Request URLs are prefixed with the function "path"

[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.

[samtstern]

Ok I finally got around to taking another look at this one. Here’s the function I wrote to reproduce:

const functions = require('firebase-functions');
const express = require('express');

const app = express();

app.get('*', (req, res) => {
  console.log();
  res.json({
    url: req.url, 
    baseUrl: req.baseUrl, 
    originalUrl: req.originalUrl
  })
});

exports.app = functions.https.onRequest(app);

In Emulator

$ http http://localhost:5001/ota-fir-dumpster/us-central1/app
HTTP/1.1 200 OK
connection: keep-alive
content-length: 107
content-type: application/json; charset=utf-8
date: Wed, 30 Dec 2020 12:38:10 GMT
etag: W/"6b-SnHfCzo9jWjTQGgDAwDu81tuOmE"
x-powered-by: Express

{
    "baseUrl": "/ota-fir-dumpster/us-central1/app",
    "originalUrl": "/ota-fir-dumpster/us-central1/app",
    "url": "/"
}

$ http http://localhost:5001/ota-fir-dumpster/us-central1/app/path/foo
HTTP/1.1 200 OK
connection: keep-alive
content-length: 124
content-type: application/json; charset=utf-8
date: Wed, 30 Dec 2020 12:38:16 GMT
etag: W/"7c-lwuBVeZMy6349B2FVhCt3+PGptU"
x-powered-by: Express

{
    "baseUrl": "/ota-fir-dumpster/us-central1/app",
    "originalUrl": "/ota-fir-dumpster/us-central1/app/path/foo",
    "url": "/path/foo"
}

In Production

$ http https://us-central1-ota-fir-dumpster.cloudfunctions.net/app
HTTP/1.1 200 OK
Alt-Svc: h3-29=":443"; ma=2592000,h3-T051=":443"; ma=2592000,h3-Q050=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,quic=":443"; ma=2592000; v="46,43"
Content-Length: 42
Content-Type: application/json; charset=utf-8
Date: Wed, 30 Dec 2020 12:40:03 GMT
Etag: W/"2a-2r6K6VdplGUiLl7XTpwje2YJ12g"
Function-Execution-Id: gxhndtuf9dlb
Server: Google Frontend
X-Cloud-Trace-Context: 5e85c00da8a0563a1076de38ecb54714;o=1
X-Powered-By: Express

{
    "baseUrl": "",
    "originalUrl": "/",
    "url": "/"
}

$ http https://us-central1-ota-fir-dumpster.cloudfunctions.net/app/path/foo
HTTP/1.1 200 OK
Alt-Svc: h3-29=":443"; ma=2592000,h3-T051=":443"; ma=2592000,h3-Q050=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,quic=":443"; ma=2592000; v="46,43"
Content-Length: 58
Content-Type: application/json; charset=utf-8
Date: Wed, 30 Dec 2020 12:40:09 GMT
Etag: W/"3a-TJpl1HpUobjuBCL03i7kbgn4ABk"
Function-Execution-Id: gxhndyw5iapw
Server: Google Frontend
X-Cloud-Trace-Context: 89a464a3ad411803131091be405c84f5
X-Powered-By: Express

{
    "baseUrl": "",
    "originalUrl": "/path/foo",
    "url": "/path/foo"
}

So it looks like url is correct but baseUrl and originalUrl both contain an unnecessary prefix of /ota-fir-dumpster/us-central1/app … I’ll look at how to remove that now.

[samtstern]

@charles-allen I can totally see your use cases but our goal here is in this repo is simple: create emulators which locally match the behavior of Google Cloud Functions in production.

I can’t offer any insight as to why GCF paths are the way they are, that sort of decision is a few years old and was made before these emulators existed! Changing it would be really disruptive so I think we’ll have to live with the current behavior.