private static StructuredTransformer CreateTransformer(TransformBuilderContext context)
{
// RequestHeaderOriginalHostKey defaults to false, and CopyRequestHeaders defaults to true.
// If RequestHeaderOriginalHostKey was not specified then we need to make sure the transform gets
// added anyways to remove the original host. If CopyRequestHeaders is false then we can omit the
// transform.
if (context.CopyRequestHeaders.GetValueOrDefault(true) &&
!context.RequestTransforms.Any(item => item is RequestHeaderOriginalHostTransform))
{
context.AddOriginalHost(false);
}
// Add default forwarders only if they haven't already been added or disabled.
if (context.UseDefaultForwarders.GetValueOrDefault(true))
{
context.AddXForwarded();
}
return(new StructuredTransformer(
context.CopyRequestHeaders,
context.CopyResponseHeaders,
context.CopyResponseTrailers,
context.RequestTransforms,
context.ResponseTransforms,
context.ResponseTrailersTransforms));
}
public bool Build(TransformBuilderContext context, IReadOnlyDictionary <string, string> transformValues)
{
if (transformValues.TryGetValue(XForwardedKey, out var xforwardedHeaders))
{
var expected = 1;
var append = true;
if (transformValues.TryGetValue(AppendKey, out var appendValue))
{
expected++;
append = bool.Parse(appendValue);
}
var prefix = "X-Forwarded-";
if (transformValues.TryGetValue(PrefixForwardedKey, out var prefixValue))
{
expected++;
prefix = prefixValue;
}
TransformHelpers.CheckTooManyParameters(transformValues, expected);
// for, host, proto, Prefix
var tokens = xforwardedHeaders.Split(new[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
bool useFor, useHost, useProto, usePrefix;
useFor = useHost = useProto = usePrefix = false;
foreach (var token in tokens)
{
if (string.Equals(token, ForKey, StringComparison.OrdinalIgnoreCase))
{
useFor = true;
}
else if (string.Equals(token, HostKey, StringComparison.OrdinalIgnoreCase))
{
useHost = true;
}
else if (string.Equals(token, ProtoKey, StringComparison.OrdinalIgnoreCase))
{
useProto = true;
}
else if (string.Equals(token, PrefixKey, StringComparison.OrdinalIgnoreCase))
{
usePrefix = true;
}
else
{
throw new ArgumentException($"Unexpected value for X-Forwarded: {token}. Expected 'for', 'host', 'proto', or 'Prefix'");
}
}
context.AddXForwarded(prefix, useFor, useHost, useProto, usePrefix, append);
}
else if (transformValues.TryGetValue(ForwardedKey, out var forwardedHeader))
{
var useHost = false;
var useProto = false;
var useFor = false;
var useBy = false;
var forFormat = NodeFormat.None;
var byFormat = NodeFormat.None;
// for, host, proto, Prefix
var tokens = forwardedHeader.Split(new[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
foreach (var token in tokens)
{
if (string.Equals(token, ForKey, StringComparison.OrdinalIgnoreCase))
{
useFor = true;
forFormat = NodeFormat.Random; // RFC Default
}
else if (string.Equals(token, ByKey, StringComparison.OrdinalIgnoreCase))
{
useBy = true;
byFormat = NodeFormat.Random; // RFC Default
}
else if (string.Equals(token, HostKey, StringComparison.OrdinalIgnoreCase))
{
useHost = true;
}
else if (string.Equals(token, ProtoKey, StringComparison.OrdinalIgnoreCase))
{
useProto = true;
}
else
{
throw new ArgumentException($"Unexpected value for X-Forwarded: {token}. Expected 'for', 'host', 'proto', or 'by'");
}
}
var expected = 1;
var append = true;
if (transformValues.TryGetValue(AppendKey, out var appendValue))
{
expected++;
append = bool.Parse(appendValue);
}
if (useFor && transformValues.TryGetValue(ForFormatKey, out var forFormatString))
{
expected++;
forFormat = Enum.Parse <NodeFormat>(forFormatString, ignoreCase: true);
}
if (useBy && transformValues.TryGetValue(ByFormatKey, out var byFormatString))
{
expected++;
byFormat = Enum.Parse <NodeFormat>(byFormatString, ignoreCase: true);
}
TransformHelpers.CheckTooManyParameters(transformValues, expected);
context.UseDefaultForwarders = false;
if (useBy || useFor || useHost || useProto)
{
// Not using the extension to avoid resolving the random factory each time.
context.RequestTransforms.Add(new RequestHeaderForwardedTransform(_randomFactory, forFormat, byFormat, useHost, useProto, append));
}
}
else if (transformValues.TryGetValue(ClientCertKey, out var clientCertHeader))
{
TransformHelpers.CheckTooManyParameters(transformValues, expected: 1);
context.AddClientCertHeader(clientCertHeader);
}
else
{
return(false);
}
return(true);
}
// This is separate from Build for testing purposes.
internal StructuredTransformer BuildInternal(ProxyRoute route, Cluster cluster)
{
var rawTransforms = route.Transforms;
var context = new TransformBuilderContext
{
Services = _services,
Route = route,
Cluster = cluster,
};
if (rawTransforms?.Count > 0)
{
foreach (var rawTransform in rawTransforms)
{
var handled = false;
foreach (var factory in _factories)
{
if (factory.Build(context, rawTransform))
{
handled = true;
break;
}
}
if (!handled)
{
throw new ArgumentException($"Unknown transform: {string.Join(';', rawTransform.Keys)}");
}
}
}
// Let the app add any more transforms it wants.
foreach (var transformProvider in _providers)
{
transformProvider.Apply(context);
}
// Suppress the host by default
if (context.CopyRequestHeaders.GetValueOrDefault(true) && !context.UseOriginalHost.GetValueOrDefault())
{
// Headers were automatically copied, remove the Host header afterwards.
context.RequestTransforms.Add(new RequestHeaderValueTransform(HeaderNames.Host, string.Empty, append: false));
}
else if (!context.CopyRequestHeaders.GetValueOrDefault(true) && context.UseOriginalHost.GetValueOrDefault())
{
// Headers were not copied, copy the Host manually.
context.RequestTransforms.Add(RequestCopyHostTransform.Instance);
}
// Add default forwarders only if they haven't already been added or disabled.
if (context.UseDefaultForwarders.GetValueOrDefault(true))
{
context.AddXForwarded();
}
return(new StructuredTransformer(
context.CopyRequestHeaders,
context.CopyResponseHeaders,
context.CopyResponseTrailers,
context.RequestTransforms,
context.ResponseTransforms,
context.ResponseTrailersTransforms));
}
// This is separate from Build for testing purposes.
internal StructuredTransformer BuildInternal(ProxyRoute route, Cluster cluster)
{
var rawTransforms = route.Transforms;
var context = new TransformBuilderContext
{
Services = _services,
Route = route,
Cluster = cluster,
};
if (rawTransforms?.Count > 0)
{
foreach (var rawTransform in rawTransforms)
{
var handled = false;
foreach (var factory in _factories)
{
if (factory.Build(context, rawTransform))
{
handled = true;
break;
}
}
if (!handled)
{
throw new ArgumentException($"Unknown transform: {string.Join(';', rawTransform.Keys)}");
}
}
}
// Let the app add any more transforms it wants.
foreach (var transformProvider in _providers)
{
transformProvider.Apply(context);
}
// RequestHeaderOriginalHostKey defaults to false, and CopyRequestHeaders defaults to true.
// If RequestHeaderOriginalHostKey was not specified then we need to make sure the transform gets
// added anyways to remove the original host. If CopyRequestHeaders is false then we can omit the
// transform.
if (context.CopyRequestHeaders.GetValueOrDefault(true) &&
!context.RequestTransforms.Any(item => item is RequestHeaderOriginalHostTransform))
{
context.AddOriginalHost(false);
}
// Add default forwarders only if they haven't already been added or disabled.
if (context.UseDefaultForwarders.GetValueOrDefault(true))
{
context.AddXForwarded();
}
return(new StructuredTransformer(
context.CopyRequestHeaders,
context.CopyResponseHeaders,
context.CopyResponseTrailers,
context.RequestTransforms,
context.ResponseTransforms,
context.ResponseTrailersTransforms));
}