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背景

本文主要介绍基于腾讯云对象存储(Cloud Object Storage,COS)服务,移动端在弱网情况下,如何根据实际情况动态调节上传分块大小,来提高上传成功率。
注意:
该功能目前处于灰度测试阶段,如需支持该功能,请 联系我们

实践须知

1. COS 目前支持最小分块大小为100KB。
2. 分块越小,意味着请求数也多。目前根据测试统计,100KB分块大小的请求耗时是1MB分块大小的2倍左右。
3. 在正常网络下发起请求,建议设置分块大小为1MB及以上。
4. 在网络信号弱等网络环境下上传对象容易导致上传失败,可以考虑将分块大小设置为100KB,再重新上传。
5. 分块大小设置越小,将来下载该文件时可能比较缓慢。

示例

Android SDK

下面举例在弱网络环境中,使用分块上传对象的示例代码:
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import com.tencent.cos.xml.CosXmlService;
import com.tencent.cos.xml.CosXmlServiceConfig;
import com.tencent.cos.xml.common.ClientErrorCode;
import com.tencent.cos.xml.common.Region;
import com.tencent.cos.xml.exception.CosXmlClientException;
import com.tencent.cos.xml.exception.CosXmlServiceException;
import com.tencent.cos.xml.listener.CosXmlProgressListener;
import com.tencent.cos.xml.listener.CosXmlResultListener;
import com.tencent.cos.xml.model.CosXmlRequest;
import com.tencent.cos.xml.model.CosXmlResult;
import com.tencent.cos.xml.transfer.COSXMLUploadTask;
import com.tencent.cos.xml.transfer.TransferConfig;
import com.tencent.cos.xml.transfer.TransferManager;
import com.tencent.cos.xml.transfer.TransferState;
import com.tencent.cos.xml.transfer.TransferStateListener;
import com.tencent.qcloud.core.auth.QCloudCredentialProvider;
import com.tencent.qcloud.core.auth.ShortTimeCredentialProvider;

public class ResumeHelper {
private final static String TAG = ResumeHelper.class.getSimpleName();

private Context context;
String bucket = "examplebucket-1250000000"; //存储桶,格式 BucketName-APPID, 替换为您的 bucket
String region = Region.AP_Guangzhou.getRegion(); //存储桶所在地域, 填写您的 bucket 所在的地域
private CosXmlService cosXmlService;

private Handler mainHandler;
private boolean isTriedOnce = false; //是否已重传过,避免无限制重传
private final int MESSAGE_RETRY = 1;

public ResumeHelper(Context context){
this.context = context;
this.mainHandler = new Handler(context.getMainLooper()){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case MESSAGE_RETRY:
/** 已重传过 */
if(isTriedOnce)return;
isTriedOnce = true;
Parameter parameter = (Parameter) msg.obj;
/** 再次上传 */
upload(parameter.srcPath, parameter.cosPath, parameter.uploadId, parameter.sliceSize);
break;
}
}
};
initCosXml();
}

/**
* 初始化 CosXmlService
*/
private void initCosXml(){
/** 初始化 CosXmlServiceConfig */
CosXmlServiceConfig cosXmlServiceConfig = new CosXmlServiceConfig.Builder()
.setDebuggable(true)
.isHttps(true)
.setRegion(region)
.builder();

//此处为了方便测试,使用了永久密钥,实际应用中建议使用临时密钥
String secretId = "COS_SECRETID"; //填写您的 云 API 密钥 SecretId
String secretKey = "COS_SECRETKEY"; //填写您的 云 API 密钥 SecretKey
/** 初始化 密钥信息 */
QCloudCredentialProvider qCloudCredentialProvider = new ShortTimeCredentialProvider(secretId, secretKey, 6000);

/** 初始化 CosXmlService */
cosXmlService = new CosXmlService(context, cosXmlServiceConfig, qCloudCredentialProvider);
}

/**
* 上传
* @param srcPath 本地文件路径
* @param cosPath 存储在 COS 上的路径
* @param uploadId 是否续传,若无,则为 null
* @param sliceSize 分块上传时,设置的分块块大小
*/
public void upload(final String srcPath, final String cosPath, final String uploadId, long sliceSize){

/** 设置分块上传时,分块块的大小 */
TransferConfig transferConfig = new TransferConfig.Builder()
.setSliceSizeForUpload(sliceSize)
.build();
/** 初始化TransferManager */
TransferManager transferManager = new TransferManager(cosXmlService, transferConfig);
/** 开始上传: 若 uploadId != null,则可以进行续传 */
final COSXMLUploadTask uploadTask = transferManager.upload(bucket, cosPath, srcPath, uploadId);
/** 显示任务状态信息 */
uploadTask.setTransferStateListener(new TransferStateListener() {
@Override
public void onStateChanged(TransferState state) {
Log.d(TAG, "upload task state: " + state.name());
}
});
/** 显示任务上传进度 */
uploadTask.setCosXmlProgressListener(new CosXmlProgressListener() {
@Override
public void onProgress(long complete, long target) {
Log.d(TAG, "upload task progress: " + complete + "/" + target);
}
});
/** 显示任务上传结果 */
uploadTask.setCosXmlResultListener(new CosXmlResultListener() {
/** 任务上传成功 */
@Override
public void onSuccess(CosXmlRequest request, CosXmlResult result) {
COSXMLUploadTask.COSXMLUploadTaskResult uploadTaskResult = (COSXMLUploadTask.COSXMLUploadTaskResult) result;
Log.d(TAG, "upload task success: " + uploadTaskResult.printResult());
}

/** 任务上传失败 */
@Override
public void onFail(CosXmlRequest request, CosXmlClientException exception, CosXmlServiceException serviceException) {
Log.d(TAG, "upload task failed: " + (exception == null ? serviceException.getMessage() :
(exception.errorCode + "," + exception.getMessage())));
if(exception != null){
/** 若是因为网络导致失败, 则可尝试将分块大小设置为100KB再运行一遍*/
if(exception.errorCode == ClientErrorCode.IO_ERROR.getCode()
|| exception.errorCode == ClientErrorCode.POOR_NETWORK.getCode()){
Log.d(TAG, "upload task try again");
Message msg = mainHandler.obtainMessage();
msg.what = MESSAGE_RETRY;
Parameter parameter = new Parameter();
parameter.cosPath = cosPath;
parameter.srcPath = srcPath;
parameter.uploadId = uploadTask.getUploadId();
parameter.sliceSize = 100 * 1024L;
msg.obj = parameter;
mainHandler.sendMessage(msg);
}
}
}
});
}

private static class Parameter{
private String cosPath;
private String srcPath;
private String uploadId;
private long sliceSize;
}
}

iOS SDK

下面举例在弱网络环境中,使用分块上传对象的示例代码:
QCloudCOSXMLUploadObjectRequest* put = [QCloudCOSXMLUploadObjectRequest new];
NSURL* url = [NSURL fileURLWithPath:@"filePathURL"];
put.object = @"text.txt";
put.bucket = self.bucket;
put.body = url;
[put setSendProcessBlock:^(int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend) {
NSLog(@"upload %lld totalSend %lld aim %lld", bytesSent, totalBytesSent, totalBytesExpectedToSend);
}];
[put setFinishBlock:^(QCloudUploadObjectResult *result, NSError *error) {
/**
1. 如果是请求超时,则可能是网络过慢导致的,可以从 error 中得到续传相关的信息 resumeData(存储在 QCloudUploadResumeDataKey 字段中)
2. 调用 QCloudCOSXMLUploadObjectRequest的requestWithRequestData 传入 resumeData,重新生成一个 request。
2. 根据需要通过 QCloudCOSXMLUploadObjectRequest 的 sliceSize 重新设置分块大小
3. 开始上传
*/
if (error.code == -1001) {
NSData *resumeData =error.userInfo[QCloudUploadResumeDataKey];
if (resumeData) {
QCloudCOSXMLUploadObjectRequest* request = [QCloudCOSXMLUploadObjectRequest requestWithRequestData:resumeData];
request.sliceSize = 100*1024;
[request setFinishBlock:^(QCloudUploadObjectResult* outputObject, NSError *error) {
NSLog(@"result: %@",outputObject);
}];

[request setSendProcessBlock:^(int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend) {
NSLog(@"upload %lld totalSend %lld aim %lld", bytesSent, totalBytesSent, totalBytesExpectedToSend);
}];
[[QCloudCOSTransferMangerService defaultCOSTransferManager] UploadObject:request];
}
}
}];
[[QCloudCOSTransferMangerService defaultCOSTransferManager] UploadObject:put];