Recognize & handle brotli compression of the response body

browsermob-core/pom.xml

@@ -245,5 +245,17 @@
             <artifactId>hamcrest-library</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.meteogroup.jbrotli</groupId>
+            <artifactId>jbrotli-servlet</artifactId>
+            <version>0.5.0</version>
+        </dependency>
     </dependencies>
+    <repositories>
+        <repository>
+            <id>bintray-nitram509-jbrotli</id>
+            <name>bintray</name>
+            <url>http://dl.bintray.com/nitram509/jbrotli</url>
+        </repository>
+    </repositories>
 </project>

browsermob-core/src/main/java/net/lightbody/bmp/filters/ServerResponseCaptureFilter.java

@@ -25,6 +25,7 @@
  */
 public class ServerResponseCaptureFilter extends HttpFiltersAdapter {
     private static final Logger log = LoggerFactory.getLogger(ServerResponseCaptureFilter.class);
+    private static final String BROTLI_COMPRESSION = "br";
 
     /**
      * Populated by serverToProxyResponse() when processing the HttpResponse object
@@ -133,6 +134,13 @@ protected void decompressContents() {
             } catch (RuntimeException e) {
                 log.warn("Failed to decompress response with encoding type " + contentEncoding + " when decoding request from " + originalRequest.getUri(), e);
             }
+        } else if(contentEncoding.equals(BROTLI_COMPRESSION)) {
+            try {
+                fullResponseContents = BrowserMobHttpUtil.decompressBrotliContents(getRawResponseContents());
+                decompressionSuccessful = true;
+            } catch (RuntimeException e) {
+                log.warn("Failed to decompress response with encoding type " + contentEncoding + " when decoding request from " + originalRequest.getUri(), e);
+            }
         } else {
             log.warn("Cannot decode unsupported content encoding type {}", contentEncoding);
         }

browsermob-core/src/main/java/net/lightbody/bmp/util/BrowserMobHttpUtil.java

@@ -9,12 +9,15 @@
 import io.netty.handler.codec.http.HttpResponse;
 import net.lightbody.bmp.exception.DecompressionException;
 import net.lightbody.bmp.exception.UnsupportedCharsetException;
+import org.meteogroup.jbrotli.io.BrotliInputStream;
+import org.meteogroup.jbrotli.libloader.BrotliLibraryLoader;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.nio.charset.Charset;
@@ -111,6 +114,47 @@ public static byte[] decompressContents(byte[] fullMessage) throws Decompression
         return fullMessage;
     }
 
+    /**
+     * Decompresses the brotli byte stream.
+     *
+     * @param fullMessage brotli byte stream to decompress
+     * @return decompressed bytes
+     * @throws DecompressionException thrown if the fullMessage cannot be read or decompressed for any reason
+     */
+    public static byte[] decompressBrotliContents(byte[] fullMessage) throws DecompressionException {
+        BrotliLibraryLoader.loadBrotli();
+
+        InputStream brotliInputReader = null;
+        ByteArrayOutputStream uncompressed = null;
+
+        try {
+            brotliInputReader = new BrotliInputStream(new ByteArrayInputStream(fullMessage));
+
+            uncompressed = new ByteArrayOutputStream();
+
+            byte[] decompressBuffer = new byte[DECOMPRESS_BUFFER_SIZE];
+            int bytesRead;
+            while ((bytesRead = brotliInputReader.read(decompressBuffer, 0, decompressBuffer.length)) != -1) {
+                uncompressed.write(decompressBuffer, 0, bytesRead);
+            }
+
+            uncompressed.flush();
+            fullMessage = uncompressed.toByteArray();
+        } catch (IOException e) {
+            throw new DecompressionException("Unable to decompress response", e);
+        } finally {
+            try {
+                if (brotliInputReader != null) {
+                    brotliInputReader.close();
+                }
+            } catch (IOException e) {
+                log.warn("Unable to close brotli stream", e);
+            }
+        }
+
+        return fullMessage;
+    }
+
     /**
      * Returns true if the content type string indicates textual content. Currently these are any Content-Types that start with one of the
      * following: