Detect network proxy - currectly for Windows only

Its designed for detecting the proxy once in a while, it doesn't cache internet sessions etc, so it could be relatively slow if you are querying it a lot.

I will be using these with NTLM proxies most of the time.

Compiles for C++, so I can use std::string objects, but could be converted to C.

HOW TO USE:

#include <detectproxy/detectproxy.hpp>
...
string proxy = detectproxy(target_url);

Now you can feed the "proxy" into libCurl, it will be something like proxy.host.com:8888

All strings are assumed UTF-8.

Note that to get libCurl to authenticate against NTLM proxies, you must also set user/pass to blank strings "".

Note that detectproxy() will THROW a runtime_error if there is some sort of error.

You can also do:

string proxy = detectproxy(target_url, &std::cout);

to see messages during the detection process.

TODO:

• Tests (will need some proxies to test against... how?)
• Improve the proxy list splitting (its very naive at the moment)
• Handle the proxy-bypass list
• Cache the internal internet session - threadsafe?
• Test situation where proxy server does not need or want user/pass.
• Handle WinHttpGetProxyForUrl potential crashes (I have seen mention that old McAfee can cause crashes).
• Test chinese URLs.