Incorrect max-age and s-max-age usage in HttpCache feature

[Rafał Kuźmiński]

Ktor Version and Engine Used (client or server and name)
Ktor 1.3.2 JVM

Describe the bug
HttpCache feature is using s-max-age for Private and max-age for public cache, and I think it should be other way around.

Current code:

   val maxAgeKey = if (isPrivate) "s-max-age" else "max-age"

    val maxAge = cacheControl.firstOrNull { it.value.startsWith(maxAgeKey) }
        ?.value?.split("=")
        ?.get(1)?.toInt()

so for header : Cache-Control: max-age=3600, private
maxAge would be null

Expected behavior
maxAgeKey should be "max-age" for private and "s-max-age" for public

[Sergey Mashkov]

Well, s-max-age is usually for proxy servers so it's not clear why don't we simply ignore it in client's feature

[Rafał Kuźmiński]

Yes, public cache and "s-max-age" shouldn't be necessary, but I think that one may implement its own proxy with Ktor Client, and then it would be useful

[Sergey Mashkov]

Yes, but it definitely shouldn't work out of the box with default options. We need to correct it to avoid accidental caching (that in theory could even lead to vulnurabilities).