Cheat.java

/*
 * Copyright (C) 2017 Square, Inc.
 *
 * Licensed 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 okhttp3.recipes;

import java.io.File;
import java.io.IOException;
import okhttp3.Cache;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class Cheat {
  private final CheatingInterceptor cheatingInterceptor;
  private final OkHttpClient client;

  public Cheat(File cacheDirectory) {
    cheatingInterceptor = new CheatingInterceptor();

    int cacheSize = 10 * 1024 * 1024; // 10 MiB
    client = new OkHttpClient.Builder()
        .addInterceptor(cheatingInterceptor)
        .cache(new Cache(cacheDirectory, cacheSize))
        .build();
  }

  public void run() throws Exception {
    Request request = new Request.Builder()
        .url("https://publicobject.com/helloworld.txt")
        .build();

    // Request 1 seeds the cache.
    try (Response response = client.newCall(request).execute()) {
      System.out.println("Response 1 response:          " + response);
      System.out.println("Response 1 cache response:    " + response.cacheResponse());
    }

    // Request 2 exercises the cache.
    try (Response response = client.newCall(request).execute()) {
      System.out.println("Response 2 response:          " + response);
      System.out.println("Response 2 cache response:    " + response.cacheResponse());
    }

    // Request 3 uses an interceptor to disable the cache. Note that the cheating interceptor breaks
    // call canceling.
    cheatingInterceptor.clientOverride = new OkHttpClient.Builder()
        .cache(null)
        .build();
    try (Response response = client.newCall(request).execute()) {
      System.out.println("Response 3 response:          " + response);
      System.out.println("Response 3 cache response:    " + response.cacheResponse());
    }
  }

  public static void main(String... args) throws Exception {
    new Cheat(new File("Cheat.tmp")).run();
  }

  /** Note that this breaks call canceling. */
  public static class CheatingInterceptor implements Interceptor {
    volatile OkHttpClient clientOverride;

    @Override public Response intercept(Chain chain) throws IOException {
      OkHttpClient override = clientOverride;
      if (override != null) {
        return override.newCall(chain.request()).execute();
      }

      return chain.proceed(chain.request());
    }
  }
}