[Feature request] Add response.isOk to check if the response status code is 2xx

[petrpavlik]

I believe that the community would benefit from adding a simple boolean check whether the status code of the response is acceptable.

I took inspiration from the javascript's fetch API where the response exposes response.ok to check whether the status code is >= 200 and < 300 (see the documentation), and created a simple extension to make my life easier.

extension HTTPClientResponse {
    var isOk: Bool {
        status.code >= 200 && status.code < 300
    }
}

Happy to contribute (and write tests) this if there is interest from the side of the maintainers.

[Lukasa]

I don't have any particular objection to this extension, though I'm not sure how useful it actually is: 3xx responses aren't errors, and many 2xx responses are conceptually not equivalent to ok. But the weight of fetch matters a fair bit here.

[petrpavlik]

I think that it's just a convenience abstraction over whether a successful request returns 200, 201, or what. That's how I've been using it.

My response handling usually looks something like this

if response.isOk {
  // try to parse the expected JSON
} else {
 // get the status code and try to parse the expected error JSON for 400 errors
}

This is for cases where I do not expect that a request may respond with a 3xx redirect.