Issue #12397 - Add more default excludes to GzipHandler.

jetty-core/jetty-http/src/main/resources/org/eclipse/jetty/http/mime.properties

@@ -200,3 +200,4 @@ xyz=chemical/x-xyz
 xz=application/x-xz
 z=application/compress
 zip=application/zip
+zst=application/zstd

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/gzip/GzipHandler.java

@@ -85,13 +85,27 @@ else if (type.startsWith("image/") ||
                 type.startsWith("video/"))
                 _mimeTypes.exclude(type);
         }
+
         _mimeTypes.exclude("application/compress");
+        _paths.exclude("*.z");
         _mimeTypes.exclude("application/zip");
+        _paths.exclude("*.zip");
+        _mimeTypes.exclude("application/x-gtar");
+        _paths.exclude("*.tgz");
+        _mimeTypes.exclude("application/java-archive");
+        _paths.exclude("*.jar");
         _mimeTypes.exclude("application/gzip");
+        _paths.exclude("*.gz", "*.gzip");
         _mimeTypes.exclude("application/x-bzip2");
+        _paths.exclude("*.bz2", "*.bzip", "*.bz");
         _mimeTypes.exclude("application/brotli");
+        _paths.exclude("*.br", "*.brotli");
         _mimeTypes.exclude("application/x-xz");
+        _paths.exclude("*.xz");
         _mimeTypes.exclude("application/x-rar-compressed");
+        _paths.exclude("*.rar");
+        _mimeTypes.exclude("application/zstd");
+        _paths.exclude("*.zst", "*.zstd");
 
         // It is possible to use SSE with GzipHandler but you will need to set _synFlush to true which will impact performance.
         _mimeTypes.exclude("text/event-stream");

jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/gzip/GzipHandlerTest.java

@@ -81,6 +81,7 @@
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.CsvSource;
 import org.junit.jupiter.params.provider.MethodSource;
 import org.junit.jupiter.params.provider.ValueSource;
 
@@ -1750,6 +1751,68 @@ public void testSimpleCompressedResponse(int fileSize, WorkDir workDir) throws E
         assertThat("(Uncompressed) Content Hash", metadata.uncompressedSha1Sum, is(expectedSha1Sum));
     }
 
+    /**
+     * Test of default GzipHandler configuration against requests to already compressed content-types.
+     * @param filename
+     */
+    @ParameterizedTest
+    @CsvSource(delimiter = '|', textBlock = """
+        # Filename      | Content-Type
+        example.tar.gz  | application/gzip
+        example.tgz     | application/x-gtar
+        example.zip     | application/zip
+        example.jar     | application/java-archive
+        example.gz      | application/gzip
+        example.bz2     | application/x-bzip2
+        example.rar     | application/x-rar-compressed
+        example.zst     | application/zstd
+        """)
+    public void testDoNotRecompressDefault(String filename, String contentType, WorkDir workDir) throws Exception
+    {
+        Path tmpPath = workDir.getEmptyPathDir();
+        Path contextDir = tmpPath.resolve("context");
+        FS.ensureDirExists(contextDir);
+
+        _contextHandler.setBaseResourceAsPath(contextDir);
+        ResourceHandler resourceHandler = new ResourceHandler();
+        resourceHandler.setEtags(true);
+        _contextHandler.setHandler(resourceHandler);
+
+        int filesize = 2048;
+
+        // Prepare Server File
+        Path file = Files.write(contextDir.resolve(filename), generateContent(filesize));
+        String expectedSha1Sum = Sha1Sum.calculate(file);
+
+        _server.start();
+
+        // Setup request
+        HttpTester.Request request = HttpTester.newRequest();
+        request.setMethod("GET");
+        request.setVersion(HttpVersion.HTTP_1_1);
+        request.setHeader("Host", "tester");
+        request.setHeader("Connection", "close");
+        request.setHeader("Accept-Encoding", "gzip");
+        request.setURI("/ctx/" + filename);
+
+        // Issue request
+        ByteBuffer rawResponse = _connector.getResponse(request.generate(), 5, TimeUnit.SECONDS);
+
+        // Parse response
+        HttpTester.Response response = HttpTester.parseResponse(rawResponse);
+
+        assertThat("Response status", response.getStatus(), is(HttpStatus.OK_200));
+
+        // Response Content-Encoding check
+        assertThat("Response[Content-Encoding]", response.get("Content-Encoding"), nullValue());
+        assertThat("Response[Vary]", response.get("Vary"), nullValue());
+
+        // Response Content checks
+        UncompressedMetadata metadata = parseResponseContent(response);
+        assertThat("(Uncompressed) Content Length", metadata.uncompressedSize, is(filesize));
+        assertThat("(Uncompressed) Content Hash", metadata.uncompressedSha1Sum, is(expectedSha1Sum));
+    }
+
     protected FilterInputStream newContentEncodingFilterInputStream(String contentEncoding, InputStream inputStream) throws IOException
     {
         if (contentEncoding == null)