[5.5] Added domain helper to route

[m1guelpf]

Originally sent by @robinvdvleuten to 5.4 branch in #19243, submitting to 5.5 branch

[robinvdvleuten]

Nice! Thanks @m1guelpf!

[deleugpn]

@m1guelpf I opened a PR on your fork (https://github.com/m1guelpf/framework/pull/1) to add a specific test for this. The test passes on your master but would fail without the new feature.
I noticed that this PR corrects some of the tests that would be broken, but currently it doesn't really have a test for this specifically. I think if you merge the PR the commit should show up here automatically.

[m1guelpf]

@deleugpn Thank you! Merged

[deleugpn]

[ntzm]

I'd rather transitioning from 5.4 to 5.5 to be as simple as possible, but changing things like this will make it more difficult. I'm not saying I disagree with the feature, I'd just rather it not change the current behaviour to be honest.

[m1guelpf]

Maybe it would be better to keep current domain() functionality, but use the new functionality when passing a parameter, like:

domain()

would act as it does now, but

domain($domain)

would do new behaviour.
What do @taylorotwell & @themsaid think about this?

[deleugpn]

I think it would be quite weird to have a method that return either a string or a Route object.

[robinvdvleuten]

I tried to stay as close to the Laravel API as possible; if you would like to add a prefix you call prefix('/api') but if you want to get the prefix of the route you'll call getPrefix().

[decadence]

AFAIK now you can define domain only on route group. Does this PR bring opportunity to define domain for every single Route? Or I misunderstood something?

[deleugpn]

@decadence I would infer that it does since the test I wrote for this do exactly that.

[taylorotwell]

@m1guelpf yes you should make the existing domain method function as both a getter and setter depending on if an argument is passed. We do that in other parts of the framework occasionally.

[taylorotwell]

Eh, nevermind, I guess we have other get* methods on this class.

[joshmanders]

Excellent PR!