OkHttpDownloader.java

/*
 * Copyright (C) 2013 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 com.squareup.picasso;

import android.content.Context;
import android.net.Uri;
import com.squareup.okhttp.HttpResponseCache;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.OkResponseCache;

import java.io.File;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

import static com.squareup.picasso.Utils.parseResponseSourceHeader;

/** A {@link Downloader} which uses OkHttp to download images. */
public class OkHttpDownloader implements Downloader {
	static final String RESPONSE_SOURCE_ANDROID = "X-Android-Response-Source";
	static final String RESPONSE_SOURCE_OKHTTP = "OkHttp-Response-Source";

	private final OkHttpClient client;

	private HttpResponseCache cache;

	/**
	 * Create new downloader that uses OkHttp. This will install an image cache
	 * into your application cache directory.
	 */
	public OkHttpDownloader(final Context context) {
		this(Utils.createDefaultCacheDir(context));
	}

	/**
	 * Create new downloader that uses OkHttp. This will install an image cache
	 * into your application cache directory.
	 * 
	 * @param cacheDir
	 *            The directory in which the cache should be stored
	 */
	public OkHttpDownloader(final File cacheDir) {
		this(cacheDir, Utils.calculateDiskCacheSize(cacheDir));
	}

	/**
	 * Create new downloader that uses OkHttp. This will install an image cache
	 * into your application cache directory.
	 * 
	 * @param maxSize
	 *            The size limit for the cache.
	 */
	public OkHttpDownloader(final Context context, final long maxSize) {
		this(Utils.createDefaultCacheDir(context), maxSize);
	}

	/**
	 * Create new downloader that uses OkHttp. This will install an image cache
	 * into your application cache directory.
	 * 
	 * @param cacheDir
	 *            The directory in which the cache should be stored
	 * @param maxSize
	 *            The size limit for the cache.
	 */
	public OkHttpDownloader(final File cacheDir, final long maxSize) {
		this(new OkHttpClient());
		try {
			cache = new HttpResponseCache(cacheDir, maxSize);
			client.setResponseCache(cache);
		} catch (IOException ignored) {
		}
	}

	/**
	 * Create a new downloader that uses the specified OkHttp instance. A
	 * response cache will not be automatically configured.
	 */
	public OkHttpDownloader(OkHttpClient client) {
		this.client = client;
	}

	/**
	 * add by dolphinwang 2014/02/08 用来获取cache对象以便在setting中清除cache数据
	 * 
	 * @return Object of {@link HttpResponseCache} which implements
	 *         {@link OkResponseCache}
	 */
	public HttpResponseCache getResponseCache() {
		if (cache == null) {
			return null;
		}

		return cache;
	}

	protected HttpURLConnection openConnection(Uri uri) throws IOException {
		HttpURLConnection connection = client.open(new URL(uri.toString()));
		connection.setConnectTimeout(Utils.DEFAULT_CONNECT_TIMEOUT);
		connection.setReadTimeout(Utils.DEFAULT_READ_TIMEOUT);
		return connection;
	}

	protected OkHttpClient getClient() {
		return client;
	}

	@Override
	public Response load(Uri uri, boolean localCacheOnly) throws IOException {
		HttpURLConnection connection = openConnection(uri);
		connection.setUseCaches(true);
		if (localCacheOnly) {
			connection.setRequestProperty("Cache-Control",
					"only-if-cached,max-age=" + Integer.MAX_VALUE);
		}

		int responseCode = connection.getResponseCode();
		if (responseCode >= 300) {
			connection.disconnect();
			throw new ResponseException(responseCode + " "
					+ connection.getResponseMessage());
		}

		String responseSource = connection
				.getHeaderField(RESPONSE_SOURCE_OKHTTP);
		if (responseSource == null) {
			responseSource = connection.getHeaderField(RESPONSE_SOURCE_ANDROID);
		}

		long contentLength = connection.getHeaderFieldInt("Content-Length", 0);
		boolean fromCache = parseResponseSourceHeader(responseSource);

		return new Response(connection.getInputStream(), fromCache,
				contentLength);
	}
}