This revamps the way proxy handling is done to allow us to just proceed as
normal, and then if we get HTTP errors that indicate that we need a proxy or
need proxy credentials, we ask for them and then retry everything.
We still try to auto-detect the need for a proxy on our very first invocation
because on the first invocation, a failure to fetch a URL may well indicate
that a proxy is needed, but that same assumption does not hold on subsequent
invocations. In those later cases, it's probably just a transient network
failure and it would be weird and annoying to pop up the "please provide proxy
config" dialog in those cases.
Thanks pb00068 for getting this ball rolling, even though once again I have
nearly entirely rewritten the PR. I need to kick that habit. :)
Null tolerance is a plague. I wish `String` did not admit nulls and we had to
use Optional<String> for potentially null strings, but Java will forever be
cursed with the billion dollar mistake.
just in case if you wonder why i'm doing this: because i often want to see how particular issue was resolved or feature was implemented and PRs usually contain enough explanation 👀
We were already doing this for bootstrap.properties-based launches, but there's
no reason to restrict it to that. If you run Getdown with an appbase and an
appdir, it can create the app dir and download the app into it.
This enables scenarios where getdown is installed to a shared location and
users that run the app install it in their private storage area (or on a
machine local file system, or who knows).
Closes#163.
Michael Bayne