Add ServerHttpRequest & ServerHttpResponse

This commit introduces HTTP request and response abstractions along
with Servlet-based implementations similar to the ones in the http
package of spring-web but using Reactive Streams.

In turn HttpHandler now accepts the request and response types and
returns Publisher<Void> that reflects the end of handling.

The write method on the response also returns Publisher<Void> allowing
deferred writing. At the moment however the underlying Servlet 3.1
support only supports a single publisher after which the connection
is closed.

Only simple byte[] is supported for reading and writing.

spring-web-reactive/build.gradle

@@ -19,6 +19,7 @@ repositories {
 
 dependencies {
 	compile "org.springframework:spring-core:4.2.0.RELEASE"
+	compile "org.springframework:spring-web:4.2.0.RELEASE"
 	compile "org.reactivestreams:reactive-streams:1.0.0"
 	compile "org.slf4j:slf4j-api:1.7.6"
 	compile "ch.qos.logback:logback-classic:1.1.2"
@@ -26,7 +27,6 @@ dependencies {
 	provided "javax.servlet:javax.servlet-api:3.1.0"
 
 	testCompile "junit:junit:4.12"
-	testCompile "org.springframework:spring-web:4.2.0.RELEASE"
 	testCompile "org.springframework:spring-test:4.2.0.RELEASE"
 
 	testCompile 'org.apache.tomcat:tomcat-util:8.0.24'

spring-web-reactive/src/main/java/org/springframework/reactive/web/HttpHandler.java

@@ -20,9 +20,10 @@ import org.reactivestreams.Publisher;
 
 /**
  * @author Arjen Poutsma
+ * @author Rossen Stoyanchev
  */
 public interface HttpHandler {
 
-	Publisher<byte[]> handle(Publisher<byte[]> request);
+	Publisher<Void> handle(ServerHttpRequest request, ServerHttpResponse response);
 
 }

spring-web-reactive/src/main/java/org/springframework/reactive/web/HttpMessage.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.reactive.web;
+
+import java.net.URI;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+
+/**
+ * @author Rossen Stoyanchev
+ */
+public interface HttpMessage {
+
+	HttpHeaders getHeaders();
+
+}

spring-web-reactive/src/main/java/org/springframework/reactive/web/HttpRequest.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.reactive.web;
+
+import java.net.URI;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+
+/**
+ * @author Rossen Stoyanchev
+ */
+public interface HttpRequest extends HttpMessage {
+
+	HttpMethod getMethod();
+
+	URI getURI();
+
+}

spring-web-reactive/src/main/java/org/springframework/reactive/web/ServerHttpRequest.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.reactive.web;
+
+import org.reactivestreams.Publisher;
+
+/**
+ *
+ * @author Rossen Stoyanchev
+ */
+public interface ServerHttpRequest extends HttpRequest {
+
+	Publisher<byte[]> getBody();
+
+}

spring-web-reactive/src/main/java/org/springframework/reactive/web/ServerHttpResponse.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.reactive.web;
+
+import org.reactivestreams.Publisher;
+
+import org.springframework.http.HttpStatus;
+
+/**
+ * @author Rossen Stoyanchev
+ */
+public interface ServerHttpResponse extends HttpMessage {
+
+	void setStatusCode(HttpStatus status);
+
+	Publisher<Void> writeWith(Publisher<byte[]> contentPublisher);
+
+}

spring-web-reactive/src/main/java/org/springframework/reactive/web/servlet/AsyncContextSynchronizer.java

@@ -97,4 +97,9 @@ final class AsyncContextSynchronizer {
 			this.complete.compareAndSet(NONE_COMPLETE, WRITE_COMPLETE);
 		}
 	}
+
+	public void complete() {
+		readComplete();
+		writeComplete();
+	}
 }

spring-web-reactive/src/main/java/org/springframework/reactive/web/servlet/HttpHandlerServlet.java

@@ -24,41 +24,82 @@ import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import org.reactivestreams.Publisher;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
 
 import org.springframework.reactive.web.HttpHandler;
 
 /**
  * @author Arjen Poutsma
+ * @author Rossen Stoyanchev
  */
 @WebServlet(asyncSupported = true )
 public class HttpHandlerServlet extends HttpServlet {
 
 	private static final int BUFFER_SIZE = 8192;
 
+	private static Log logger = LogFactory.getLog(HttpHandlerServlet.class);
+
+
 	private HttpHandler handler;
 
+
 	public void setHandler(HttpHandler handler) {
 		this.handler = handler;
 	}
 
+
 	@Override
 	protected void service(HttpServletRequest request, HttpServletResponse response)
 			throws ServletException, IOException {
 
 		AsyncContext context = request.startAsync();
-		final AsyncContextSynchronizer contextSynchronizer =
-				new AsyncContextSynchronizer(context);
+		AsyncContextSynchronizer contextSynchronizer = new AsyncContextSynchronizer(context);
 
 		RequestBodyPublisher requestPublisher = new RequestBodyPublisher(contextSynchronizer, BUFFER_SIZE);
 		request.getInputStream().setReadListener(requestPublisher);
+		ServletServerHttpRequest httpRequest = new ServletServerHttpRequest(request, requestPublisher);
 
 		ResponseBodySubscriber responseSubscriber = new ResponseBodySubscriber(contextSynchronizer);
 		response.getOutputStream().setWriteListener(responseSubscriber);
+		ServletServerHttpResponse httpResponse = new ServletServerHttpResponse(response, responseSubscriber);
 
-		Publisher<byte[]> responsePublisher = this.handler.handle(requestPublisher);
-
-		responsePublisher.subscribe(responseSubscriber);
+		HandlerResultSubscriber resultSubscriber = new HandlerResultSubscriber(contextSynchronizer);
+		this.handler.handle(httpRequest, httpResponse).subscribe(resultSubscriber);
 	}
 
+
+	private static class HandlerResultSubscriber implements Subscriber<Void> {
+
+		private final AsyncContextSynchronizer synchronizer;
+
+
+		public HandlerResultSubscriber(AsyncContextSynchronizer synchronizer) {
+			this.synchronizer = synchronizer;
+		}
+
+
+		@Override
+		public void onSubscribe(Subscription subscription) {
+			subscription.request(Long.MAX_VALUE);
+		}
+
+		@Override
+		public void onNext(Void aVoid) {
+			// no op
+		}
+
+		@Override
+		public void onError(Throwable ex) {
+			logger.error("Error from request handling. Completing the request.", ex);
+			this.synchronizer.complete();
+		}
+
+		@Override
+		public void onComplete() {
+			this.synchronizer.complete();
+		}
+	}
 }

spring-web-reactive/src/main/java/org/springframework/reactive/web/servlet/ServletServerHttpRequest.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.reactive.web.servlet;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.charset.Charset;
+import java.util.Enumeration;
+import java.util.Map;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.reactivestreams.Publisher;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.reactive.web.ServerHttpRequest;
+import org.springframework.util.Assert;
+import org.springframework.util.LinkedCaseInsensitiveMap;
+import org.springframework.util.StringUtils;
+
+/**
+ * @author Rossen Stoyanchev
+ */
+public class ServletServerHttpRequest implements ServerHttpRequest {
+
+	private final HttpServletRequest servletRequest;
+
+	private final Publisher<byte[]> requestBodyPublisher;
+
+	private HttpHeaders headers;
+
+
+	public ServletServerHttpRequest(HttpServletRequest servletRequest, Publisher<byte[]> requestBodyPublisher) {
+		Assert.notNull(servletRequest, "HttpServletRequest must not be null");
+		this.servletRequest = servletRequest;
+		this.requestBodyPublisher = requestBodyPublisher;
+	}
+
+
+	@Override
+	public HttpMethod getMethod() {
+		return HttpMethod.valueOf(this.servletRequest.getMethod());
+	}
+
+	@Override
+	public URI getURI() {
+		try {
+			return new URI(this.servletRequest.getScheme(), null, this.servletRequest.getServerName(),
+					this.servletRequest.getServerPort(), this.servletRequest.getRequestURI(),
+					this.servletRequest.getQueryString(), null);
+		}
+		catch (URISyntaxException ex) {
+			throw new IllegalStateException("Could not get HttpServletRequest URI: " + ex.getMessage(), ex);
+		}
+	}
+
+	@Override
+	public HttpHeaders getHeaders() {
+		if (this.headers == null) {
+			this.headers = new HttpHeaders();
+			for (Enumeration<?> headerNames = this.servletRequest.getHeaderNames(); headerNames.hasMoreElements();) {
+				String headerName = (String) headerNames.nextElement();
+				for (Enumeration<?> headerValues = this.servletRequest.getHeaders(headerName);
+					 headerValues.hasMoreElements();) {
+					String headerValue = (String) headerValues.nextElement();
+					this.headers.add(headerName, headerValue);
+				}
+			}
+			// HttpServletRequest exposes some headers as properties: we should include those if not already present
+			MediaType contentType = this.headers.getContentType();
+			if (contentType == null) {
+				String requestContentType = this.servletRequest.getContentType();
+				if (StringUtils.hasLength(requestContentType)) {
+					contentType = MediaType.parseMediaType(requestContentType);
+					this.headers.setContentType(contentType);
+				}
+			}
+			if (contentType != null && contentType.getCharSet() == null) {
+				String requestEncoding = this.servletRequest.getCharacterEncoding();
+				if (StringUtils.hasLength(requestEncoding)) {
+					Charset charSet = Charset.forName(requestEncoding);
+					Map<String, String> params = new LinkedCaseInsensitiveMap<>();
+					params.putAll(contentType.getParameters());
+					params.put("charset", charSet.toString());
+					MediaType newContentType = new MediaType(contentType.getType(), contentType.getSubtype(), params);
+					this.headers.setContentType(newContentType);
+				}
+			}
+			if (this.headers.getContentLength() == -1) {
+				int requestContentLength = this.servletRequest.getContentLength();
+				if (requestContentLength != -1) {
+					this.headers.setContentLength(requestContentLength);
+				}
+			}
+		}
+		return this.headers;
+	}
+
+	@Override
+	public Publisher<byte[]> getBody() {
+		return this.requestBodyPublisher;
+	}
+
+}

spring-web-reactive/src/main/java/org/springframework/reactive/web/servlet/ServletServerHttpResponse.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.reactive.web.servlet;
+
+import java.util.List;
+import java.util.Map;
+import javax.servlet.http.HttpServletResponse;
+
+import org.reactivestreams.Publisher;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.reactive.web.ServerHttpResponse;
+import org.springframework.util.Assert;
+
+/**
+ * @author Rossen Stoyanchev
+ */
+public class ServletServerHttpResponse implements ServerHttpResponse {
+
+	private final HttpServletResponse servletResponse;
+
+	private final ResponseBodySubscriber responseSubscriber;
+
+	private final HttpHeaders headers;
+
+	private boolean headersWritten = false;
+
+
+	public ServletServerHttpResponse(HttpServletResponse servletResponse, ResponseBodySubscriber responseSubscriber) {
+		Assert.notNull(servletResponse, "'servletResponse' must not be null");
+		Assert.notNull(responseSubscriber, "'responseSubscriber' must not be null");
+		this.servletResponse = servletResponse;
+		this.responseSubscriber = responseSubscriber;
+		this.headers = new HttpHeaders();
+	}
+
+
+	@Override
+	public void setStatusCode(HttpStatus status) {
+		this.servletResponse.setStatus(status.value());
+	}
+
+	@Override
+	public HttpHeaders getHeaders() {
+		return (this.headersWritten ? HttpHeaders.readOnlyHttpHeaders(this.headers) : this.headers);
+	}
+
+	@Override
+	public Publisher<Void> writeWith(final Publisher<byte[]> contentPublisher) {
+		writeHeaders();
+		return (s -> contentPublisher.subscribe(responseSubscriber));
+	}
+
+	private void writeHeaders() {
+		if (!this.headersWritten) {
+			for (Map.Entry<String, List<String>> entry : this.headers.entrySet()) {
+				String headerName = entry.getKey();
+				for (String headerValue : entry.getValue()) {
+					this.servletResponse.addHeader(headerName, headerValue);
+				}
+			}
+			// HttpServletResponse exposes some headers as properties: we should include those if not already present
+			if (this.servletResponse.getContentType() == null && this.headers.getContentType() != null) {
+				this.servletResponse.setContentType(this.headers.getContentType().toString());
+			}
+			if (this.servletResponse.getCharacterEncoding() == null && this.headers.getContentType() != null &&
+					this.headers.getContentType().getCharSet() != null) {
+				this.servletResponse.setCharacterEncoding(this.headers.getContentType().getCharSet().name());
+			}
+			this.headersWritten = true;
+		}
+	}
+
+}

spring-web-reactive/src/test/java/org/springframework/reactive/web/AbstractHttpHandlerIntegrationTestCase.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.reactive.web.servlet;
+package org.springframework.reactive.web;
 
 import java.net.URI;
 import java.util.Random;
@@ -29,7 +29,7 @@ import org.springframework.web.client.RestTemplate;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 
-public abstract class AbstractHttpHandlerServletIntegrationTestCase {
+public abstract class AbstractHttpHandlerIntegrationTestCase {
 
 	private static final int REQUEST_SIZE = 4096 * 3;
 

spring-web-reactive/src/test/java/org/springframework/reactive/web/CountingHttpHandler.java

@@ -30,8 +30,8 @@ public class CountingHttpHandler implements HttpHandler {
 	private static final Log logger = LogFactory.getLog(CountingHttpHandler.class);
 
 	@Override
-	public Publisher<byte[]> handle(Publisher<byte[]> request) {
-		request.subscribe(new Subscriber<byte[]>() {
+	public Publisher<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
+		request.getBody().subscribe(new Subscriber<byte[]>() {
 			private Subscription subscription;
 
 			private int byteCount = 0;

spring-web-reactive/src/test/java/org/springframework/reactive/web/EchoHandler.java

@@ -24,7 +24,7 @@ import org.reactivestreams.Publisher;
 public class EchoHandler implements HttpHandler {
 
 	@Override
-	public Publisher<byte[]> handle(Publisher<byte[]> request) {
-		return request;
+	public Publisher<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
+		return response.writeWith(request.getBody());
 	}
 }

spring-web-reactive/src/test/java/org/springframework/reactive/web/servlet/HttpHandlerJettyIntegrationTests.java

@@ -23,13 +23,14 @@ import org.eclipse.jetty.servlet.ServletHolder;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
+import org.springframework.reactive.web.AbstractHttpHandlerIntegrationTestCase;
 import org.springframework.reactive.web.EchoHandler;
 
 /**
  * @author Arjen Poutsma
  */
-public class HttpHandlerServletJettyIntegrationTests
-		extends AbstractHttpHandlerServletIntegrationTestCase {
+public class HttpHandlerJettyIntegrationTests
+		extends AbstractHttpHandlerIntegrationTestCase {
 
 	private static Server jettyServer;
 

spring-web-reactive/src/test/java/org/springframework/reactive/web/servlet/HttpHandlerTomcatIntegrationTests.java

@@ -24,12 +24,13 @@ import org.apache.catalina.startup.Tomcat;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
+import org.springframework.reactive.web.AbstractHttpHandlerIntegrationTestCase;
 import org.springframework.reactive.web.EchoHandler;
 
 /**
  * @author Arjen Poutsma
  */
-public class HttpHandlerServletTomcatIntegrationTests extends AbstractHttpHandlerServletIntegrationTestCase {
+public class HttpHandlerTomcatIntegrationTests extends AbstractHttpHandlerIntegrationTestCase {
 
 	private static Tomcat tomcatServer;