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    * ====================================================================
    * 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;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.OutputStream;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.zip.Deflater;
  import java.util.zip.GZIPOutputStream;
  
  import org.apache.hc.client5.http.classic.methods.HttpGet;
  import org.apache.hc.client5.http.impl.classic.BasicHttpClientResponseHandler;
  import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
  import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManager;
  import org.apache.hc.client5.testing.extension.sync.ClientProtocolLevel;
  import org.apache.hc.client5.testing.extension.sync.TestClient;
  import org.apache.hc.core5.http.HeaderElement;
  import org.apache.hc.core5.http.HttpHost;
  import org.apache.hc.core5.http.HttpStatus;
  import org.apache.hc.core5.http.URIScheme;
  import org.apache.hc.core5.http.io.HttpRequestHandler;
  import org.apache.hc.core5.http.io.entity.EntityUtils;
  import org.apache.hc.core5.http.io.entity.InputStreamEntity;
  import org.apache.hc.core5.http.io.entity.StringEntity;
  import org.apache.hc.core5.http.message.MessageSupport;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  
  /**
   * Test case for how Content Codings are processed. By default, we want to do the right thing and
   * require no intervention from the user of HttpClient, but we still want to let clients do their
   * own thing if they so wish.
   */
  abstract  class TestContentCodings extends AbstractIntegrationTestBase {
  
      protected TestContentCodings(final URIScheme scheme) {
          super(scheme, ClientProtocolLevel.STANDARD);
      }
  
      /**
       * Test for when we don't get an entity back; e.g. for a 204 or 304 response; nothing blows
       * up with the new behaviour.
       *
       * @throws Exception
       *             if there was a problem
       */
      @Test
      void testResponseWithNoContent() throws Exception {
          configureServer(bootstrap -> bootstrap
                  .register("*", (request, response, context) -> response.setCode(HttpStatus.SC_NO_CONTENT)));
  
          final HttpHost target = startServer();
  
          final TestClient client = client();
  
          final HttpGet request = new HttpGet("/some-resource");
          client.execute(target, request, response -> {
              Assertions.assertEquals(HttpStatus.SC_NO_CONTENT, response.getCode());
              Assertions.assertNull(response.getEntity());
              return null;
          });
      }
  
      /**
       * Test for when we are handling content from a server that has correctly interpreted RFC2616
       * to return RFC1950 streams for {@code deflate} content coding.
       *
      * @throws Exception
      */
     @Test
     void testDeflateSupportForServerReturningRfc1950Stream() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createDeflateEncodingRequestHandler(entityText, false)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
             Assertions.assertEquals(entityText, EntityUtils.toString(response.getEntity()),
                     "The entity text is correctly transported");
             return null;
         });
     }
 
     /**
      * Test for when we are handling content from a server that has incorrectly interpreted RFC2616
      * to return RFC1951 streams for {@code deflate} content coding.
      *
      * @throws Exception
      */
     @Test
     void testDeflateSupportForServerReturningRfc1951Stream() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createDeflateEncodingRequestHandler(entityText, true)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
             Assertions.assertEquals(entityText, EntityUtils.toString(response.getEntity()),
                     "The entity text is correctly transported");
             return null;
         });
     }
 
     /**
      * Test for a server returning gzipped content.
      *
      * @throws Exception
      */
     @Test
     void testGzipSupport() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createGzipEncodingRequestHandler(entityText)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
             Assertions.assertEquals(entityText, EntityUtils.toString(response.getEntity()),
                     "The entity text is correctly transported");
             return null;
         });
     }
 
     /**
      * Try with a bunch of client threads, to check that it's thread-safe.
      *
      * @throws Exception
      *             if there was a problem
      */
     @Test
     void testThreadSafetyOfContentCodings() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createGzipEncodingRequestHandler(entityText)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
         final PoolingHttpClientConnectionManager connManager = client.getConnectionManager();
 
         /*
          * Create a load of workers which will access the resource. Half will use the default
          * gzip behaviour; half will require identity entity.
          */
         final int clients = 10;
 
         connManager.setMaxTotal(clients);
 
         final ExecutorService executor = Executors.newFixedThreadPool(clients);
 
         final CountDownLatch startGate = new CountDownLatch(1);
         final CountDownLatch endGate = new CountDownLatch(clients);
 
         final List<WorkerTask> workers = new ArrayList<>();
 
         for (int i = 0; i < clients; ++i) {
             workers.add(new WorkerTask(client, target, i % 2 == 0, startGate, endGate));
         }
 
         for (final WorkerTask workerTask : workers) {
 
             /* Set them all in motion, but they will block until we call startGate.countDown(). */
             executor.execute(workerTask);
         }
 
         startGate.countDown();
 
         /* Wait for the workers to complete. */
         endGate.await();
 
         for (final WorkerTask workerTask : workers) {
             if (workerTask.isFailed()) {
                 Assertions.fail("A worker failed");
             }
             Assertions.assertEquals(entityText, workerTask.getText());
         }
     }
 
     @Test
     void testHttpEntityWriteToForGzip() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createGzipEncodingRequestHandler(entityText)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
             final ByteArrayOutputStream out = new ByteArrayOutputStream();
             response.getEntity().writeTo(out);
             Assertions.assertEquals(entityText, out.toString("utf-8"));
             return null;
         });
 
     }
 
     @Test
     void testHttpEntityWriteToForDeflate() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createDeflateEncodingRequestHandler(entityText, true)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         client.execute(target, request, response -> {
             final ByteArrayOutputStream out = new ByteArrayOutputStream();
             response.getEntity().writeTo(out);
             Assertions.assertEquals(entityText, out.toString("utf-8"));
             return out;
         });
     }
 
     @Test
     void gzipResponsesWorkWithBasicResponseHandler() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createGzipEncodingRequestHandler(entityText)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         final String response = client.execute(target, request, new BasicHttpClientResponseHandler());
         Assertions.assertEquals(entityText, response, "The entity text is correctly transported");
     }
 
     @Test
     void deflateResponsesWorkWithBasicResponseHandler() throws Exception {
         final String entityText = "Hello, this is some plain text coming back.";
 
         configureServer(bootstrap -> bootstrap
                 .register("*", createDeflateEncodingRequestHandler(entityText, false)));
 
         final HttpHost target = startServer();
 
         final TestClient client = client();
 
         final HttpGet request = new HttpGet("/some-resource");
         final String response = client.execute(target, request, new BasicHttpClientResponseHandler());
         Assertions.assertEquals(entityText, response, "The entity text is correctly transported");
     }
 
     /**
      * Creates a new {@link HttpRequestHandler} that will attempt to provide a deflate stream
      * Content-Coding.
      *
      * @param entityText
      *            the non-null String entity text to be returned by the server
      * @param rfc1951
      *            if true, then the stream returned will be a raw RFC1951 deflate stream, which
      *            some servers return as a result of misinterpreting the HTTP 1.1 RFC. If false,
      *            then it will return an RFC2616 compliant deflate encoded zlib stream.
      * @return a non-null {@link HttpRequestHandler}
      */
     private HttpRequestHandler createDeflateEncodingRequestHandler(
             final String entityText, final boolean rfc1951) {
         return (request, response, context) -> {
             response.setEntity(new StringEntity(entityText));
             response.addHeader("Content-Type", "text/plain");
             final Iterator<HeaderElement> it = MessageSupport.iterate(request, "Accept-Encoding");
             while (it.hasNext()) {
         final HeaderElement element = it.next();
         if ("deflate".equalsIgnoreCase(element.getName())) {
             response.addHeader("Content-Encoding", "deflate");
 
                 /* Gack. DeflaterInputStream is Java 6. */
             // response.setEntity(new InputStreamEntity(new DeflaterInputStream(new
             // ByteArrayInputStream(
             // entityText.getBytes("utf-8"))), -1));
             final byte[] uncompressed = entityText.getBytes(StandardCharsets.UTF_8);
             final Deflater compressor = new Deflater(Deflater.DEFAULT_COMPRESSION, rfc1951);
             compressor.setInput(uncompressed);
             compressor.finish();
             final byte[] output = new byte[100];
             final int compressedLength = compressor.deflate(output);
             final byte[] compressed = new byte[compressedLength];
             System.arraycopy(output, 0, compressed, 0, compressedLength);
             response.setEntity(new InputStreamEntity(
                     new ByteArrayInputStream(compressed), compressedLength, null));
             return;
         }
             }
          };
     }
 
     /**
      * Returns an {@link HttpRequestHandler} implementation that will attempt to provide a gzip
      * Content-Encoding.
      *
      * @param entityText
      *            the non-null String entity to be returned by the server
      * @return a non-null {@link HttpRequestHandler}
      */
     private HttpRequestHandler createGzipEncodingRequestHandler(final String entityText) {
         return (request, response, context) -> {
             response.setEntity(new StringEntity(entityText));
             response.addHeader("Content-Type", "text/plain");
             response.addHeader("Content-Type", "text/plain");
             final Iterator<HeaderElement> it = MessageSupport.iterate(request, "Accept-Encoding");
             while (it.hasNext()) {
         final HeaderElement element = it.next();
         if ("gzip".equalsIgnoreCase(element.getName())) {
             response.addHeader("Content-Encoding", "gzip");
 
             /*
              * We have to do a bit more work with gzip versus deflate, since
              * Gzip doesn't appear to have an equivalent to DeflaterInputStream in
              * the JDK.
              *
              * UPDATE: DeflaterInputStream is Java 6 anyway, so we have to do a bit
              * of work there too!
              */
             final ByteArrayOutputStream bytes = new ByteArrayOutputStream();
             final OutputStream out = new GZIPOutputStream(bytes);
 
             final ByteArrayInputStream uncompressed = new ByteArrayInputStream(
                     entityText.getBytes(StandardCharsets.UTF_8));
 
             final byte[] buf = new byte[60];
 
             int n;
             while ((n = uncompressed.read(buf)) != -1) {
                 out.write(buf, 0, n);
             }
 
             out.close();
 
             final byte[] arr = bytes.toByteArray();
             response.setEntity(new InputStreamEntity(new ByteArrayInputStream(arr),
                     arr.length, null));
 
             return;
         }
             }
          };
     }
 
     /**
      * Sub-ordinate task passed off to a different thread to be executed.
      *
      * @author jabley
      *
      */
     class WorkerTask implements Runnable {
 
         private final CloseableHttpClient client;
         private final HttpHost target;
         private final HttpGet request;
         private final CountDownLatch startGate;
         private final CountDownLatch endGate;
 
         private boolean failed;
         private String text;
 
         WorkerTask(final CloseableHttpClient client, final HttpHost target, final boolean identity, final CountDownLatch startGate, final CountDownLatch endGate) {
             this.client = client;
             this.target = target;
             this.request = new HttpGet("/some-resource");
             if (identity) {
                 request.addHeader("Accept-Encoding", "identity");
             }
             this.startGate = startGate;
             this.endGate = endGate;
         }
 
         /**
          * Returns the text of the HTTP entity.
          *
          * @return a String - may be null.
          */
         public String getText() {
             return this.text;
         }
 
         /**
          * {@inheritDoc}
          */
         @Override
         public void run() {
             try {
                 startGate.await();
                 try {
                     text = client.execute(target, request, response ->
                             EntityUtils.toString(response.getEntity()));
                 } catch (final Exception e) {
                     failed = true;
                 } finally {
                     endGate.countDown();
                 }
             } catch (final InterruptedException ignore) {
             }
         }
 
         /**
          * Returns true if this task failed, otherwise false.
          *
          * @return a flag
          */
         boolean isFailed() {
             return this.failed;
         }
     }
 }