Swagger-ui redirect fails when on IPv6 locally

[virkt25]

Description / Steps to reproduce / Feature proposal

Create an app using lb4 app. Have your OS configured for IPv6 (default on Macs). Go to http://[::1]:3000/swagger-ui

Instead of loading the swagger-ui modules to explore the API's an error is generated saying Failed to load API Definition.

I suspect this has something to do with the RegEx used below. I played around with the RegEx used in regex101.com and I think the correct regex should be /:[0-9]+(?!])/ to work with IPv6 addresses.

I made the changes but can't verify locally but for some reason I can't verify the fix ... creating this issue to track it as I plan to go back to trying to debug my dev environment. I can't even get a console.log statement added to the function to print :/

https://github.com/strongloop/loopback-next/blob/master/packages/rest/src/rest.server.ts#L358-L371

Acceptance Criteria

• Able to redirect to /swagger-ui when on IPv6 without an error

[dhmlau]

@virkt25 , trying to understand the impact of not getting it fixed by GA, though i think we should.
IIRC, http://[::1]:3000/swagger-ui gives the error message in the original description. Can we change the message to ask users opening another URL http://localhost:3000/swagger-ui instead? or it won't work in all cases too? Thanks.

[virkt25]

localhost works fine, the issue with IPv6 is the RegEx is looking for :# to match a port but in this case it matches :1 instead of :3000.

I wouldn't consider asking the users to open http:localhost:3000/swagger-ui an acceptable fix since the app startup says the app has started on http://[::1]:3000 and the redirect should work there.

It's a quick fix ... I just need to fix my setup / bootstrap / something otherwise the suggested fix is there and tested on a few different strings on regex101.com

[dhmlau]

PR #1637

[dhmlau]

@raymondfeng , I just assigned it to you since PR #1637 is yours.

[raymondfeng]

Fixed by #1637