Description

Fixes #3097

Node fetch attempts to make life easier, but in fact changes behavior that's defined in the spec and doesn't currently document it: https://github.com/node-fetch/node-fetch/blob/4abbfd231f4bce7dbe65e060a6323fc6917fd6d9/src/index.js#L117-L120

I've filed a bug with them: node-fetch/node-fetch#1086

For now, the best we can do is attempt to fix the location header that comes back if it's a resolved URL and that URL points us to the same origin as our original proxy request. This allows valid URLs to come back from the proxy target and only strips the origin if it's a redirect to the same origin.

Scenarios Tested

I have a manual setup where a redirect is returned. I see now that the location header is what I expect:

before:

» curl -I http://localhost:5000/start
HTTP/1.1 302 Found
x-powered-by: Express
location: http://localhost:5001/somewhereelse

after:

» curl -I http://localhost:5000/start
HTTP/1.1 302 Found
x-powered-by: Express
location: /somewhereelse