WebClient tests for socket and response format issues

Added test case for malformed response chunk, which is
now failing as expected.

See gh-27262

spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java

@@ -18,11 +18,15 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.io.UncheckedIOException;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
+import java.net.ServerSocket;
+import java.net.Socket;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
@@ -31,16 +35,21 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
 import okhttp3.mockwebserver.RecordedRequest;
+import okhttp3.mockwebserver.SocketPolicy;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.springframework.util.SocketUtils;
+import org.springframework.web.reactive.function.client.WebClient.ResponseSpec;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.netty.http.client.HttpClient;
@@ -83,7 +92,7 @@ class WebClientIntegrationTests {
 
 	@Retention(RetentionPolicy.RUNTIME)
 	@Target(ElementType.METHOD)
-	@ParameterizedTest(name = "[{index}] webClient [{0}]")
+	@ParameterizedTest(name = "[{index}] {displayName} [{0}]")
 	@MethodSource("arguments")
 	@interface ParameterizedWebClientTest {
 	}
@@ -113,7 +122,9 @@ private void startServer(ClientHttpConnector connector) {
 
 	@AfterEach
 	void shutdown() throws IOException {
-		this.server.shutdown();
+		if (server != null) {
+			this.server.shutdown();
+		}
 	}
 
 
@@ -1209,6 +1220,135 @@ void invalidDomain(ClientHttpConnector connector) {
 				.verify();
 	}
 
+	static Stream<Arguments> socketFaultArguments() {
+		Stream.Builder<Arguments> argumentsBuilder = Stream.builder();
+		arguments().forEach(arg -> {
+			argumentsBuilder.accept(Arguments.of(arg, SocketPolicy.DISCONNECT_AT_START));
+			argumentsBuilder.accept(Arguments.of(arg, SocketPolicy.DISCONNECT_DURING_REQUEST_BODY));
+			argumentsBuilder.accept(Arguments.of(arg, SocketPolicy.DISCONNECT_AFTER_REQUEST));
+		});
+		return argumentsBuilder.build();
+	}
+
+	@ParameterizedTest(name = "[{index}] {displayName} [{0}, {1}]")
+	@MethodSource("socketFaultArguments")
+	void prematureClosureFault(ClientHttpConnector connector, SocketPolicy socketPolicy) {
+		startServer(connector);
+
+		prepareResponse(response -> response
+				.setSocketPolicy(socketPolicy)
+				.setStatus("HTTP/1.1 200 OK")
+				.setHeader("Response-Header-1", "value 1")
+				.setHeader("Response-Header-2", "value 2")
+				.setBody("{\"message\": \"Hello, World!\"}"));
+
+		String uri = "/test";
+		Mono<String> result = this.webClient
+				.post()
+				.uri(uri)
+				// Random non-empty body to allow us to interrupt.
+				.bodyValue("{\"action\": \"Say hello!\"}")
+				.retrieve()
+				.bodyToMono(String.class);
+
+		StepVerifier.create(result)
+				.expectErrorSatisfies(throwable -> {
+					assertThat(throwable).isInstanceOf(WebClientRequestException.class);
+					WebClientRequestException ex = (WebClientRequestException) throwable;
+					// Varies between connector providers.
+					assertThat(ex.getCause()).isInstanceOf(IOException.class);
+				})
+				.verify();
+	}
+
+	static Stream<Arguments> malformedResponseChunkArguments() {
+		return Stream.of(
+				Arguments.of(new ReactorClientHttpConnector(), true),
+				Arguments.of(new JettyClientHttpConnector(), true),
+				// Apache injects the Transfer-Encoding header for us, and complains with an exception if we also
+				// add it. The other two connectors do not add the header at all. We need this header for the test
+				// case to work correctly.
+				Arguments.of(new HttpComponentsClientHttpConnector(), false)
+		);
+	}
+
+	@ParameterizedTest(name = "[{index}] {displayName} [{0}, {1}]")
+	@MethodSource("malformedResponseChunkArguments")
+	void malformedResponseChunksOnBodilessEntity(ClientHttpConnector connector, boolean addTransferEncodingHeader) {
+		Mono<?> result = doMalformedResponseChunks(connector, addTransferEncodingHeader, ResponseSpec::toBodilessEntity);
+
+		StepVerifier.create(result)
+				.expectErrorSatisfies(throwable -> {
+					assertThat(throwable).isInstanceOf(WebClientException.class);
+					WebClientException ex = (WebClientException) throwable;
+					assertThat(ex.getCause()).isInstanceOf(IOException.class);
+				})
+				.verify();
+	}
+
+	@ParameterizedTest(name = "[{index}] {displayName} [{0}, {1}]")
+	@MethodSource("malformedResponseChunkArguments")
+	void malformedResponseChunksOnEntityWithBody(ClientHttpConnector connector, boolean addTransferEncodingHeader) {
+		Mono<?> result = doMalformedResponseChunks(connector, addTransferEncodingHeader, spec -> spec.toEntity(String.class));
+
+		StepVerifier.create(result)
+				.expectErrorSatisfies(throwable -> {
+					assertThat(throwable).isInstanceOf(WebClientException.class);
+					WebClientException ex = (WebClientException) throwable;
+					assertThat(ex.getCause()).isInstanceOf(IOException.class);
+				})
+				.verify();
+	}
+
+	private <T> Mono<T> doMalformedResponseChunks(
+			ClientHttpConnector connector,
+			boolean addTransferEncodingHeader,
+			Function<ResponseSpec, Mono<T>> responseHandler
+	) {
+		int port = SocketUtils.findAvailableTcpPort();
+
+		Thread serverThread = new Thread(() -> {
+			// This exists separately to the main mock server, as I had a really hard time getting that to send the
+			// chunked responses correctly, flushing the socket each time. This was the only way I was able to replicate
+			// the issue of the client not handling malformed response chunks correctly.
+			try (ServerSocket serverSocket = new ServerSocket(port)) {
+				Socket socket = serverSocket.accept();
+				InputStream is = socket.getInputStream();
+
+				//noinspection ResultOfMethodCallIgnored
+				is.read(new byte[4096]);
+
+				OutputStream os = socket.getOutputStream();
+				os.write("HTTP/1.1 200 OK\r\n".getBytes(StandardCharsets.UTF_8));
+				os.write("Transfer-Encoding: chunked\r\n".getBytes(StandardCharsets.UTF_8));
+				os.write("\r\n".getBytes(StandardCharsets.UTF_8));
+				os.write("lskdu018973t09sylgasjkfg1][]'./.sdlv".getBytes(StandardCharsets.UTF_8));
+				socket.close();
+			} catch (IOException ex) {
+				throw new RuntimeException(ex);
+			}
+		});
+
+		serverThread.setDaemon(true);
+		serverThread.start();
+
+		ResponseSpec spec = WebClient
+				.builder()
+				.clientConnector(connector)
+				.baseUrl("http://localhost:" + port)
+				.build()
+				.post()
+				.headers(headers -> {
+					if (addTransferEncodingHeader) {
+						headers.add(HttpHeaders.TRANSFER_ENCODING, "chunked");
+					}
+				})
+				.retrieve();
+
+		return responseHandler
+				.apply(spec)
+				.doFinally(signal -> serverThread.stop());
+	}
 
 	private void prepareResponse(Consumer<MockResponse> consumer) {
 		MockResponse response = new MockResponse();
@@ -1252,5 +1392,4 @@ public void setContainerValue(T containerValue) {
 			this.containerValue = containerValue;
 		}
 	}
-
 }