public Task <HttpResponseMessage> SendAsync(HttpRequestMessage request, bool doRequestAuth, CancellationToken cancellationToken)
{
if (_proxy == null)
{
return(SendAsyncCore(request, null, doRequestAuth, isProxyConnect: false, cancellationToken));
}
// Do proxy lookup.
Uri?proxyUri = null;
try
{
Debug.Assert(request.RequestUri != null);
if (!_proxy.IsBypassed(request.RequestUri))
{
if (_proxy is IMultiWebProxy multiWebProxy)
{
MultiProxy multiProxy = multiWebProxy.GetMultiProxy(request.RequestUri);
if (multiProxy.ReadNext(out proxyUri, out bool isFinalProxy) && !isFinalProxy)
{
return(SendAsyncMultiProxy(request, doRequestAuth, multiProxy, proxyUri, cancellationToken));
}
}
else
{
proxyUri = _proxy.GetProxy(request.RequestUri);
}
}
}
catch (Exception ex)
{
// Eat any exception from the IWebProxy and just treat it as no proxy.
// This matches the behavior of other handlers.
if (NetEventSource.IsEnabled)
{
NetEventSource.Error(this, $"Exception from {_proxy.GetType().Name}.GetProxy({request.RequestUri}): {ex}");
}
}
if (proxyUri != null && proxyUri.Scheme != UriScheme.Http)
{
throw new NotSupportedException(SR.net_http_invalid_proxy_scheme);
}
return(SendAsyncCore(request, proxyUri, doRequestAuth, isProxyConnect: false, cancellationToken));
}
private HttpWindowsProxy(WinInetProxyHelper proxyHelper, SafeWinHttpHandle?sessionHandle)
{
_proxyHelper = proxyHelper;
_sessionHandle = sessionHandle;
if (proxyHelper.ManualSettingsUsed)
{
if (NetEventSource.Log.IsEnabled())
{
NetEventSource.Info(proxyHelper, $"ManualSettingsUsed, {proxyHelper.Proxy}");
}
_secureProxy = MultiProxy.Parse(_failedProxies, proxyHelper.Proxy, true);
_insecureProxy = MultiProxy.Parse(_failedProxies, proxyHelper.Proxy, false);
if (!string.IsNullOrWhiteSpace(proxyHelper.ProxyBypass))
{
int idx = 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 <string>(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;
}
int 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;
}
_bypass.Add(tmp);
}
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);
}
}
}
}
}
/// <summary>
/// Gets the proxy URIs.
/// </summary>
public MultiProxy GetMultiProxy(Uri uri)
{
// We need WinHTTP to detect and/or process a PAC (JavaScript) file. This maps to
// "Automatically detect settings" and/or "Use automatic configuration script" from IE
// settings. But, calling into WinHTTP can be slow especially when it has to call into
// the out-of-process service to discover, load, and run the PAC file. So, we skip
// calling into WinHTTP if there was a recent failure to detect a PAC file on the network.
// This is a common error. The default IE settings on a Windows machine consist of the
// single checkbox for "Automatically detect settings" turned on and most networks
// won't actually discover a PAC file on the network since WPAD protocol isn't configured.
if (_proxyHelper.AutoSettingsUsed && !_proxyHelper.RecentAutoDetectionFailure)
{
Interop.WinHttp.WINHTTP_PROXY_INFO proxyInfo = default;
try
{
if (_proxyHelper.GetProxyForUrl(_sessionHandle, uri, out proxyInfo))
{
// If WinHTTP just specified a Proxy with no ProxyBypass list, then
// we can return the Proxy uri directly.
if (proxyInfo.ProxyBypass == IntPtr.Zero)
{
if (proxyInfo.Proxy != IntPtr.Zero)
{
string proxyStr = Marshal.PtrToStringUni(proxyInfo.Proxy) !;
return(MultiProxy.CreateLazy(_failedProxies, proxyStr, IsSecureUri(uri)));
}
else
{
return(MultiProxy.Empty);
}
}
// A bypass list was also specified. This means that WinHTTP has fallen back to
// using the manual IE settings specified and there is a ProxyBypass list also.
// Since we're not really using the full WinHTTP stack, we need to use HttpSystemProxy
// to do the computation of the final proxy uri merging the information from the Proxy
// and ProxyBypass strings.
}
else
{
return(MultiProxy.Empty);
}
}
finally
{
Marshal.FreeHGlobal(proxyInfo.Proxy);
Marshal.FreeHGlobal(proxyInfo.ProxyBypass);
}
}
// Fallback to manual settings if present.
if (_proxyHelper.ManualSettingsUsed)
{
if (_bypassLocal)
{
IPAddress?address;
if (uri.IsLoopback)
{
// This is optimization for loopback addresses.
// Unfortunately this does not work for all local addresses.
return(MultiProxy.Empty);
}
// Pre-Check if host may be IP address to avoid parsing.
if (uri.HostNameType == UriHostNameType.IPv6 || uri.HostNameType == UriHostNameType.IPv4)
{
// RFC1123 allows labels to start with number.
// Leading number may or may not be IP address.
// IPv6 [::1] notation. '[' is not valid character in names.
if (IPAddress.TryParse(uri.IdnHost, out address))
{
// Host is valid IP address.
// Check if it belongs to local system.
foreach (IPAddress a in _localIp !)
{
if (a.Equals(address))
{
return(MultiProxy.Empty);
}
}
}
}
if (uri.HostNameType != UriHostNameType.IPv6 && !uri.IdnHost.Contains('.'))
{
// Not address and does not have a dot.
// Hosts without FQDN are considered local.
return(MultiProxy.Empty);
}
}
// Check if we have other rules for bypass.
if (_bypass != null)
{
foreach (string entry in _bypass)
{
// IdnHost does not have [].
if (SimpleRegex.IsMatchWithStarWildcard(uri.IdnHost, entry))
{
return(MultiProxy.Empty);
}
}
}
// We did not find match on bypass list.
return(IsSecureUri(uri) ? _secureProxy : _insecureProxy);
}
return(MultiProxy.Empty);
}
/// <summary>
/// Iterates a request over a set of proxies until one works, or all proxies have failed.
/// </summary>
/// <param name="multiProxy">The set of proxies to use.</param>
/// <param name="firstProxy">The first proxy try.</param>
private async Task <HttpResponseMessage> SendAsyncMultiProxy(HttpRequestMessage request, bool doRequestAuth, MultiProxy multiProxy, Uri firstProxy, CancellationToken cancellationToken)
{
HttpRequestException rethrowException = null;
do
{
try
{
return(await SendAsyncCore(request, firstProxy, doRequestAuth, isProxyConnect : false, cancellationToken).ConfigureAwait(false));
}
catch (HttpRequestException ex) when(ex.AllowRetry != RequestRetryType.NoRetry)
{
rethrowException = ex;
}
}while (multiProxy.ReadNext(out firstProxy, out _));
ExceptionDispatchInfo.Throw(rethrowException);
return(null); // should never be reached: VS doesn't realize Throw() never returns.
}