public override async ValueTask TransformRequestAsync(HttpContext httpContext, HttpRequestMessage proxyRequest, string destinationPrefix)
{
if (ShouldCopyRequestHeaders.GetValueOrDefault(true))
{
await base.TransformRequestAsync(httpContext, proxyRequest, destinationPrefix);
}
if (RequestTransforms.Count == 0)
{
return;
}
var transformContext = new RequestTransformContext()
{
DestinationPrefix = destinationPrefix,
HttpContext = httpContext,
ProxyRequest = proxyRequest,
Path = httpContext.Request.Path,
Query = new QueryTransformContext(httpContext.Request),
HeadersCopied = ShouldCopyRequestHeaders.GetValueOrDefault(true),
};
foreach (var requestTransform in RequestTransforms)
{
await requestTransform.ApplyAsync(transformContext);
}
// Allow a transform to directly set a custom RequestUri.
proxyRequest.RequestUri ??= RequestUtilities.MakeDestinationAddress(
transformContext.DestinationPrefix, transformContext.Path, transformContext.Query.QueryString);
}
private void CopyRequestHeaders(HttpContext context, HttpRequestMessage proxyRequest)
{
// Transforms that were run in the first pass.
HashSet <string> transformsRun = null;
if (ShouldCopyRequestHeaders.GetValueOrDefault(true))
{
foreach (var header in context.Request.Headers)
{
var headerName = header.Key;
var headerValue = header.Value;
if (StringValues.IsNullOrEmpty(headerValue))
{
continue;
}
// Filter out HTTP/2 pseudo headers like ":method" and ":path", those go into other fields.
if (headerName.Length > 0 && headerName[0] == ':')
{
continue;
}
if (RequestHeaderTransforms.TryGetValue(headerName, out var transform))
{
(transformsRun ??= new HashSet <string>(StringComparer.OrdinalIgnoreCase)).Add(headerName);
headerValue = transform.Apply(context, proxyRequest, headerValue);
if (StringValues.IsNullOrEmpty(headerValue))
{
continue;
}
}
RequestUtilities.AddHeader(proxyRequest, headerName, headerValue);
}
}
transformsRun ??= EmptyHash;
// Run any transforms that weren't run yet.
foreach (var(headerName, transform) in RequestHeaderTransforms)
{
if (!transformsRun.Contains(headerName))
{
var headerValue = transform.Apply(context, proxyRequest, StringValues.Empty);
if (!StringValues.IsNullOrEmpty(headerValue))
{
RequestUtilities.AddHeader(proxyRequest, headerName, headerValue);
}
}
}
}
