Hey, I’m using `EnvironmentKey.uri().of().required...

# http4k

[DanielZ]

Hey,
I’m using EnvironmentKey.uri().of().required() to use the Uri later in ClientFilters.SetHostFrom().
When I make the client call I run into the situation that I receive the error that schema is not a valid http(s) schema.
Is there an elegant way to ensure that the Uri contains a valid schema? One option which came into my mind was using map in the lens, which didn’t felt nicely.
Do you have some other ideas / advices?

[Andrew O'Hara]

If you're using values4k, you can make a custom value type that requires the scheme to be present.

class Url(value: Uri): AbstractValue<Uri>(value) {
    companion object: ValueFactory<Url, Uri>(
        coerceFn = ::Url,
        parseFn = Uri::of,
        validation = {it.scheme.isNotEmpty() }
    )
}

val key = EnvironmentKey.value(Url).required("my_url")

[DanielZ]

No, I’m not. Thank you for that idea. I can even without values4k create my own Uri class which is doing all the validation. In addition I have then to create my own lenses.

[Andrew O'Hara]

The benefit of values4k is that http4k has built-in support for it. But you can definitely make your own value class with a custom lens adapater.