public static bool TryCreate(out IWebProxy proxy)
{
// This will get basic proxy setting from system using existing
// WinInetProxyHelper functions. If no proxy is enabled, it will return null.
SafeWinHttpHandle sessionHandle = null;
proxy = null;
WinInetProxyHelper proxyHelper = new WinInetProxyHelper();
if (!proxyHelper.ManualSettingsOnly && !proxyHelper.AutoSettingsUsed)
{
return(false);
}
if (proxyHelper.AutoSettingsUsed)
{
sessionHandle = Interop.WinHttp.WinHttpOpen(
IntPtr.Zero,
Interop.WinHttp.WINHTTP_ACCESS_TYPE_NO_PROXY,
Interop.WinHttp.WINHTTP_NO_PROXY_NAME,
Interop.WinHttp.WINHTTP_NO_PROXY_BYPASS,
(int)Interop.WinHttp.WINHTTP_FLAG_ASYNC);
if (sessionHandle.IsInvalid)
{
// Proxy failures are currently ignored by managed handler.
return(false);
}
}
proxy = new HttpWindowsProxy(proxyHelper, sessionHandle);
return(true);
}
public void Dispose()
{
if (!_disposed)
{
_disposed = true;
if (_sessionHandle != null && !_sessionHandle.IsInvalid)
{
SafeWinHttpHandle.DisposeAndClearHandle(ref _sessionHandle);
}
}
}
private HttpWindowsProxy(WinInetProxyHelper proxyHelper, SafeWinHttpHandle sessionHandle)
{
_proxyHelper = proxyHelper;
_sessionHandle = sessionHandle;
if (proxyHelper.ManualSettingsUsed)
{
ParseProxyConfig(proxyHelper.Proxy, out _insecureProxyUri, out _secureProxyUri);
if (_insecureProxyUri == null && _secureProxyUri == null)
{
// If advanced parsing by protocol fails, fall-back to simplified parsing.
_insecureProxyUri = _secureProxyUri = GetUriFromString(proxyHelper.Proxy);
}
if (!string.IsNullOrWhiteSpace(proxyHelper.ProxyBypass))
{
int idx = 0;
int start = 0;
string tmp;
// Process bypass list for manual setting.
// Initial list size is best guess based on string length assuming each entry is at least 5 characters on average.
_bypass = new List <Regex>(proxyHelper.ProxyBypass.Length / 5);
while (idx < proxyHelper.ProxyBypass.Length)
{
// Strip leading spaces and scheme if any.
while (idx < proxyHelper.ProxyBypass.Length && proxyHelper.ProxyBypass[idx] == ' ')
{
idx += 1;
}
;
if (string.Compare(proxyHelper.ProxyBypass, idx, "http://", 0, 7, StringComparison.OrdinalIgnoreCase) == 0)
{
idx += 7;
}
else if (string.Compare(proxyHelper.ProxyBypass, idx, "https://", 0, 8, StringComparison.OrdinalIgnoreCase) == 0)
{
idx += 8;
}
if (idx < proxyHelper.ProxyBypass.Length && proxyHelper.ProxyBypass[idx] == '[')
{
// Strip [] from IPv6 so we can use IdnHost laster for matching.
idx += 1;
}
start = idx;
while (idx < proxyHelper.ProxyBypass.Length && proxyHelper.ProxyBypass[idx] != ' ' && proxyHelper.ProxyBypass[idx] != ';' && proxyHelper.ProxyBypass[idx] != ']')
{
idx += 1;
}
;
if (idx == start)
{
// Empty string.
tmp = null;
}
else if (string.Compare(proxyHelper.ProxyBypass, start, "<local>", 0, 7, StringComparison.OrdinalIgnoreCase) == 0)
{
_bypassLocal = true;
tmp = null;
}
else
{
tmp = proxyHelper.ProxyBypass.Substring(start, idx - start);
}
// Skip trailing characters if any.
if (idx < proxyHelper.ProxyBypass.Length && proxyHelper.ProxyBypass[idx] != ';')
{
// Got stopped at space or ']'. Strip until next ';' or end.
while (idx < proxyHelper.ProxyBypass.Length && proxyHelper.ProxyBypass[idx] != ';')
{
idx += 1;
}
;
}
if (idx < proxyHelper.ProxyBypass.Length && proxyHelper.ProxyBypass[idx] == ';')
{
idx++;
}
if (tmp == null)
{
continue;
}
try
{
// Escape any special characters and unescape * to get wildcard pattern match.
Regex re = new Regex(Regex.Escape(tmp).Replace("\\*", ".*?") + "$",
RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);
_bypass.Add(re);
}
catch (Exception ex)
{
}
}
if (_bypass.Count == 0)
{
// Bypass string only had garbage we did not parse.
_bypass = null;
}
}
if (_bypassLocal)
{
_localIp = new List <IPAddress>();
foreach (NetworkInterface netInterface in NetworkInterface.GetAllNetworkInterfaces())
{
IPInterfaceProperties ipProps = netInterface.GetIPProperties();
foreach (UnicastIPAddressInformation addr in ipProps.UnicastAddresses)
{
_localIp.Add(addr.Address);
}
}
}
}
}
public bool GetProxyForUrl(
SafeWinHttpHandle sessionHandle,
Uri uri,
out Interop.WinHttp.WINHTTP_PROXY_INFO proxyInfo)
{
proxyInfo.AccessType = Interop.WinHttp.WINHTTP_ACCESS_TYPE_NO_PROXY;
proxyInfo.Proxy = IntPtr.Zero;
proxyInfo.ProxyBypass = IntPtr.Zero;
if (!_useProxy)
{
return(false);
}
bool useProxy = false;
Interop.WinHttp.WINHTTP_AUTOPROXY_OPTIONS autoProxyOptions;
autoProxyOptions.AutoConfigUrl = AutoConfigUrl;
autoProxyOptions.AutoDetectFlags = AutoDetect ?
(Interop.WinHttp.WINHTTP_AUTO_DETECT_TYPE_DHCP | Interop.WinHttp.WINHTTP_AUTO_DETECT_TYPE_DNS_A) : 0;
autoProxyOptions.AutoLoginIfChallenged = false;
autoProxyOptions.Flags =
(AutoDetect ? Interop.WinHttp.WINHTTP_AUTOPROXY_AUTO_DETECT : 0) |
(!string.IsNullOrEmpty(AutoConfigUrl) ? Interop.WinHttp.WINHTTP_AUTOPROXY_CONFIG_URL : 0);
autoProxyOptions.Reserved1 = IntPtr.Zero;
autoProxyOptions.Reserved2 = 0;
// AutoProxy Cache.
// https://docs.microsoft.com/en-us/windows/desktop/WinHttp/autoproxy-cache
// If the out-of-process service is active when WinHttpGetProxyForUrl is called, the cached autoproxy
// URL and script are available to the whole computer. However, if the out-of-process service is used,
// and the fAutoLogonIfChallenged flag in the pAutoProxyOptions structure is true, then the autoproxy
// URL and script are not cached. Therefore, calling WinHttpGetProxyForUrl with the fAutoLogonIfChallenged
// member set to TRUE results in additional overhead operations that may affect performance.
// The following steps can be used to improve performance:
// 1. Call WinHttpGetProxyForUrl with the fAutoLogonIfChallenged parameter set to false. The autoproxy
// URL and script are cached for future calls to WinHttpGetProxyForUrl.
// 2. If Step 1 fails, with ERROR_WINHTTP_LOGIN_FAILURE, then call WinHttpGetProxyForUrl with the
// fAutoLogonIfChallenged member set to TRUE.
//
// We match behavior of WINHTTP_ACCESS_TYPE_AUTOMATIC_PROXY and ignore errors.
var repeat = false;
do
{
_autoDetectionFailed = false;
if (Interop.WinHttp.WinHttpGetProxyForUrl(
sessionHandle,
uri.AbsoluteUri,
ref autoProxyOptions,
out proxyInfo))
{
useProxy = true;
break;
}
else
{
var lastError = Marshal.GetLastWin32Error();
if (lastError == Interop.WinHttp.ERROR_WINHTTP_LOGIN_FAILURE)
{
if (repeat)
{
// We don't retry more than once.
break;
}
else
{
repeat = true;
autoProxyOptions.AutoLoginIfChallenged = true;
}
}
else
{
if (lastError == Interop.WinHttp.ERROR_WINHTTP_AUTODETECTION_FAILED)
{
_autoDetectionFailed = true;
_lastTimeAutoDetectionFailed = Environment.TickCount;
}
break;
}
}
} while (repeat);
// Fall back to manual settings if available.
if (!useProxy && !string.IsNullOrEmpty(Proxy))
{
proxyInfo.AccessType = Interop.WinHttp.WINHTTP_ACCESS_TYPE_NAMED_PROXY;
proxyInfo.Proxy = Marshal.StringToHGlobalUni(Proxy);
proxyInfo.ProxyBypass = string.IsNullOrEmpty(ProxyBypass) ?
IntPtr.Zero : Marshal.StringToHGlobalUni(ProxyBypass);
useProxy = true;
}
return(useProxy);
}
