Add a http snoop server sample (#2883)

Add a `http snoop server` sample which receives any request and tells the client the details of the request in a formatted string

Related to #761

Co-authored-by: Violeta Georgieva <violetag@vmware.com>
Co-authored-by: Pierre De Rop <pderop@vmware.com>

reactor-netty-examples/src/main/java/reactor/netty/examples/http/snoop/HttpSnoopClient.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2023 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * 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 reactor.netty.examples.http.snoop;
+
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaderValues;
+import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
+import reactor.core.publisher.Mono;
+import reactor.netty.ByteBufMono;
+import reactor.netty.http.Http11SslContextSpec;
+import reactor.netty.http.client.HttpClient;
+
+/**
+ * An HTTP client demo that sends two requests to the http snoop server and then waits for the completion of the two requests
+ *
+ * @author Kun.Long
+ * @see HttpSnoopServer
+ **/
+public class HttpSnoopClient {
+
+	static final boolean SECURE = System.getProperty("secure") != null;
+	static final int PORT = Integer.parseInt(System.getProperty("port", SECURE ? "8443" : "8080"));
+	static final boolean WIRETAP = System.getProperty("wiretap") != null;
+	static final boolean COMPRESS = System.getProperty("compress") != null;
+
+	public static void main(String[] args) throws Exception {
+		HttpClient client = HttpClient.create()
+		                              .port(PORT)
+		                              .wiretap(WIRETAP)
+		                              .compress(COMPRESS);
+		if (SECURE) {
+			Http11SslContextSpec http11SslContextSpec =
+					Http11SslContextSpec.forClient()
+					                    .configure(builder -> builder.trustManager(InsecureTrustManagerFactory.INSTANCE));
+			client = client.secure(spec -> spec.sslContext(http11SslContextSpec));
+		}
+
+		// we fire two requests to the server asynchronously
+		Mono<String> respOfGet =
+				client.headers(hds -> hds.set(HttpHeaderNames.CONTENT_TYPE, HttpHeaderValues.TEXT_PLAIN))
+				      .get()
+				      .uri("/hello?q1=a&q2=b")
+				      .responseContent()
+				      .aggregate()
+				      .asString()
+				      .doOnNext(resp -> System.out.println("resp of get(): \n" + resp));
+		Mono<String> respOfPost =
+				client.headers(hds -> hds.set(HttpHeaderNames.CONTENT_TYPE, HttpHeaderValues.APPLICATION_JSON))
+				      .post()
+				      .uri("/hello2")
+				      .send(ByteBufMono.fromString(Mono.just("{\"foo\": 1,\"bar\": 2}")))
+				      .responseContent()
+				      .aggregate()
+				      .asString()
+				      .doOnNext(resp -> System.out.println("resp of post(): \n" + resp));
+		System.out.println("requests have fired");
+
+		// then let the main thread wait for the completion of the two requests
+		Mono.when(respOfGet, respOfPost).block();
+		System.out.println("main thread exits");
+	}
+}

reactor-netty-examples/src/main/java/reactor/netty/examples/http/snoop/HttpSnoopServer.java

@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) 2023 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * 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 reactor.netty.examples.http.snoop;
+
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaderValues;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http.QueryStringDecoder;
+import io.netty.handler.ssl.util.SelfSignedCertificate;
+import reactor.core.publisher.Mono;
+import reactor.netty.NettyOutbound;
+import reactor.netty.http.Http11SslContextSpec;
+import reactor.netty.http.Http2SslContextSpec;
+import reactor.netty.http.HttpProtocol;
+import reactor.netty.http.server.HttpServer;
+import reactor.netty.http.server.HttpServerRequest;
+import reactor.netty.http.server.HttpServerResponse;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * An HTTP server that receives any request and tells the client the details of the request in a formatted string.
+ *
+ * @author Kun.Long
+ **/
+public class HttpSnoopServer {
+
+	static final boolean SECURE = System.getProperty("secure") != null;
+	static final int PORT = Integer.parseInt(System.getProperty("port", SECURE ? "8443" : "8080"));
+	static final boolean WIRETAP = System.getProperty("wiretap") != null;
+	static final boolean COMPRESS = System.getProperty("compress") != null;
+	static final boolean HTTP2 = System.getProperty("http2") != null;
+
+	public static void main(String[] args) throws Exception {
+		// 1.create and config the server instance
+		HttpServer server = HttpServer.create()
+		                              .port(PORT)
+		                              .wiretap(WIRETAP)
+		                              .compress(COMPRESS);
+
+		if (SECURE) {
+			SelfSignedCertificate ssc = new SelfSignedCertificate();
+			if (HTTP2) {
+				server = server.secure(spec -> spec.sslContext(Http2SslContextSpec.forServer(ssc.certificate(), ssc.privateKey())));
+			}
+			else {
+				server = server.secure(spec -> spec.sslContext(Http11SslContextSpec.forServer(ssc.certificate(), ssc.privateKey())));
+			}
+		}
+		if (HTTP2) {
+			server = server.protocol(HttpProtocol.H2);
+		}
+
+		// 2.config the route rule, this server will receive any request that has any path and any method,
+		// and then send back the details of the received HTTP request
+		server = server.route(routes -> routes.route(
+				req -> true,
+				HttpSnoopServer::parseRequestAndSendResponse
+		));
+
+		// 3. start the server and block the main thread to keep the server running
+		server.bindNow().onDispose().block();
+	}
+
+	private static NettyOutbound parseRequestAndSendResponse(HttpServerRequest request, HttpServerResponse response) {
+		StringBuilder buf = new StringBuilder();
+		buf.append("request received, the details are: \n\n");
+
+		// append the request method, uri and protocol version
+		buf.append("your host: ").append(request.hostAddress()).append("\n");
+		buf.append("http method: ").append(request.method().name()).append("\n");
+		buf.append("http version: ").append(request.version().text()).append("\n");
+		buf.append("request path: ").append(request.path()).append("\n\n");
+
+		// append the request headers
+		buf.append("headers: \n");
+		request.requestHeaders().forEach(entry -> {
+			buf.append(entry.getKey());
+			buf.append(" : ");
+			buf.append(entry.getValue());
+			buf.append("\n");
+		});
+		buf.append("\n");
+
+		// append the query parameters
+		buf.append("query parameters: \n");
+		new QueryStringDecoder(request.uri()).parameters().forEach((key, value) -> {
+			buf.append(key);
+			buf.append(" : ");
+			buf.append(value);
+			buf.append("\n");
+		});
+		buf.append("\n");
+
+		// append the request content if there is any
+		buf.append("content: \n");
+		String contentType = request.requestHeaders().get(HttpHeaderNames.CONTENT_TYPE);
+		Mono<String> responseContent;
+		if (isATextualContentType(contentType)) {
+			responseContent = request.receive().aggregate().asString()
+				   .onErrorResume(e -> {
+					   System.out.println("error occurs when receiving the content: " + e.getMessage());
+					   return Mono.empty();
+				   })
+				   .switchIfEmpty(Mono.just(""))
+			       .map(content -> {
+						buf.append(content);
+						buf.append("\n");
+						return buf.toString();
+					});
+		}
+		else {
+			buf.append("there is no content or the content is not textual, so we don't print it here\n");
+			responseContent = Mono.just(buf.toString());
+		}
+
+		// 6. send the response
+		response.status(HttpResponseStatus.OK);
+		response.header(HttpHeaderNames.CONTENT_TYPE, HttpHeaderValues.TEXT_PLAIN);
+
+		return response.sendString(responseContent);
+	}
+
+	/**
+	 * check whether the content type is textual
+	 **/
+	private static boolean isATextualContentType(String contentType) {
+		if (contentType == null) {
+			return false;
+		}
+
+		for (String textBaseContentType : TEXTUAL_CONTENT_TYPE) {
+			if (contentType.startsWith(textBaseContentType)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	private static final List<String> TEXTUAL_CONTENT_TYPE = Arrays.asList(
+			"text/plain",
+			"text/html",
+			"text/xml",
+			"text/css",
+			"text/javascript",
+			"application/json",
+			"application/xml",
+			"application/javascript",
+			"application/x-javascript",
+			"application/xhtml+xml",
+			"application/x-www-form-urlencoded"
+	);
+}