private static void SetRequestHeaders(HttpWebRequest webRequest, HttpRequestMessage request)
{
WebHeaderCollection webRequestHeaders = webRequest.Headers;
HttpRequestHeaders headers = request.Headers;
// Most headers are just added directly to HWR's internal headers collection. But there are some exceptions
// requiring different handling.
// The following bool vars are used to skip string comparison when not required: E.g. if the 'Host' header
// was not set, we don't need to compare every header in the collection with 'Host' to make sure we don't
// add it to HWR's header collection.
bool isHostSet = headers.Contains(HttpKnownHeaderNames.Host);
bool isExpectSet = headers.Contains(HttpKnownHeaderNames.Expect);
bool isTransferEncodingSet = headers.Contains(HttpKnownHeaderNames.TransferEncoding);
bool isConnectionSet = headers.Contains(HttpKnownHeaderNames.Connection);
if (isHostSet)
{
string host = headers.Host;
if (host != null)
{
webRequest.Host = host;
}
}
// The following headers (Expect, Transfer-Encoding, Connection) have both a collection property and a
// bool property indicating a special value. Internally (in HttpHeaders) we don't distinguish between
// "special" values and other values. So we must make sure that we add all but the special value to HWR.
// E.g. the 'Transfer-Encoding: chunked' value must be set using HWR.SendChunked, whereas all other values
// can be added to the 'Transfer-Encoding'.
if (isExpectSet)
{
string expectHeader = headers.Expect.GetHeaderStringWithoutSpecial();
// Was at least one non-special value set?
if (!String.IsNullOrEmpty(expectHeader) || !headers.Expect.IsSpecialValueSet)
{
webRequestHeaders.AddInternal(HttpKnownHeaderNames.Expect, expectHeader);
}
}
if (isTransferEncodingSet)
{
string transferEncodingHeader = headers.TransferEncoding.GetHeaderStringWithoutSpecial();
// Was at least one non-special value set?
if (!String.IsNullOrEmpty(transferEncodingHeader) || !headers.TransferEncoding.IsSpecialValueSet)
{
webRequestHeaders.AddInternal(HttpKnownHeaderNames.TransferEncoding, transferEncodingHeader);
}
}
if (isConnectionSet)
{
string connectionHeader = headers.Connection.GetHeaderStringWithoutSpecial();
// Was at least one non-special value set?
if (!String.IsNullOrEmpty(connectionHeader) || !headers.Connection.IsSpecialValueSet)
{
webRequestHeaders.AddInternal(HttpKnownHeaderNames.Connection, connectionHeader);
}
}
foreach (var header in request.Headers.GetHeaderStrings())
{
string headerName = header.Key;
if ((isHostSet && AreEqual(HttpKnownHeaderNames.Host, headerName)) ||
(isExpectSet && AreEqual(HttpKnownHeaderNames.Expect, headerName)) ||
(isTransferEncodingSet && AreEqual(HttpKnownHeaderNames.TransferEncoding, headerName)) ||
(isConnectionSet && AreEqual(HttpKnownHeaderNames.Connection, headerName)))
{
continue; // Header was already added.
}
// Use AddInternal() to skip validation.
webRequestHeaders.AddInternal(header.Key, header.Value);
}
}
