private void ConfigureRequest(HttpWebRequest request)
{
request.Proxy = _proxyCache.GetProxy(request.RequestUri);
if (request.Proxy != null && request.Proxy.Credentials == null)
{
request.Proxy.Credentials = CredentialCache.DefaultCredentials;
}
if (_previousResponse == null || ShouldKeepAliveBeUsedInRequest(_previousRequest, _previousResponse))
{
// Try to use the cached credentials (if any, for the first request)
request.Credentials = _credentialCache.GetCredentials(request.RequestUri);
// If there are no cached credentials, use the default ones
if (request.Credentials == null)
{
request.UseDefaultCredentials = true;
}
}
else if (_previousStatusCode == HttpStatusCode.ProxyAuthenticationRequired)
{
request.Proxy.Credentials = _credentialProvider.GetCredentials(
request, CredentialType.ProxyCredentials, retrying: _proxyCredentialsRetryCount > 0);
_continueIfFailed = request.Proxy.Credentials != null;
_proxyCredentialsRetryCount++;
}
else if (_previousStatusCode == HttpStatusCode.Unauthorized)
{
SetCredentialsOnAuthorizationError(request);
}
SetKeepAliveHeaders(request, _previousResponse);
if (_usingSTSAuth)
{
// Add request headers if the server requires STS based auth.
STSAuthHelper.PrepareSTSRequest(request);
}
// Wrap the credentials in a CredentialCache in case there is a redirect
// and credentials need to be kept around.
request.Credentials = request.Credentials.AsCredentialCache(request.RequestUri);
}
public HttpWebResponse GetResponse(CancellationToken token)
{
_previousRequest = null;
_previousResponse = null;
_previousStatusCode = null;
_usingSTSAuth = false;
_continueIfFailed = true;
_proxyCredentialsRetryCount = 0;
_credentialsRetryCount = 0;
int failureCount = 0;
const int MaxFailureCount = 10;
while (true)
{
// Create the request
var request = (HttpWebRequest)_createRequest();
MakeCancelable(request, token);
ConfigureRequest(request);
try
{
var auth = request.Headers["Authorization"];
_basicAuthIsUsedInPreviousRequest = (auth != null) &&
auth.StartsWith("Basic ", StringComparison.Ordinal);
// Prepare the request, we do something like write to the request stream
// which needs to happen last before the request goes out
_prepareRequest(request);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Cache the proxy and credentials
_proxyCache.Add(request.Proxy);
ICredentials credentials = request.Credentials;
_credentialCache.Add(request.RequestUri, credentials);
_credentialCache.Add(response.ResponseUri, credentials);
return(response);
}
catch (WebException ex)
{
++failureCount;
if (failureCount >= MaxFailureCount)
{
throw;
}
using (IHttpWebResponse response = GetResponse(ex.Response))
{
if (response == null &&
ex.Status != WebExceptionStatus.SecureChannelFailure)
{
// No response, something went wrong so just rethrow
throw;
}
// Special case https connections that might require authentication
if (ex.Status == WebExceptionStatus.SecureChannelFailure)
{
if (_continueIfFailed)
{
// Act like we got a 401 so that we prompt for credentials on the next request
_previousStatusCode = HttpStatusCode.Unauthorized;
continue;
}
throw;
}
// If we were trying to authenticate the proxy or the request and succeeded, cache the result.
if (_previousStatusCode == HttpStatusCode.ProxyAuthenticationRequired &&
response.StatusCode != HttpStatusCode.ProxyAuthenticationRequired)
{
_proxyCache.Add(request.Proxy);
}
else if (_previousStatusCode == HttpStatusCode.Unauthorized &&
response.StatusCode != HttpStatusCode.Unauthorized)
{
_credentialCache.Add(request.RequestUri, request.Credentials);
_credentialCache.Add(response.ResponseUri, request.Credentials);
}
_usingSTSAuth = STSAuthHelper.TryRetrieveSTSToken(request.RequestUri, response);
if (!IsAuthenticationResponse(response) || !_continueIfFailed)
{
throw;
}
_previousRequest = request;
_previousResponse = response;
_previousStatusCode = _previousResponse.StatusCode;
}
}
}
}
