Refactoring of #237 and #240

src/main/java/spark/utils/GzipUtils.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2015 - Per Wendel
+ *
+ *  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 spark.utils;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Collections;
+import java.util.zip.GZIPOutputStream;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * GZIP utility class.
+ *
+ * @author Edward Raff
+ * @author Per Wendel
+ */
+public class GzipUtils {
+
+    private static final String ACCEPT_ENCODING = "Accept-Encoding";
+    private static final String CONTENT_ENCODING = "Content-Encoding";
+
+    private static final String GZIP = "gzip";
+
+    // Hide constructor
+    private GzipUtils() {
+
+    }
+
+    /**
+     * Checks if the HTTP request/response accepts and wants GZIP and i that case wraps the response output stream in a
+     * {@link java.util.zip.GZIPOutputStream}.
+     *
+     * @param httpRequest  the HTTP servlet request.
+     * @param httpResponse the HTTP servlet response.
+     * @return if accepted and wanted a {@link java.util.zip.GZIPOutputStream} otherwise the unchanged response
+     * output stream.
+     * @throws IOException in case of IO error.
+     */
+    public static OutputStream checkAndWrap(HttpServletRequest httpRequest, HttpServletResponse httpResponse) throws
+                                                                                                              IOException {
+        OutputStream outputStream = httpResponse.getOutputStream();
+
+        // GZIP Support handled here. First we must ensure that we want to use gzip, and that the client supports gzip
+        boolean acceptsGzip = Collections.list(httpRequest.getHeaders(ACCEPT_ENCODING)).stream().anyMatch(s -> s.contains(GZIP));
+        boolean wantGzip = httpResponse.getHeaders(CONTENT_ENCODING).contains(GZIP);
+
+        if (acceptsGzip && wantGzip) {
+            outputStream = new GZIPOutputStream(outputStream, true);
+        }
+
+        return outputStream;
+    }
+
+}

src/main/java/spark/webserver/BytesSerializer.java

@@ -20,10 +20,15 @@
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
 
+/**
+ * Bytes serializer.
+ *
+ * @author alex
+ */
 public class BytesSerializer extends Serializer {
 
     @Override
-    public boolean canHandle(Object element) {
+    public boolean canProcess(Object element) {
         return element instanceof byte[] || element instanceof ByteBuffer;
     }
 

src/main/java/spark/webserver/DefaultSerializer.java

@@ -21,14 +21,14 @@
 import java.io.UnsupportedEncodingException;
 
 /**
- * Serilizer that writes the result of toString to output in UTF-8 encoding
+ * Serializer that writes the result of toString to output in UTF-8 encoding
  *
- * @author alsoto
+ * @author alex
  */
 public class DefaultSerializer extends Serializer {
 
     @Override
-    public boolean canHandle(Object element) {
+    public boolean canProcess(Object element) {
         return true;
     }
 

src/main/java/spark/webserver/InputStreamSerializer.java

@@ -22,10 +22,15 @@
 
 import spark.utils.IOUtils;
 
+/**
+ * Input stream serializer.
+ *
+ * @author alex
+ */
 public class InputStreamSerializer extends Serializer {
 
     @Override
-    public boolean canHandle(Object element) {
+    public boolean canProcess(Object element) {
         return element instanceof InputStream;
     }
 

src/main/java/spark/webserver/MatcherFilter.java

@@ -17,6 +17,7 @@
 package spark.webserver;
 
 import java.io.IOException;
+import java.io.OutputStream;
 import java.util.List;
 
 import javax.servlet.Filter;
@@ -40,6 +41,7 @@
 import spark.route.HttpMethod;
 import spark.route.RouteMatch;
 import spark.route.SimpleRouteMatcher;
+import spark.utils.GzipUtils;
 
 /**
  * Filter for matching of filters and routes.
@@ -240,7 +242,14 @@ public void doFilter(ServletRequest servletRequest, ServletResponse servletRespo
                 if (httpResponse.getContentType() == null) {
                     httpResponse.setContentType("text/html; charset=utf-8");
                 }
-                serializerChain.process(httpResponse.getOutputStream(), bodyContent);
+
+                // Check if gzip is wanted/accepted and in that case handle that
+                OutputStream outputStream = GzipUtils.checkAndWrap(httpRequest, httpResponse);
+
+                // serialize the body to output stream
+                serializerChain.process(outputStream, bodyContent);
+
+                outputStream.flush();//needed for GZIP stream. NOt sure where the HTTP response actually gets cleaned up
             }
         } else if (chain != null) {
             chain.doFilter(httpRequest, httpResponse);
@@ -253,4 +262,4 @@ public void destroy() {
 
     private static final String NOT_FOUND = "<html><body><h2>404 Not found</h2></body></html>";
     private static final String INTERNAL_ERROR = "<html><body><h2>500 Internal Error</h2></body></html>";
-}
+}

src/main/java/spark/webserver/Serializer.java

@@ -28,12 +28,24 @@ public abstract class Serializer {
 
     private Serializer next;
 
+    /**
+     * Sets the next serializer in the chain.
+     *
+     * @param serializer the next serializer.
+     */
     public void setNext(Serializer serializer) {
         this.next = serializer;
     }
 
+    /**
+     * Wraps {@link spark.webserver.Serializer#process(java.io.OutputStream, Object)} and calls next serializer in chain.
+     *
+     * @param outputStream the output stream.
+     * @param element the element to process.
+     * @throws IOException IOException in case of IO error.
+     */
     public void processElement(OutputStream outputStream, Object element) throws IOException {
-        if (canHandle(element)) {
+        if (canProcess(element)) {
             process(outputStream, element);
         } else {
             if (next != null) {
@@ -42,7 +54,20 @@ public void processElement(OutputStream outputStream, Object element) throws IOE
         }
     }
 
-    public abstract boolean canHandle(Object element);
+    /**
+     * Checks if the serializer implementation can process the element type.
+     *
+     * @param element the element to process.
+     * @return true if the serializer can process the provided element.
+     */
+    public abstract boolean canProcess(Object element);
 
+    /**
+     * Processes the provided element and serializes to output stream.
+     *
+     * @param outputStream the output stream.
+     * @param element      the element.
+     * @throws IOException In the case of IO error.
+     */
     public abstract void process(OutputStream outputStream, Object element) throws IOException;
 }

src/main/java/spark/webserver/SerializerChain.java

@@ -19,10 +19,16 @@
 import java.io.IOException;
 import java.io.OutputStream;
 
+/**
+ * Chain of serializers for the output.
+ */
 public class SerializerChain {
 
     private Serializer root;
 
+    /**
+     * Constructs a serializer chain.
+     */
     public SerializerChain() {
 
         DefaultSerializer defaultSerializer = new DefaultSerializer();
@@ -36,6 +42,13 @@ public SerializerChain() {
         this.root = bytesSerializer;
     }
 
+    /**
+     * Process the output.
+     *
+     * @param outputStream the output stream to write to.
+     * @param element the element to serialize.
+     * @throws IOException in the case of IO error.
+     */
     public void process(OutputStream outputStream, Object element) throws IOException {
         this.root.processElement(outputStream, element);
     }