private async Task HandleGrpcWebRequest(HttpContext httpContext, ServerGrpcWebContext grcpWebContext)
{
var feature = new GrpcWebFeature(grcpWebContext, httpContext);
var initialProtocol = httpContext.Request.Protocol;
// Modifying the request is required to stop Grpc.AspNetCore.Server from rejecting it
httpContext.Request.Protocol = GrpcWebProtocolConstants.Http2Protocol;
httpContext.Request.ContentType = ResolveContentType(GrpcWebProtocolConstants.GrpcContentType, httpContext.Request.ContentType !);
// Update response content type back to gRPC-Web
httpContext.Response.OnStarting(() =>
{
// Reset request protocol back to its original value. Not doing this causes a 2 second
// delay when making HTTP/1.1 calls.
httpContext.Request.Protocol = initialProtocol;
if (CommonGrpcProtocolHelpers.IsContentType(GrpcWebProtocolConstants.GrpcContentType, httpContext.Response.ContentType !))
{
var contentType = grcpWebContext.Response == ServerGrpcWebMode.GrpcWeb
? GrpcWebProtocolConstants.GrpcWebContentType
: GrpcWebProtocolConstants.GrpcWebTextContentType;
var responseContentType = ResolveContentType(contentType, httpContext.Response.ContentType);
httpContext.Response.ContentType = responseContentType;
Log.SendingGrpcWebResponse(_logger, responseContentType);
}
return(Task.CompletedTask);
});
try
{
await _next(httpContext);
// If trailers have already been written in CompleteAsync then this will no-op
await feature.WriteTrailersAsync();
}
finally
{
feature.DetachFromContext(httpContext);
}
}
public GrpcWebFeature(ServerGrpcWebContext grcpWebContext, HttpContext httpContext)
{
// Capture existing features. We'll use these internally, and restore them onto the context
// once the middleware has finished executing.
// Note that some of these will be missing depending on the host and protocol.
// e.g.
// - IHttpResponseTrailersFeature and IHttpResetFeature will be missing when HTTP/1.1.
// - IRequestBodyPipeFeature will be missing when in IIS.
_initialRequestFeature = httpContext.Features.Get <IRequestBodyPipeFeature>();
_initialResponseFeature = GetRequiredFeature <IHttpResponseBodyFeature>(httpContext);
_initialResetFeature = httpContext.Features.Get <IHttpResetFeature>();
_initialTrailersFeature = httpContext.Features.Get <IHttpResponseTrailersFeature>();
var innerReader = _initialRequestFeature?.Reader ?? httpContext.Request.BodyReader;
var innerWriter = _initialResponseFeature.Writer ?? httpContext.Response.BodyWriter;
Trailers = new HeaderDictionary();
if (grcpWebContext.Request == ServerGrpcWebMode.GrpcWebText)
{
Reader = new Base64PipeReader(innerReader);
}
else
{
Reader = innerReader;
}
if (grcpWebContext.Response == ServerGrpcWebMode.GrpcWebText)
{
Writer = new Base64PipeWriter(innerWriter);
}
else
{
Writer = innerWriter;
}
httpContext.Features.Set <IRequestBodyPipeFeature>(this);
httpContext.Features.Set <IHttpResponseBodyFeature>(this);
httpContext.Features.Set <IHttpResponseTrailersFeature>(this);
httpContext.Features.Set <IHttpResetFeature>(this);
}
