRED] Actual behavior

URLs are prefixed by the function base. Router inside the universal rendering doesn't recognize the routes correctly and renders the default page.

As already mentioned in #1279 it seems like a breaking change that should be eighter corrected or documented.