Add HTTP compression excludeUserAgents property

Closes gh-3363

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -68,6 +68,7 @@ content into your application; rather pick only the properties that you need.
 	server.port=8080
 	server.address= # bind to a specific NIC
 	server.compression.enabled=false # if response compression is enabled
+	server.compression.exclude-user-agents= # list of user-agents to exclude from compression
 	server.compression.mime-types=text/html,text/xml,text/plain,text/css # comma-separated list of MIME types that should be compressed
 	server.compression.min-response-size=2048 # minimum response size that is required for compression to be performed
 	server.context-parameters.*= # Servlet context init parameters, e.g. server.context-parameters.a=alpha

spring-boot/src/main/java/org/springframework/boot/context/embedded/Compression.java

@@ -37,7 +37,12 @@ public class Compression {
 			"text/css" };
 
 	/**
-	 * Minimum response size that is required for compression to be performed
+	 * Comma-separated list of user agents for which responses should not be compressed.
+	 */
+	private String[] excludedUserAgents = null;
+
+	/**
+	 * Minimum response size that is required for compression to be performed.
 	 */
 	private int minResponseSize = 2048;
 
@@ -65,4 +70,11 @@ public class Compression {
 		this.minResponseSize = minSize;
 	}
 
+	public String[] getExcludedUserAgents() {
+		return this.excludedUserAgents;
+	}
+
+	public void setExcludedUserAgents(String[] excludedUserAgents) {
+		this.excludedUserAgents = excludedUserAgents;
+	}
 }

spring-boot/src/main/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactory.java

@@ -588,6 +588,12 @@ public class JettyEmbeddedServletContainerFactory extends
 						.invoke(handler,
 								new HashSet<String>(Arrays.asList(compression
 										.getMimeTypes())));
+				if (compression.getExcludedUserAgents() != null) {
+					ReflectionUtils.findMethod(handlerClass, "setExcluded", Set.class)
+							.invoke(handler,
+									new HashSet<String>(Arrays.asList(compression
+											.getExcludedUserAgents())));
+				}
 				return handler;
 			}
 			catch (Exception ex) {
@@ -605,6 +611,10 @@ public class JettyEmbeddedServletContainerFactory extends
 			gzipHandler.setMinGzipSize(compression.getMinResponseSize());
 			gzipHandler.setMimeTypes(new HashSet<String>(Arrays.asList(compression
 					.getMimeTypes())));
+			if (compression.getExcludedUserAgents() != null) {
+				gzipHandler.setExcluded(new HashSet<String>(Arrays.asList(compression
+						.getExcludedUserAgents())));
+			}
 			return gzipHandler;
 		}
 
@@ -623,6 +633,11 @@ public class JettyEmbeddedServletContainerFactory extends
 				ReflectionUtils.findMethod(handlerClass, "setIncludedMimeTypes",
 						String[].class).invoke(handler,
 						new Object[] { compression.getMimeTypes() });
+				if (compression.getExcludedUserAgents() != null) {
+					ReflectionUtils.findMethod(handlerClass, "setExcludedAgentPatterns",
+							String[].class).invoke(handler,
+							new Object[] { compression.getExcludedUserAgents() });
+				}
 				return handler;
 			}
 			catch (Exception ex) {

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactory.java

@@ -280,6 +280,11 @@ public class TomcatEmbeddedServletContainerFactory extends
 			protocol.setCompressionMinSize(compression.getMinResponseSize());
 			protocol.setCompressableMimeTypes(StringUtils
 					.arrayToCommaDelimitedString(compression.getMimeTypes()));
+			if (getCompression().getExcludedUserAgents() != null) {
+				protocol.setNoCompressionUserAgents(StringUtils
+						.arrayToCommaDelimitedString(getCompression()
+								.getExcludedUserAgents()));
+			}
 		}
 	}
 

spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainer.java

@@ -19,6 +19,7 @@ package org.springframework.boot.context.embedded.undertow;
 import io.undertow.Handlers;
 import io.undertow.Undertow;
 import io.undertow.Undertow.Builder;
+import io.undertow.attribute.RequestHeaderAttribute;
 import io.undertow.predicate.Predicate;
 import io.undertow.predicate.Predicates;
 import io.undertow.server.HttpHandler;
@@ -27,6 +28,7 @@ import io.undertow.server.handlers.encoding.ContentEncodingRepository;
 import io.undertow.server.handlers.encoding.EncodingHandler;
 import io.undertow.server.handlers.encoding.GzipEncodingProvider;
 import io.undertow.servlet.api.DeploymentManager;
+import io.undertow.util.HttpString;
 
 import java.lang.reflect.Field;
 import java.net.ServerSocket;
@@ -100,8 +102,8 @@ public class UndertowEmbeddedServletContainer implements EmbeddedServletContaine
 
 	private Undertow createUndertowServer() {
 		try {
-			HttpHandler servletHandler = this.manager.start();
-			this.builder.setHandler(getContextHandler(servletHandler));
+			HttpHandler httpHandler = this.manager.start();
+			this.builder.setHandler(getContextHandler(httpHandler));
 			return this.builder.build();
 		}
 		catch (ServletException ex) {
@@ -110,25 +112,36 @@ public class UndertowEmbeddedServletContainer implements EmbeddedServletContaine
 		}
 	}
 
-	private HttpHandler getContextHandler(HttpHandler servletHandler) {
-		HttpHandler contextHandler = configurationCompressionIfNecessary(servletHandler);
+	private HttpHandler getContextHandler(HttpHandler httpHandler) {
+		HttpHandler contextHandler = configurationCompressionIfNecessary(httpHandler);
 		if (StringUtils.isEmpty(this.contextPath)) {
 			return contextHandler;
 		}
 		return Handlers.path().addPrefixPath(this.contextPath, contextHandler);
 	}
 
-	private HttpHandler configurationCompressionIfNecessary(HttpHandler servletHandler) {
+	private HttpHandler configurationCompressionIfNecessary(HttpHandler httpHandler) {
 		if (this.compression == null || !this.compression.getEnabled()) {
-			return servletHandler;
+			return httpHandler;
 		}
-		ContentEncodingRepository encodingRepository = new ContentEncodingRepository();
-		Predicate mimeAndSizePredicate = Predicates.and(Predicates
-				.maxContentSize(this.compression.getMinResponseSize()), Predicates
-				.or(new CompressibleMimeTypePredicate(this.compression.getMimeTypes())));
-		encodingRepository.addEncodingHandler("gzip", new GzipEncodingProvider(), 50,
-				mimeAndSizePredicate);
-		return new EncodingHandler(encodingRepository).setNext(servletHandler);
+		ContentEncodingRepository repository = new ContentEncodingRepository();
+		repository.addEncodingHandler("gzip", new GzipEncodingProvider(), 50,
+				Predicates.and(getCompressionPredicates(this.compression)));
+		return new EncodingHandler(repository).setNext(httpHandler);
+	}
+
+	private Predicate[] getCompressionPredicates(Compression compression) {
+		List<Predicate> predicates = new ArrayList<Predicate>();
+		predicates.add(Predicates.maxContentSize(compression.getMinResponseSize()));
+		predicates.add(new CompressibleMimeTypePredicate(compression.getMimeTypes()));
+		if (compression.getExcludedUserAgents() != null) {
+			for (String agent : compression.getExcludedUserAgents()) {
+				RequestHeaderAttribute agentHeader = new RequestHeaderAttribute(
+						new HttpString(HttpHeaders.USER_AGENT));
+				predicates.add(Predicates.not(Predicates.regex(agentHeader, agent)));
+			}
+		}
+		return predicates.toArray(new Predicate[predicates.size()]);
 	}
 
 	private String getPortsDescription() {

spring-boot/src/test/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactoryTests.java

@@ -531,35 +531,43 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 
 	@Test
 	public void compression() throws Exception {
-		assertTrue(doTestCompression(10000, null));
+		assertTrue(doTestCompression(10000, null, null));
 	}
 
 	@Test
 	public void noCompressionForSmallResponse() throws Exception {
-		assertFalse(doTestCompression(100, null));
+		assertFalse(doTestCompression(100, null, null));
 	}
 
 	@Test
 	public void noCompressionForMimeType() throws Exception {
 		String[] mimeTypes = new String[] { "text/html", "text/xml", "text/css" };
-		assertFalse(doTestCompression(10000, mimeTypes));
+		assertFalse(doTestCompression(10000, mimeTypes, null));
 	}
 
-	private boolean doTestCompression(int contentSize, String[] mimeTypes)
-			throws Exception {
-		String testContent = setUpFactoryForCompression(contentSize, mimeTypes);
+	@Test
+	public void noCompressionForUserAgent() throws Exception {
+		assertFalse(doTestCompression(10000, null, new String[] { "testUserAgent" }));
+	}
+
+	private boolean doTestCompression(int contentSize, String[] mimeTypes,
+			String[] excludedUserAgents) throws Exception {
+		String testContent = setUpFactoryForCompression(contentSize, mimeTypes,
+				excludedUserAgents);
 		TestGzipInputStreamFactory inputStreamFactory = new TestGzipInputStreamFactory();
 		Map<String, InputStreamFactory> contentDecoderMap = singletonMap("gzip",
 				(InputStreamFactory) inputStreamFactory);
-		String response = getResponse(getLocalUrl("/test.txt"),
+		String response = getResponse(
+				getLocalUrl("/test.txt"),
 				new HttpComponentsClientHttpRequestFactory(HttpClientBuilder.create()
+						.setUserAgent("testUserAgent")
 						.setContentDecoderRegistry(contentDecoderMap).build()));
 		assertThat(response, equalTo(testContent));
 		return inputStreamFactory.wasCompressionUsed();
 	}
 
-	protected String setUpFactoryForCompression(int contentSize, String[] mimeTypes)
-			throws Exception {
+	protected String setUpFactoryForCompression(int contentSize, String[] mimeTypes,
+			String[] excludedUserAgents) throws Exception {
 		char[] chars = new char[contentSize];
 		Arrays.fill(chars, 'F');
 		String testContent = new String(chars);
@@ -572,6 +580,9 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 		if (mimeTypes != null) {
 			compression.setMimeTypes(mimeTypes);
 		}
+		if (excludedUserAgents != null) {
+			compression.setExcludedUserAgents(excludedUserAgents);
+		}
 		factory.setCompression(compression);
 		this.container = factory.getEmbeddedServletContainer();
 		this.container.start();

spring-boot/src/test/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactoryTests.java

@@ -186,8 +186,8 @@ public class JettyEmbeddedServletContainerFactoryTests extends
 	@Override
 	@SuppressWarnings("serial")
 	// Workaround for Jetty issue - https://bugs.eclipse.org/bugs/show_bug.cgi?id=470646
-	protected String setUpFactoryForCompression(final int contentSize, String[] mimeTypes)
-			throws Exception {
+	protected String setUpFactoryForCompression(final int contentSize,
+			String[] mimeTypes, String[] excludedUserAgents) throws Exception {
 		char[] chars = new char[contentSize];
 		Arrays.fill(chars, 'F');
 		final String testContent = new String(chars);
@@ -197,6 +197,9 @@ public class JettyEmbeddedServletContainerFactoryTests extends
 		if (mimeTypes != null) {
 			compression.setMimeTypes(mimeTypes);
 		}
+		if (excludedUserAgents != null) {
+			compression.setExcludedUserAgents(excludedUserAgents);
+		}
 		factory.setCompression(compression);
 		this.container = factory.getEmbeddedServletContainer(new ServletRegistrationBean(
 				new HttpServlet() {