ServletHttpHandlerAdapter supports Serlvet path mapping

Issue: SPR-16155

spring-web/src/main/java/org/springframework/http/server/reactive/ServletHttpHandlerAdapter.java

@@ -17,11 +17,13 @@
 package org.springframework.http.server.reactive;
 
 import java.io.IOException;
+import java.util.Collection;
 import javax.servlet.AsyncContext;
 import javax.servlet.AsyncEvent;
 import javax.servlet.AsyncListener;
 import javax.servlet.Servlet;
 import javax.servlet.ServletConfig;
+import javax.servlet.ServletRegistration;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.annotation.WebServlet;
@@ -62,9 +64,9 @@ public class ServletHttpHandlerAdapter implements Servlet {
 
 	private int bufferSize = DEFAULT_BUFFER_SIZE;
 
+	@Nullable
+	private String servletPath;
 
-	// Servlet is based on blocking I/O, hence the usage of non-direct, heap-based buffers
-	// (i.e. 'false' as constructor argument)
 	private DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory(false);
 
 
@@ -90,6 +92,18 @@ public class ServletHttpHandlerAdapter implements Servlet {
 		return this.bufferSize;
 	}
 
+	/**
+	 * Return the Servlet path under which the Servlet is deployed by checking
+	 * the Servlet registration from {@link #init(ServletConfig)}.
+	 * @return the path, or an empty string if the Servlet is deployed without
+	 * a prefix (i.e. "/" or "/*"), or {@code null} if this method is invoked
+	 * before the {@link #init(ServletConfig)} Servlet container callback.
+	 */
+	@Nullable
+	public String getServletPath() {
+		return this.servletPath;
+	}
+
 	public void setDataBufferFactory(DataBufferFactory dataBufferFactory) {
 		Assert.notNull(dataBufferFactory, "DataBufferFactory must not be null");
 		this.dataBufferFactory = dataBufferFactory;
@@ -100,7 +114,40 @@ public class ServletHttpHandlerAdapter implements Servlet {
 	}
 
 
-	// The Servlet.service method
+	// Servlet methods...
+
+	@Override
+	public void init(ServletConfig config) {
+		this.servletPath = getServletPath(config);
+	}
+
+	@Nullable
+	private String getServletPath(ServletConfig config) {
+		String name = config.getServletName();
+		ServletRegistration registration = config.getServletContext().getServletRegistration(name);
+		Assert.notNull(registration, "ServletRegistration not found for Servlet '" + name + "'.");
+
+		Collection<String> mappings = registration.getMappings();
+		if (mappings.size() == 1) {
+			String mapping = mappings.iterator().next();
+			if (mapping.equals("/")) {
+				return "";
+			}
+			if (mapping.endsWith("/*")) {
+				String path = mapping.substring(0, mapping.length() - 2);
+				if (!path.isEmpty()) {
+					logger.info("Found Servlet mapping '" + path + "' for Servlet '" + name + "'.");
+				}
+				return path;
+			}
+		}
+
+		throw new IllegalArgumentException("Expected a single Servlet mapping -- " +
+				"either the default Servlet mapping (i.e. '/'), " +
+				"or a path based mapping (e.g. '/*', '/foo/*'). " +
+				"Actual mappings: " + mappings + " for Servlet '" + name + "'.");
+	}
+
 
 	@Override
 	public void service(ServletRequest request, ServletResponse response) throws IOException {
@@ -121,21 +168,24 @@ public class ServletHttpHandlerAdapter implements Servlet {
 		this.httpHandler.handle(httpRequest, httpResponse).subscribe(subscriber);
 	}
 
-	protected ServerHttpRequest createRequest(HttpServletRequest request, AsyncContext context) throws IOException {
-		return new ServletServerHttpRequest(
-				request, context, getDataBufferFactory(), getBufferSize());
-	}
+	protected ServerHttpRequest createRequest(HttpServletRequest request, AsyncContext context)
+			throws IOException {
 
-	protected ServerHttpResponse createResponse(HttpServletResponse response, AsyncContext context) throws IOException {
-		return new ServletServerHttpResponse(
-				response, context, getDataBufferFactory(), getBufferSize());
+		Assert.notNull(this.servletPath, "servletPath is not initialized.");
+
+		return new ServletServerHttpRequest(
+				request, context, this.servletPath, getDataBufferFactory(), getBufferSize());
 	}
 
+	protected ServerHttpResponse createResponse(HttpServletResponse response, AsyncContext context)
+			throws IOException {
 
-	// Other Servlet methods...
+		return new ServletServerHttpResponse(response, context, getDataBufferFactory(), getBufferSize());
+	}
 
 	@Override
-	public void init(ServletConfig config) {
+	public String getServletInfo() {
+		return "";
 	}
 
 	@Override
@@ -144,11 +194,6 @@ public class ServletHttpHandlerAdapter implements Servlet {
 		return null;
 	}
 
-	@Override
-	public String getServletInfo() {
-		return "";
-	}
-
 	@Override
 	public void destroy() {
 	}

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

@@ -70,9 +70,9 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 
 
 	public ServletServerHttpRequest(HttpServletRequest request, AsyncContext asyncContext,
-			DataBufferFactory bufferFactory, int bufferSize) throws IOException {
+			String servletPath, DataBufferFactory bufferFactory, int bufferSize) throws IOException {
 
-		super(initUri(request), request.getContextPath(), initHeaders(request));
+		super(initUri(request), request.getContextPath() + servletPath, initHeaders(request));
 
 		Assert.notNull(bufferFactory, "'bufferFactory' must not be null");
 		Assert.isTrue(bufferSize > 0, "'bufferSize' must be higher than 0");

spring-web/src/main/java/org/springframework/http/server/reactive/TomcatHttpHandlerAdapter.java

@@ -31,6 +31,7 @@ import org.apache.catalina.connector.CoyoteOutputStream;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DataBufferUtils;
+import org.springframework.util.Assert;
 
 /**
  * {@link ServletHttpHandlerAdapter} extension that uses Tomcat APIs for reading
@@ -42,18 +43,25 @@ import org.springframework.core.io.buffer.DataBufferUtils;
 @WebServlet(asyncSupported = true)
 public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
+
 	public TomcatHttpHandlerAdapter(HttpHandler httpHandler) {
 		super(httpHandler);
 	}
 
 
 	@Override
-	protected ServerHttpRequest createRequest(HttpServletRequest request, AsyncContext cxt) throws IOException {
-		return new TomcatServerHttpRequest(request, cxt, getDataBufferFactory(), getBufferSize());
+	protected ServerHttpRequest createRequest(HttpServletRequest request, AsyncContext asyncContext)
+			throws IOException {
+
+		Assert.notNull(getServletPath(), "servletPath is not initialized.");
+		return new TomcatServerHttpRequest(request, asyncContext, getServletPath(),
+				getDataBufferFactory(), getBufferSize());
 	}
 
 	@Override
-	protected ServerHttpResponse createResponse(HttpServletResponse response, AsyncContext cxt) throws IOException {
+	protected ServerHttpResponse createResponse(HttpServletResponse response, AsyncContext cxt)
+			throws IOException {
+
 		return new TomcatServerHttpResponse(response, cxt, getDataBufferFactory(), getBufferSize());
 	}
 
@@ -61,9 +69,9 @@ public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 	private final class TomcatServerHttpRequest extends ServletServerHttpRequest {
 
 		public TomcatServerHttpRequest(HttpServletRequest request, AsyncContext context,
-				DataBufferFactory factory, int bufferSize) throws IOException {
+				String servletPath, DataBufferFactory factory, int bufferSize) throws IOException {
 
-			super(request, context, factory, bufferSize);
+			super(request, context, servletPath, factory, bufferSize);
 		}
 
 		@Override

spring-web/src/test/java/org/springframework/http/server/reactive/ServerHttpRequestTests.java

@@ -93,7 +93,7 @@ public class ServerHttpRequestTests {
 			}
 		};
 		AsyncContext asyncContext = new MockAsyncContext(request, new MockHttpServletResponse());
-		return new ServletServerHttpRequest(request, asyncContext, new DefaultDataBufferFactory(), 1024);
+		return new ServletServerHttpRequest(request, asyncContext, "", new DefaultDataBufferFactory(), 1024);
 	}
 
 	private static class TestServletInputStream extends DelegatingServletInputStream {

spring-web/src/test/java/org/springframework/http/server/reactive/bootstrap/TomcatHttpServer.java

@@ -35,6 +35,10 @@ public class TomcatHttpServer extends AbstractHttpServer {
 
 	private final Class<?> wsListener;
 
+	private String contextPath = "";
+
+	private String servletMapping = "/";
+
 	private Tomcat tomcatServer;
 
 
@@ -49,6 +53,15 @@ public class TomcatHttpServer extends AbstractHttpServer {
 	}
 
 
+	public void setContextPath(String contextPath) {
+		this.contextPath = contextPath;
+	}
+
+	public void setServletMapping(String servletMapping) {
+		this.servletMapping = servletMapping;
+	}
+
+
 	@Override
 	protected void initServer() throws Exception {
 		this.tomcatServer = new Tomcat();
@@ -59,9 +72,9 @@ public class TomcatHttpServer extends AbstractHttpServer {
 		ServletHttpHandlerAdapter servlet = initServletAdapter();
 
 		File base = new File(System.getProperty("java.io.tmpdir"));
-		Context rootContext = tomcatServer.addContext("", base.getAbsolutePath());
+		Context rootContext = tomcatServer.addContext(this.contextPath, base.getAbsolutePath());
 		Tomcat.addServlet(rootContext, "httpHandlerServlet", servlet);
-		rootContext.addServletMappingDecoded("/", "httpHandlerServlet");
+		rootContext.addServletMappingDecoded(this.servletMapping, "httpHandlerServlet");
 		if (wsListener != null) {
 			rootContext.addApplicationListener(wsListener.getName());
 		}

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ContextPathIntegrationTests.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.web.reactive.result.method.annotation;
 
+import java.io.File;
+
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -25,6 +27,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.bootstrap.ReactorHttpServer;
+import org.springframework.http.server.reactive.bootstrap.TomcatHttpServer;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.client.RestTemplate;
@@ -34,76 +37,85 @@ import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
 import static org.junit.Assert.assertEquals;
 
 /**
- * Integration tests that demonstrate running multiple applications under
- * different context paths.
+ * Integration tests related to the use of context paths.
  *
  * @author Rossen Stoyanchev
  */
 @SuppressWarnings({"unused", "WeakerAccess"})
 public class ContextPathIntegrationTests {
 
-	private ReactorHttpServer server;
-
 
-	@Before
-	public void setup() throws Exception {
+	@Test
+	public void multipleWebFluxApps() throws Exception {
 		AnnotationConfigApplicationContext context1 = new AnnotationConfigApplicationContext();
-		context1.register(WebApp1Config.class);
+		context1.register(WebAppConfig.class);
 		context1.refresh();
 
 		AnnotationConfigApplicationContext context2 = new AnnotationConfigApplicationContext();
-		context2.register(WebApp2Config.class);
+		context2.register(WebAppConfig.class);
 		context2.refresh();
 
 		HttpHandler webApp1Handler = WebHttpHandlerBuilder.applicationContext(context1).build();
 		HttpHandler webApp2Handler = WebHttpHandlerBuilder.applicationContext(context2).build();
 
-		this.server = new ReactorHttpServer();
+		ReactorHttpServer server = new ReactorHttpServer();
+		server.registerHttpHandler("/webApp1", webApp1Handler);
+		server.registerHttpHandler("/webApp2", webApp2Handler);
+		server.afterPropertiesSet();
+		server.start();
 
-		this.server.registerHttpHandler("/webApp1", webApp1Handler);
-		this.server.registerHttpHandler("/webApp2", webApp2Handler);
+		try {
+			RestTemplate restTemplate = new RestTemplate();
+			String actual;
 
-		this.server.afterPropertiesSet();
-		this.server.start();
-	}
+			String url = "http://localhost:" + server.getPort() + "/webApp1/test";
+			actual = restTemplate.getForObject(url, String.class);
+			assertEquals("Tested in /webApp1", actual);
 
-	@After
-	public void shutdown() throws Exception {
-		this.server.stop();
+			url = "http://localhost:" + server.getPort() + "/webApp2/test";
+			actual = restTemplate.getForObject(url, String.class);
+			assertEquals("Tested in /webApp2", actual);
+		}
+		finally {
+			server.stop();
+		}
 	}
 
-
 	@Test
-	public void basic() throws Exception {
-		RestTemplate restTemplate = new RestTemplate();
-		String actual;
+	public void servletPathMapping() throws Exception {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.register(WebAppConfig.class);
+		context.refresh();
 
-		actual = restTemplate.getForObject(createUrl("/webApp1/test"), String.class);
-		assertEquals("Tested in /webApp1", actual);
+		File base = new File(System.getProperty("java.io.tmpdir"));
+		TomcatHttpServer server = new TomcatHttpServer(base.getAbsolutePath());
+		server.setContextPath("/app");
+		server.setServletMapping("/api/*");
 
-		actual = restTemplate.getForObject(createUrl("/webApp2/test"), String.class);
-		assertEquals("Tested in /webApp2", actual);
-	}
+		HttpHandler httpHandler = WebHttpHandlerBuilder.applicationContext(context).build();
+		server.setHandler(httpHandler);
 
-	private String createUrl(String path) {
-		return "http://localhost:" + this.server.getPort() + path;
-	}
+		server.afterPropertiesSet();
+		server.start();
 
+		try {
+			RestTemplate restTemplate = new RestTemplate();
+			String actual;
 
-	@EnableWebFlux
-	@Configuration
-	static class WebApp1Config {
-
-		@Bean
-		public TestController testController() {
-			return new TestController();
+			String url = "http://localhost:" + server.getPort() + "/app/api/test";
+			actual = restTemplate.getForObject(url, String.class);
+			assertEquals("Tested in /app/api", actual);
+		}
+		finally {
+			server.stop();
 		}
 	}
 
 
+
 	@EnableWebFlux
 	@Configuration
-	static class WebApp2Config {
+	static class WebAppConfig {
 
 		@Bean
 		public TestController testController() {