#460: find the http proxy on windows more reliably ---------------------------------+------------------------------------------ Reporter: duncan | Owner: Type: defect | Status: new Priority: normal | Milestone: Component: cabal-install tool | Version: 1.2.3.0 Severity: normal | Resolution: Keywords: | Difficulty: hard (< 1 day) Ghcversion: 6.8.3 | Platform: ---------------------------------+------------------------------------------ Comment (by duncan): It seems that the Web Proxy Auto-Discovery (WPAD) protocol is more than a bit dodgy. The right thing to do seems to be to check either the default settings with !WinHttpGetDefaultProxyConfiguration() though this is apparently more appropriate for system service. Alternatively we check the IE settings with WinHttpGetIEProxyConfigForCurrentUser(). It may specify a number of possibilities: * direct connection (no proxy) * specific proxy (and proxy bypass list) * auto config url (url of a .pac file) * auto detect (WPAD / !AutoProxy) In the third case we can use !WinHttpGetProxyForUrl() to get the .pac file, cache it and interpret it for us each time we look up a url. We can use the !WinHttpGetProxyForUrl() function in such a way that it never tries the WPAD / !AutoProxy protocol. In the last case we either bite the bullet and try this nasty insecure protocol or we fail, or perhaps we just try a direct connection anyway and then fail. The fact that the .pac file can specify a different proxy for each URL is a bit irksome. It means we'd have to keep a WinHTTP `HINTERNET` session about for the whole time we're making a sequence of HTTP requests. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/460#comment:1 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects