OkHttpNetworkFetcher.java

/*
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.imagepipeline.backends.okhttp3;

import android.net.Uri;
import android.os.Looper;
import android.os.SystemClock;
import com.facebook.common.logging.FLog;
import com.facebook.imagepipeline.image.EncodedImage;
import com.facebook.imagepipeline.producers.BaseNetworkFetcher;
import com.facebook.imagepipeline.producers.BaseProducerContextCallbacks;
import com.facebook.imagepipeline.producers.Consumer;
import com.facebook.imagepipeline.producers.FetchState;
import com.facebook.imagepipeline.producers.ProducerContext;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executor;
import okhttp3.CacheControl;
import okhttp3.Call;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;

/**
 * Network fetcher that uses OkHttp 3 as a backend.
 */
public class OkHttpNetworkFetcher extends
    BaseNetworkFetcher<OkHttpNetworkFetcher.OkHttpNetworkFetchState> {

  public static class OkHttpNetworkFetchState extends FetchState {
    public long submitTime;
    public long responseTime;
    public long fetchCompleteTime;

    public OkHttpNetworkFetchState(
        Consumer<EncodedImage> consumer,
        ProducerContext producerContext) {
      super(consumer, producerContext);
    }
  }

  private static final String TAG = "OkHttpNetworkFetchProducer";
  private static final String QUEUE_TIME = "queue_time";
  private static final String FETCH_TIME = "fetch_time";
  private static final String TOTAL_TIME = "total_time";
  private static final String IMAGE_SIZE = "image_size";

  private final Call.Factory mCallFactory;

  private Executor mCancellationExecutor;

  /**
   * @param okHttpClient client to use
   */
  public OkHttpNetworkFetcher(OkHttpClient okHttpClient) {
    this(okHttpClient, okHttpClient.dispatcher().executorService());
  }

  /**
   * @param callFactory custom {@link Call.Factory} for fetching image from the network
   * @param cancellationExecutor executor on which fetching cancellation is performed if
   * cancellation is requested from the UI Thread
   */
  public OkHttpNetworkFetcher(Call.Factory callFactory, Executor cancellationExecutor) {
    mCallFactory = callFactory;
    mCancellationExecutor = cancellationExecutor;
  }

  @Override
  public OkHttpNetworkFetchState createFetchState(
      Consumer<EncodedImage> consumer,
      ProducerContext context) {
    return new OkHttpNetworkFetchState(consumer, context);
  }

  @Override
  public void fetch(final OkHttpNetworkFetchState fetchState, final Callback callback) {
    fetchState.submitTime = SystemClock.elapsedRealtime();
    final Uri uri = fetchState.getUri();

    try {
      Request request = new Request.Builder()
        .cacheControl(new CacheControl.Builder().noStore().build())
        .url(uri.toString())
        .get()
        .build();

      fetchWithRequest(fetchState, callback, request);
    } catch (Exception e) {
      // handle error while creating the request
      callback.onFailure(e);
    }
  }

  @Override
  public void onFetchCompletion(OkHttpNetworkFetchState fetchState, int byteSize) {
    fetchState.fetchCompleteTime = SystemClock.elapsedRealtime();
  }

  @Override
  public Map<String, String> getExtraMap(OkHttpNetworkFetchState fetchState, int byteSize) {
    Map<String, String> extraMap = new HashMap<>(4);
    extraMap.put(QUEUE_TIME, Long.toString(fetchState.responseTime - fetchState.submitTime));
    extraMap.put(FETCH_TIME, Long.toString(fetchState.fetchCompleteTime - fetchState.responseTime));
    extraMap.put(TOTAL_TIME, Long.toString(fetchState.fetchCompleteTime - fetchState.submitTime));
    extraMap.put(IMAGE_SIZE, Integer.toString(byteSize));
    return extraMap;
  }

  protected void fetchWithRequest(
      final OkHttpNetworkFetchState fetchState,
      final Callback callback,
      final Request request) {
    final Call call = mCallFactory.newCall(request);

    fetchState.getContext().addCallbacks(
        new BaseProducerContextCallbacks() {
          @Override
          public void onCancellationRequested() {
            if (Looper.myLooper() != Looper.getMainLooper()) {
              call.cancel();
            } else {
              mCancellationExecutor.execute(new Runnable() {
                @Override public void run() {
                  call.cancel();
                }
              });
            }
          }
        });

    call.enqueue(
        new okhttp3.Callback() {
          @Override
          public void onResponse(Call call, Response response) throws IOException {
            fetchState.responseTime = SystemClock.elapsedRealtime();
            final ResponseBody body = response.body();
            try {
              if (!response.isSuccessful()) {
                handleException(
                    call,
                    new IOException("Unexpected HTTP code " + response),
                    callback);
                return;
              }

              long contentLength = body.contentLength();
              if (contentLength < 0) {
                contentLength = 0;
              }
              callback.onResponse(body.byteStream(), (int) contentLength);
            } catch (Exception e) {
              handleException(call, e, callback);
            } finally {
              try {
                body.close();
              } catch (Exception e) {
                FLog.w(TAG, "Exception when closing response body", e);
              }
            }
          }

          @Override
          public void onFailure(Call call, IOException e) {
            handleException(call, e, callback);
          }
        });
  }

  /**
   * Handles exceptions.
   *
   * <p> OkHttp notifies callers of cancellations via an IOException. If IOException is caught
   * after request cancellation, then the exception is interpreted as successful cancellation
   * and onCancellation is called. Otherwise onFailure is called.
   */
  private void handleException(final Call call, final Exception e, final Callback callback) {
    if (call.isCanceled()) {
      callback.onCancellation();
    } else {
      callback.onFailure(e);
    }
  }
}