Package org.mockserver.netty.http3

Class Http3GrpcResponseWriter

java.lang.Object

org.mockserver.responsewriter.ResponseWriter

org.mockserver.netty.http3.Http3GrpcResponseWriter

All Implemented Interfaces:

GrpcStreamResponseWriter

public class Http3GrpcResponseWriter
extends ResponseWriter
implements GrpcStreamResponseWriter

A ResponseWriter that writes gRPC responses over HTTP/3 with correct gRPC wire framing: initial HEADERS (:status=200, content-type=application/grpc), DATA (gRPC length-prefixed message), and trailing HEADERS (grpc-status, grpc-message).

This follows the gRPC-over-HTTP/3 convention (same as HTTP/2): the grpc-status is conveyed in a trailing HEADERS frame at end-of-stream, which gRPC clients require. The initial HEADERS frame does NOT contain grpc-status.

For error responses without a body, the "trailers-only" pattern is used: a single HEADERS frame containing both :status=200 and grpc-status (no DATA frame).

The gRPC service and method names are captured from the original request (where GrpcHttp3Adapter places them as x-grpc-service and x-grpc-method headers) rather than from the response, because the matching pipeline does not propagate these internal headers to the matched response.

Field Summary

Fields inherited from class org.mockserver.responsewriter.ResponseWriter

configuration, mockServerLogger

Constructor Summary

Constructors

Constructor	Description
Http3GrpcResponseWriter(Configuration configuration, MockServerLogger mockServerLogger, io.netty.channel.ChannelHandlerContext ctx, GrpcProtoDescriptorStore descriptorStore, String grpcService, String grpcMethod)
Http3GrpcResponseWriter(Configuration configuration, MockServerLogger mockServerLogger, io.netty.channel.ChannelHandlerContext ctx, GrpcProtoDescriptorStore descriptorStore, String grpcService, String grpcMethod, WebSocketClientRegistry webSocketClientRegistry)

Method Summary

Modifier and Type	Method	Description
void	sendResponse(HttpRequest request, HttpResponse response)
void	writeGrpcStreamResponse(GrpcStreamResponse grpcStreamResponse, HttpRequest request)	Write a server-streaming gRPC response over HTTP/3: an initial HEADERS frame (:status=200, content-type=application/grpc, plus any configured headers), one DATA frame per message honouring per-message Delay, then a trailing HEADERS frame carrying grpc-status / grpc-message, followed by a QUIC stream output shutdown (or connection close when configured).

Methods inherited from class org.mockserver.responsewriter.ResponseWriter

addConnectionHeader, writeResponse, writeResponse, writeResponse

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Http3GrpcResponseWriter

public Http3GrpcResponseWriter(Configuration configuration,
 MockServerLogger mockServerLogger,
 io.netty.channel.ChannelHandlerContext ctx,
 GrpcProtoDescriptorStore descriptorStore,
 String grpcService,
 String grpcMethod)

Http3GrpcResponseWriter

public Http3GrpcResponseWriter(Configuration configuration,
 MockServerLogger mockServerLogger,
 io.netty.channel.ChannelHandlerContext ctx,
 GrpcProtoDescriptorStore descriptorStore,
 String grpcService,
 String grpcMethod,
 WebSocketClientRegistry webSocketClientRegistry)

Method Details

sendResponse

public void sendResponse(HttpRequest request,
 HttpResponse response)

Specified by:

sendResponse in class ResponseWriter

writeGrpcStreamResponse

public void writeGrpcStreamResponse(GrpcStreamResponse grpcStreamResponse,
 HttpRequest request)

Write a server-streaming gRPC response over HTTP/3: an initial HEADERS frame (:status=200, content-type=application/grpc, plus any configured headers), one DATA frame per message honouring per-message Delay, then a trailing HEADERS frame carrying grpc-status / grpc-message, followed by a QUIC stream output shutdown (or connection close when configured).

Mirrors the HTTP/2 GrpcStreamResponseActionHandler scheduling pattern, reusing GrpcStreamMessageEncoder for byte-identical framing. Delays are scheduled on the QUIC stream's own event-loop executor so writes stay ordered.

When a RESPONSE_STREAM breakpoint matcher matches, each outbound DATA frame is parked in the StreamFrameBreakpointRegistry (with stream-id suffix -h3-grpc-stream) before writing. Frame bytes are already byte[] from GrpcStreamMessageEncoder.encode(java.lang.String, com.google.protobuf.Descriptors.MethodDescriptor, org.mockserver.grpc.GrpcJsonMessageConverter) -- no ByteBuf is retained across the hold period. The decision future callback runs on the QUIC stream's event loop via ctx.channel().eventLoop().execute(), preserving frame ordering and respecting HTTP/3/QUIC flow control (Netty's outbound write path handles QUIC flow-control windows transparently). On stream close or error, all held frames are evicted.

Specified by:

writeGrpcStreamResponse in interface GrpcStreamResponseWriter

Parameters:

grpcStreamResponse - the matched server-streaming action

request - the originating request (for logging / descriptor lookup)