[HTTPCLIENT-1843] - Delegate compression handling to Apache Commons Compress

 * Integrated Apache Commons Compress into CompressorFactory to handle compression and decompression of HTTP entities using supported algorithms (gzip, deflate, etc.).

Author: arturobernalg

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/StandardTestClientBuilder.java

@@ -57,6 +57,8 @@ final class StandardTestClientBuilder implements TestClientBuilder {
 
     private HttpClientConnectionManager connectionManager;
 
+    private boolean noWrap;
+
     public StandardTestClientBuilder() {
         this.clientBuilder = HttpClientBuilder.create();
     }
@@ -72,6 +74,12 @@ public TestClientBuilder setTimeout(final Timeout timeout) {
         return this;
     }
 
+    @Override
+    public TestClientBuilder setNoWrap(final boolean noWrap) {
+        this.noWrap = noWrap;
+        return this;
+    }
+
     @Override
     public TestClientBuilder setConnectionManager(final HttpClientConnectionManager connectionManager) {
         this.connectionManager = connectionManager;
@@ -165,6 +173,7 @@ public TestClient build() throws Exception {
 
         final CloseableHttpClient client = clientBuilder
                 .setConnectionManager(connectionManagerCopy)
+                .setNoWrap(noWrap)
                 .build();
         return new TestClient(client, connectionManagerCopy);
     }

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/TestClientBuilder.java

@@ -98,6 +98,10 @@ default TestClientBuilder  addExecInterceptorLast(String name, ExecChainHandler
         throw new UnsupportedOperationException("Operation not supported by " + getProtocolLevel());
     }
 
+    default TestClientBuilder setNoWrap(boolean noWrap){
+        return this;
+    }
+
     TestClient build() throws Exception;
 
 }

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/TestClientResources.java

@@ -118,4 +118,9 @@ public TestClient client() throws Exception {
         return client;
     }
 
+    public TestClient client(final boolean noWrap) throws Exception {
+        clientBuilder.setNoWrap(noWrap);
+        return client();
+    }
+
 }

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/sync/AbstractIntegrationTestBase.java

@@ -78,4 +78,8 @@ public TestClient client() throws Exception {
         return testResources.client();
     }
 
+    public TestClient client(final boolean noWrap) throws Exception {
+        return testResources.client(noWrap);
+    }
+
 }

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/sync/TestContentCodings.java

@@ -108,7 +108,7 @@ void testDeflateSupportForServerReturningRfc1950Stream() throws Exception {
 
         final HttpHost target = startServer();
 
-        final TestClient client = client();
+        final TestClient client = client(true);
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
@@ -133,7 +133,7 @@ void testDeflateSupportForServerReturningRfc1951Stream() throws Exception {
 
         final HttpHost target = startServer();
 
-        final TestClient client = client();
+        final TestClient client = client(false);
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
@@ -289,7 +289,7 @@ void deflateResponsesWorkWithBasicResponseHandler() throws Exception {
 
         final HttpHost target = startServer();
 
-        final TestClient client = client();
+        final TestClient client = client(true);
 
         final HttpGet request = new HttpGet("/some-resource");
         final String response = client.execute(target, request, new BasicHttpClientResponseHandler());

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/sync/TestRedirects.java

@@ -639,8 +639,8 @@ public void handle(final ClassicHttpRequest request,
         Assertions.assertEquals(new URIBuilder().setHttpHost(target).setPath("/random/100").build(),
                 reqWrapper.getUri());
 
-        assertThat(values.poll(), CoreMatchers.equalTo("gzip, x-gzip, deflate"));
-        assertThat(values.poll(), CoreMatchers.equalTo("gzip, x-gzip, deflate"));
+        assertThat(values.poll(), CoreMatchers.equalTo("snappy-raw, xz, snappy-framed, bzip2, lz4-framed, deflate64, br, lzma, zstd, lz4-block, gz, deflate, z, pack200"));
+        assertThat(values.poll(), CoreMatchers.equalTo("snappy-raw, xz, snappy-framed, bzip2, lz4-framed, deflate64, br, lzma, zstd, lz4-block, gz, deflate, z, pack200"));
         assertThat(values.poll(), CoreMatchers.nullValue());
     }
 

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/sync/compress/CompressedResponseHandlingExample.java

@@ -0,0 +1,113 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.hc.client5.testing.sync.compress;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.hc.client5.http.entity.CompressorFactory;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
+import org.apache.hc.client5.http.impl.classic.HttpClients;
+import org.apache.hc.core5.http.ClassicHttpRequest;
+import org.apache.hc.core5.http.ContentType;
+import org.apache.hc.core5.http.HttpEntity;
+import org.apache.hc.core5.http.HttpHeaders;
+import org.apache.hc.core5.http.HttpHost;
+import org.apache.hc.core5.http.io.entity.EntityUtils;
+import org.apache.hc.core5.http.io.entity.StringEntity;
+import org.apache.hc.core5.http.io.support.ClassicRequestBuilder;
+import org.apache.hc.core5.io.CloseMode;
+import org.apache.hc.core5.testing.classic.ClassicTestServer;
+
+
+/**
+ * Demonstrates handling of HTTP responses with content compression using Apache HttpClient.
+ * <p>
+ * This example sets up a local test server that simulates compressed HTTP responses. It then
+ * creates a custom HttpClient configured to handle compression. The client makes a request to
+ * the test server, receives a compressed response, and decompresses the content to verify the
+ * process.
+ * <p>
+ * The main focus of this example is to illustrate the use of a custom HttpClient that can
+ * handle compressed HTTP responses transparently, simulating a real-world scenario where
+ * responses from a server might be compressed to reduce bandwidth usage.
+ */
+public class CompressedResponseHandlingExample {
+
+    public static void main(final String[] args) {
+
+        final ClassicTestServer server = new ClassicTestServer();
+        try {
+            server.register("/compressed", (request, response, context) -> {
+                final String uncompressedContent = "This is the uncompressed response content";
+                response.setEntity(compress(uncompressedContent, "gzip"));
+                response.addHeader(HttpHeaders.CONTENT_ENCODING, "gzip");
+            });
+
+            server.start();
+
+            final HttpHost target = new HttpHost("localhost", server.getPort());
+
+            final List<String> encodingList = Arrays.asList("gz", "deflate");
+
+            try (final CloseableHttpClient httpclient = HttpClients
+                    .custom()
+                    .setEncodings(encodingList)
+                    .build()) {
+                final ClassicHttpRequest httpGet = ClassicRequestBuilder.get()
+                        .setHttpHost(target)
+                        .setPath("/compressed")
+                        .build();
+
+                System.out.println("Executing request " + httpGet.getMethod() + " " + httpGet.getUri());
+                httpclient.execute(httpGet, response -> {
+                    System.out.println("----------------------------------------");
+                    System.out.println(httpGet + "->" + response.getCode() + " " + response.getReasonPhrase());
+
+                    final HttpEntity responseEntity = response.getEntity();
+                    final String responseBody = EntityUtils.toString(responseEntity);
+                    System.out.println("Response content: " + responseBody);
+
+                    return null;
+                });
+            }
+
+        } catch (final Exception e) {
+            e.printStackTrace();
+        } finally {
+            server.shutdown(CloseMode.GRACEFUL);
+        }
+    }
+
+
+    private static HttpEntity compress(final String data, final String name) {
+        final StringEntity originalEntity = new StringEntity(data, ContentType.TEXT_PLAIN);
+        return CompressorFactory.INSTANCE.compressEntity(originalEntity, name);
+    }
+
+}

httpclient5/pom.xml

@@ -97,6 +97,10 @@
       <artifactId>mockito-core</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-compress</artifactId>
+    </dependency>
   </dependencies>
 
   <build>

httpclient5/src/main/java/org/apache/hc/client5/http/entity/BrotliDecompressingEntity.java

@@ -34,7 +34,9 @@
  *
  * @see GzipDecompressingEntity
  * @since 5.2
+ * @deprecated Use {@link CompressorFactory} for handling Brotli decompression.
  */
+@Deprecated
 public class BrotliDecompressingEntity extends DecompressingEntity {
     /**
      * Creates a new {@link DecompressingEntity}.

httpclient5/src/main/java/org/apache/hc/client5/http/entity/BrotliInputStreamFactory.java

@@ -37,7 +37,9 @@
  * {@link InputStreamFactory} for handling Brotli Content Coded responses.
  *
  * @since 5.2
+ * @deprecated Use {@link CompressorFactory} for handling Brotli compression.
  */
+@Deprecated
 @Contract(threading = ThreadingBehavior.STATELESS)
 public class BrotliInputStreamFactory implements InputStreamFactory {
 

httpclient5/src/main/java/org/apache/hc/client5/http/entity/CompressingEntity.java

@@ -0,0 +1,132 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package org.apache.hc.client5.http.entity;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import org.apache.commons.compress.compressors.CompressorException;
+import org.apache.hc.core5.http.HttpEntity;
+import org.apache.hc.core5.http.io.entity.HttpEntityWrapper;
+import org.apache.hc.core5.util.Args;
+
+
+/**
+ * An {@link HttpEntity} wrapper that applies compression to the content before writing it to
+ * an output stream. This class supports various compression algorithms based on the
+ * specified content encoding.
+ *
+ * <p>Compression is performed using {@link CompressorFactory}, which returns a corresponding
+ * {@link OutputStream} for the requested compression type. This class does not support
+ * reading the content directly through {@link #getContent()} as the content is always compressed
+ * during write operations.</p>
+ *
+ * @since 5.5
+ */
+public class CompressingEntity extends HttpEntityWrapper {
+
+    /**
+     * The content encoding type, e.g., "gzip", "deflate", etc.
+     */
+    private final String contentEncoding;
+
+    /**
+     * Creates a new {@link CompressingEntity} that compresses the wrapped entity's content
+     * using the specified content encoding.
+     *
+     * @param entity          the {@link HttpEntity} to wrap and compress; must not be {@code null}.
+     * @param contentEncoding the content encoding to use for compression, e.g., "gzip".
+     */
+    public CompressingEntity(final HttpEntity entity, final String contentEncoding) {
+        super(entity);
+        this.contentEncoding = Args.notNull(contentEncoding, "Content encoding");
+    }
+
+    /**
+     * Returns the content encoding used for compression.
+     *
+     * @return the content encoding (e.g., "gzip", "deflate").
+     */
+    @Override
+    public String getContentEncoding() {
+        return contentEncoding;
+    }
+
+
+    /**
+     * Returns whether the entity is chunked. This is determined by the wrapped entity.
+     *
+     * @return {@code true} if the entity is chunked, {@code false} otherwise.
+     */
+    @Override
+    public boolean isChunked() {
+        return super.isChunked();
+    }
+
+
+    /**
+     * This method is unsupported because the content is meant to be compressed during the
+     * {@link #writeTo(OutputStream)} operation.
+     *
+     * @throws UnsupportedOperationException always, as this method is not supported.
+     */
+    @Override
+    public InputStream getContent() throws IOException {
+        throw new UnsupportedOperationException("Reading content is not supported for CompressingEntity");
+    }
+
+    /**
+     * Writes the compressed content to the provided {@link OutputStream}. Compression is performed
+     * using the content encoding provided during entity construction.
+     *
+     * @param outStream the {@link OutputStream} to which the compressed content will be written; must not be {@code null}.
+     * @throws IOException                   if an I/O error occurs during compression or writing.
+     * @throws UnsupportedOperationException if the specified compression type is not supported.
+     */
+    @Override
+    public void writeTo(final OutputStream outStream) throws IOException {
+        Args.notNull(outStream, "Output stream");
+
+        // Get the compressor based on the specified content encoding
+        final OutputStream compressorStream;
+        try {
+            compressorStream = CompressorFactory.INSTANCE.getCompressorOutputStream(contentEncoding, outStream);
+        } catch (final CompressorException e) {
+            throw new IOException("Error initializing decompression stream", e);
+        }
+
+        if (compressorStream != null) {
+            // Write compressed data
+            super.writeTo(compressorStream);
+            // Close the compressor stream after writing
+            compressorStream.close();
+        } else {
+            throw new UnsupportedOperationException("Unsupported compression: " + contentEncoding);
+        }
+    }
+}