code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC 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.
  
  package org.openqa.selenium.grid.testing;
  
  import java.io.IOException;
  import java.io.UncheckedIOException;
  import org.openqa.selenium.remote.http.ClientConfig;
  import org.openqa.selenium.remote.http.HttpClient;
  import org.openqa.selenium.remote.http.HttpRequest;
  import org.openqa.selenium.remote.http.HttpResponse;
  import org.openqa.selenium.remote.http.Routable;
  import org.openqa.selenium.remote.http.WebSocket;
  
  public class PassthroughHttpClient implements HttpClient {
  
    private final Routable handler;
  
    public PassthroughHttpClient(Routable handler) {
      this.handler = handler;
    }
  
    @Override
    public HttpResponse execute(HttpRequest request) {
      if (!handler.matches(request)) {
        throw new UncheckedIOException(new IOException("Doomed"));
      }
  
      return handler.execute(request);
    }
  
    @Override
    public WebSocket openSocket(HttpRequest request, WebSocket.Listener listener) {
      throw new UnsupportedOperationException("openSocket");
    }
  
    public static class Factory implements HttpClient.Factory {
  
      private final Routable handler;
  
      public Factory(Routable handler) {
        this.handler = handler;
      }
  
      public HttpClient createClient(ClientConfig config) {
        return new PassthroughHttpClient(config.filter().andFinally(handler));
      }
  
      @Override
      public void cleanupIdleClients() {
        // Does nothing
      }
    }
  }
  