Fix gRPC status details trailer handling

spring-cloud-gateway-server-webflux/src/main/java/org/springframework/cloud/gateway/filter/headers/GRPCResponseHeadersFilter.java

@@ -36,12 +36,15 @@ public class GRPCResponseHeadersFilter implements HttpHeadersFilter, Ordered {
 
 	private static final String GRPC_MESSAGE_HEADER = "grpc-message";
 
+	private static final String GRPC_STATUS_DETAILS_BIN_HEADER = "grpc-status-details-bin";
+
 	@Override
 	public HttpHeaders filter(HttpHeaders headers, ServerWebExchange exchange) {
 		ServerHttpResponse response = exchange.getResponse();
 		if (isGRPC(exchange)) {
 			String grpcStatus = getGrpcStatus(headers);
 			String grpcMessage = getGrpcMessage(headers);
+			String grpcStatusDetailsBin = getGrpcStatusDetailsBin(headers);
 			if (grpcStatus != null) {
 				while (response instanceof ServerHttpResponseDecorator) {
 					response = ((ServerHttpResponseDecorator) response).getDelegate();
@@ -51,6 +54,9 @@ public HttpHeaders filter(HttpHeaders headers, ServerWebExchange exchange) {
 						.trailerHeaders(h -> {
 							h.set(GRPC_STATUS_HEADER, grpcStatus);
 							h.set(GRPC_MESSAGE_HEADER, grpcMessage);
+							if (grpcStatusDetailsBin != null) {
+								h.set(GRPC_STATUS_DETAILS_BIN_HEADER, grpcStatusDetailsBin);
+							}
 						});
 				}
 			}
@@ -69,6 +75,11 @@ private boolean isGRPC(ServerWebExchange exchange) {
 		return StringUtils.hasText(grpcStatusValue) ? grpcStatusValue : null;
 	}
 
+	private @Nullable String getGrpcStatusDetailsBin(HttpHeaders headers) {
+		final String grpcStatusDetailsBinValue = headers.getFirst(GRPC_STATUS_DETAILS_BIN_HEADER);
+		return StringUtils.hasText(grpcStatusDetailsBinValue) ? grpcStatusDetailsBinValue : null;
+	}
+
 	private String getGrpcMessage(HttpHeaders headers) {
 		final String grpcStatusValue = headers.getFirst(GRPC_MESSAGE_HEADER);
 		return StringUtils.hasText(grpcStatusValue) ? grpcStatusValue : "";

spring-cloud-gateway-server-webflux/src/test/java/org/springframework/cloud/gateway/filter/headers/GRPCResponseHeadersFilterTests.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2013-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.gateway.filter.headers;
+
+import java.util.function.Consumer;
+
+import io.netty.handler.codec.http.DefaultHttpHeaders;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Mono;
+import reactor.netty.http.server.HttpServerResponse;
+
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.server.reactive.AbstractServerHttpResponse;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.web.server.ServerWebExchange;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author hutiefang
+ */
+public class GRPCResponseHeadersFilterTests {
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void shouldIncludeGrpcStatusDetailsBinTrailerIfGRPC() {
+		ServerHttpRequest request = MockServerHttpRequest.get("http://localhost:8080/get")
+			.header(HttpHeaders.CONTENT_TYPE, "application/grpc")
+			.build();
+		HttpServerResponse nativeResponse = mock(HttpServerResponse.class);
+		when(nativeResponse.trailerHeaders(any())).thenReturn(nativeResponse);
+		ServerWebExchange exchange = mock(ServerWebExchange.class);
+		when(exchange.getRequest()).thenReturn(request);
+		when(exchange.getResponse()).thenReturn(new TestServerHttpResponse(nativeResponse));
+
+		HttpHeaders headers = new HttpHeaders();
+		headers.set("grpc-status", "13");
+		headers.set("grpc-message", "internal");
+		headers.set("grpc-status-details-bin", "AQID");
+
+		new GRPCResponseHeadersFilter().filter(headers, exchange);
+
+		ArgumentCaptor<Consumer<io.netty.handler.codec.http.HttpHeaders>> captor = ArgumentCaptor
+			.forClass(Consumer.class);
+		verify(nativeResponse).trailerHeaders(captor.capture());
+		io.netty.handler.codec.http.HttpHeaders trailers = new DefaultHttpHeaders();
+		captor.getValue().accept(trailers);
+		assertThat(trailers.get("grpc-status")).isEqualTo("13");
+		assertThat(trailers.get("grpc-message")).isEqualTo("internal");
+		assertThat(trailers.get("grpc-status-details-bin")).isEqualTo("AQID");
+	}
+
+	private static final class TestServerHttpResponse extends AbstractServerHttpResponse {
+
+		private final HttpServerResponse nativeResponse;
+
+		private TestServerHttpResponse(HttpServerResponse nativeResponse) {
+			super(new DefaultDataBufferFactory());
+			this.nativeResponse = nativeResponse;
+		}
+
+		@Override
+		@SuppressWarnings("unchecked")
+		public <T> T getNativeResponse() {
+			return (T) this.nativeResponse;
+		}
+
+		@Override
+		protected Mono<Void> writeWithInternal(Publisher<? extends DataBuffer> body) {
+			return Mono.empty();
+		}
+
+		@Override
+		protected Mono<Void> writeAndFlushWithInternal(Publisher<? extends Publisher<? extends DataBuffer>> body) {
+			return Mono.empty();
+		}
+
+		@Override
+		protected void applyStatusCode() {
+		}
+
+		@Override
+		protected void applyHeaders() {
+		}
+
+		@Override
+		protected void applyCookies() {
+		}
+
+	}
+
+}