腾讯云对象存储下载对象

简介

本文档提供关于下载对象的 API 概览以及 SDK 示例代码。

SDK API 参考

SDK 所有接口的具体参数与方法说明，请参考 SDK API。

高级接口（推荐）

下载对象（断点续传）

高级接口支持暂停、恢复以及取消下载请求，同时支持断点下载功能。说明.NET Framework 4.0 及以下的用户，高级接口暂不可用，详见 向下兼容指南。高级下载接口从 5.4.26 版本开始支持并发分块下载，下载新版 SDK 前往 Releases 或参见 快速入门。

示例代码一: 下载对象

//: # “.cssg-snippet-transfer-download-object”

using COSXML.Model.Object;using COSXML.Auth;using COSXML.Transfer;using System;using COSXML;using System.Threading.Tasks;
namespace COSSnippet{    public class TransferDownloadObjectModel {
      private CosXml cosXml;
      TransferDownloadObjectModel() {        CosXmlConfig config = new CosXmlConfig.Builder()          .SetRegion("COS_REGION") // 设置默认的地域, COS 地域的简称请参照 https://cloud.tencent.com/document/product/436/6224          .Build();
        string secretId = "SECRET_ID";   // 云 API 密钥 SecretId, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi        string secretKey = "SECRET_KEY"; // 云 API 密钥 SecretKey, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi        long durationSecond = 600;          //每次请求签名有效时长，单位为秒        QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId,           secretKey, durationSecond);
        this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);      }
      /// 高级接口下载对象      public async Task TransferDownloadObject()      {        // 初始化 TransferConfig        TransferConfig transferConfig = new TransferConfig();        // 手动设置高级下载接口的分块阈值为 20MB(默认为20MB), 从5.4.26版本开始支持！        //transferConfig.DivisionForDownload = 20 * 1024 * 1024;        // 手动设置高级下载接口的分块大小为 10MB(默认为5MB),不建议此处设置过小的分块值,可能导致频繁重试或下载速度不合预期        //transferConfig.SliceSizeForDownload = 10 * 1024 * 1024;
        // 初始化 TransferManager        TransferManager transferManager = new TransferManager(cosXml, transferConfig);
        String bucket = "examplebucket-1250000000"; //存储桶，格式：BucketName-APPID        String cosPath = "exampleobject"; //对象在存储桶中的位置标识符，即称对象键        string localDir = System.IO.Path.GetTempPath();//本地文件夹        string localFileName = "my-local-temp-file"; //指定本地保存的文件名
        // 下载对象        COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(bucket, cosPath,           localDir, localFileName);
        // 手动设置高级下载接口的并发数 (默认为5), 从5.4.26版本开始支持！        //downloadTask.SetMaxTasks(10);        downloadTask.progressCallback = delegate (long completed, long total)        {            Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));        };
        try {          COSXML.Transfer.COSXMLDownloadTask.DownloadTaskResult result = await             transferManager.DownloadAsync(downloadTask);          Console.WriteLine(result.GetResultInfo());          string eTag = result.eTag;        }        catch (COSXML.CosException.CosClientException clientEx)        {          //请求失败          Console.WriteLine("CosClientException: " + clientEx);        }        catch (COSXML.CosException.CosServerException serverEx)        {          //请求失败          Console.WriteLine("CosServerException: " + serverEx.GetInfo());        }      }

      static void Main(string[] args)      {        TransferDownloadObjectModel m = new TransferDownloadObjectModel();
        /// 高级接口下载对象        m.TransferDownloadObject().Wait();      }    }}

说明 更多完整示例，请前往 GitHub 查看。

示例代码二: 设置下载支持断点续传

//: # “.cssg-snippet-transfer-download-resumable”

COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(request); //开启断点续传，当本地存在未下载完成文件时，追加下载到文件末尾 //本地文件已存在部分不符合本次下载的内容，可能导致下载失败，请删除文件重试 downloadTask.SetResumableDownload(true); try {   COSXML.Transfer.COSXMLDownloadTask.DownloadTaskResult result = await    transferManager.DownloadAsync(downloadTask);   Console.WriteLine(result.GetResultInfo());   string eTag = result.eTag; } catch (Exception e) {   Console.WriteLine("CosException: " + e); }

说明 更多完整示例，请前往 GitHub 查看。

示例代码三: 批量下载

//: # “.cssg-snippet-transfer-batch-download-objects”

TransferConfig transferConfig = new TransferConfig();
// 初始化 TransferManagerTransferManager transferManager = new TransferManager(cosXml, transferConfig);
// 存储桶名称，此处填入格式必须为 bucketname-APPID, 其中 APPID 获取参考 https://console.cloud.tencent.com/developerstring bucket = "examplebucket-1250000000";string localDir = System.IO.Path.GetTempPath();//本地文件夹
for (int i = 0; i < 5; i++) {  // 下载对象  string cosPath = "exampleobject" + i; //对象在存储桶中的位置标识符，即称对象键  string localFileName = "my-local-temp-file"; //指定本地保存的文件名  COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(bucket, cosPath,     localDir, localFileName);  await transferManager.DownloadAsync(downloadTask);}

说明 更多完整示例，请前往 GitHub 查看。

示例代码四：单链接限速下载

//: # “.cssg-snippet-transfer-download-objects-with-speed-limit”

TransferConfig transferConfig = new TransferConfig();
// 初始化 TransferManagerTransferManager transferManager = new TransferManager(cosXml, transferConfig);
String bucket = "examplebucket-1250000000"; //存储桶，格式：BucketName-APPIDString cosPath = "exampleobject"; //对象在存储桶中的位置标识符，即称对象键string localDir = System.IO.Path.GetTempPath();//本地文件夹string localFileName = "my-local-temp-file"; //指定本地保存的文件名
GetObjectRequest request = new GetObjectRequest(bucket,         cosPath, localDir, localFileName);request.LimitTraffic(8 * 1000 * 1024); // 限制为1MB/s
COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(request);await transferManager.DownloadAsync(downloadTask);

说明 更多完整示例，请前往 GitHub 查看。

示例代码五：文件夹下载

//: # “.cssg-snippet-transfer-download-objects-from-folder”

using COSXML.Common;using COSXML.CosException;using COSXML.Model;using COSXML.Model.Object;using COSXML.Model.Tag;using COSXML.Model.Bucket;using COSXML.Model.Service;using COSXML.Utils;using COSXML.Auth;using COSXML.Transfer;using System;using COSXML;using System.Collections.Generic;using System.IO;using System.Linq;using System.Reflection;using System.Text;using System.Threading;using System.Threading.Tasks;
namespace COSSnippet{  public class TransferDownloadObjectModel {
    private CosXml cosXml;    private string nextMarker;
    TransferDownloadObjectModel() {      CosXmlConfig config = new CosXmlConfig.Builder()        .SetRegion("COS_REGION") // 设置默认的地域, COS 地域的简称请参照 https://cloud.tencent.com/document/product/436/6224        .Build();
      string secretId = "SECRET_ID";   // 云 API 密钥 SecretId, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi      string secretKey = "SECRET_KEY"; // 云 API 密钥 SecretKey, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi      long durationSecond = 600; //每次请求签名有效时长，单位为秒      QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId,         secretKey, durationSecond);
      this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);  }
    public void GetObjectsFromFolder()    {    // 注意：COS中实际不存在文件夹下载的接口    // 需要通过组合 “指定前缀列出” 和 “遍历列出的对象key做下载” 两种操作，实现类似文件夹下载的操作    // 下面的操作，把对象列出到列表里，然后异步下载列表中的对象        String nextMarker = null;
        List  downloadList = new List();        string bucket = "examplebucket-1250000000";        string prefix = "folder1/"; //指定前缀        // 循环请求直到没有下一页数据        do        {            // 存储桶名称，此处填入格式必须为 bucketname-APPID, 其中 APPID 获取参考 https://console.cloud.tencent.com/developer            GetBucketRequest listRequest = new GetBucketRequest(bucket);            //获取 folder1/ 下的所有对象以及子目录            listRequest.SetPrefix(prefix);            listRequest.SetMarker(nextMarker);            //执行列出对象请求            GetBucketResult listResult = cosXml.GetBucket(listRequest);            ListBucket info = listResult.listBucket;            // 对象列表            List objects = info.contentsList;            // 下一页的下标            nextMarker = info.nextMarker;
            //对象列表            foreach (var content in objects)            {            downloadList.Add(content.key);            Console.WriteLine("adding key:" + content.key);            }      } while (nextMarker != null);        Console.WriteLine("download list construct done, " + downloadList.Count + " objects added");
        TransferConfig transferConfig = new TransferConfig();        TransferManager transferManager = new TransferManager(cosXml, transferConfig);        string localDir = System.IO.Path.GetTempPath();//本地文件夹
        List taskList = new List();        for (int i = 0; i < downloadList.Count; i++)        {            // 遍历待下载列表，下载内容写到 filename_i 文件中            COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(bucket, downloadList[i],                 localDir, "filename_" + i.ToString());            // 异步下载, 加入task队列            Task task = transferManager.DownloadAsync(downloadTask);            taskList.Add(task);         }        Console.WriteLine("download tasks submitted, total " + taskList.Count + " tasks added");
        //等待TaskList中所有Task结束        foreach(Task task in taskList)        {            task.Wait();            Console.WriteLine("download completed");        }  }
      static void Main(string[] args)      {        TransferDownloadObjectModel m = new TransferDownloadObjectModel();        /// 批量下载文件夹中文件        m.GetObjectsFromFolder();      }    }}

说明 更多完整示例，请前往 GitHub 查看。

示例代码六: 下载暂停、继续与取消

对于下载任务，可以通过以下方式暂停：

downloadTask.Pause();

暂停之后，可以通过以下方式续传：

downloadTask.Resume();

也通过以下方式取消上传：

downloadTask.Cancel();

说明 更多完整示例，请前往 GitHub 查看。

简单操作

下载对象

功能说明

下载一个 Object（文件/对象）至本地（GET Object）。

示例代码一：单对象简单下载

using COSXML.Model.Object;using COSXML.Auth;using System;using COSXML;
namespace COSSnippet{    public class GetObjectModel {
      private CosXml cosXml;
      GetObjectModel() {        CosXmlConfig config = new CosXmlConfig.Builder()          .SetRegion("COS_REGION") // 设置默认的地域, COS 地域的简称请参照 https://cloud.tencent.com/document/product/436/6224           .Build();
        string secretId = "SECRET_ID";   // 云 API 密钥 SecretId, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi        string secretKey = "SECRET_KEY"; // 云 API 密钥 SecretKey, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi        long durationSecond = 600;          //每次请求签名有效时长，单位为秒        QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId,           secretKey, durationSecond);
        this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);      }
      /// 下载对象      public void GetObject()      {        //.cssg-snippet-body-start:[get-object]        try        {          // 存储桶名称，此处填入格式必须为 bucketname-APPID, 其中 APPID 获取参考 https://console.cloud.tencent.com/developer          string bucket = "examplebucket-1250000000";          string key = "exampleobject"; //对象键          string localDir = System.IO.Path.GetTempPath();//本地文件夹          string localFileName = "my-local-temp-file"; //指定本地保存的文件名          GetObjectRequest request = new GetObjectRequest(bucket, key, localDir, localFileName);          //设置进度回调          request.SetCosProgressCallback(delegate (long completed, long total)          {            Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));          });          //执行请求          GetObjectResult result = cosXml.GetObject(request);          //请求成功          Console.WriteLine(result.GetResultInfo());        }        catch (COSXML.CosException.CosClientException clientEx)        {          //请求失败          Console.WriteLine("CosClientException: " + clientEx);        }        catch (COSXML.CosException.CosServerException serverEx)        {          //请求失败          Console.WriteLine("CosServerException: " + serverEx.GetInfo());        }      }
      static void Main(string[] args)      {        GetObjectModel m = new GetObjectModel();        /// 下载对象        m.GetObject();      }    }}

说明 更多完整示例，请前往 GitHub 查看。

示例代码二：下载对象到内存中

using COSXML.Model.Object;using COSXML.Auth;using System;using COSXML;
namespace COSSnippet{    public class GetObjectModel {
      private CosXml cosXml;
      GetObjectModel() {        CosXmlConfig config = new CosXmlConfig.Builder()          .SetRegion("COS_REGION") // 设置默认的地域, COS 地域的简称请参照 https://cloud.tencent.com/document/product/436/6224           .Build();
        string secretId = "SECRET_ID";   // 云 API 密钥 SecretId, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi        string secretKey = "SECRET_KEY"; // 云 API 密钥 SecretKey, 获取 API 密钥请参照 https://console.cloud.tencent.com/cam/capi        long durationSecond = 600;          //每次请求签名有效时长，单位为秒        QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId,           secretKey, durationSecond);
        this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);      }
      /// 下载返回 bytes 数据      public void downloadToMem() {        try        {          // 存储桶名称，此处填入格式必须为 bucketname-APPID, 其中 APPID 获取参考 https://console.cloud.tencent.com/developer          string bucket = "examplebucket-1250000000";          string key = "exampleobject"; //对象键
          GetObjectBytesRequest request = new GetObjectBytesRequest(bucket, key);          //设置进度回调          request.SetCosProgressCallback(delegate (long completed, long total)          {            Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));          });          //执行请求          GetObjectBytesResult result = cosXml.GetObject(request);          //获取内容到 byte 数组中          byte[] content = result.content;          //请求成功          Console.WriteLine(result.GetResultInfo());        }        catch (COSXML.CosException.CosClientException clientEx)        {          //请求失败          Console.WriteLine("CosClientException: " + clientEx);        }        catch (COSXML.CosException.CosServerException serverEx)        {          //请求失败          Console.WriteLine("CosServerException: " + serverEx.GetInfo());        }      }
      // .cssg-methods-pragma
      static void Main(string[] args)      {        GetObjectModel m = new GetObjectModel();
        /// 下载对象到内存中        m.downloadToMem();        // .cssg-methods-pragma      }    }}

说明 更多完整示例，请前往 GitHub 查看。
对象存储官网1折活动，限时活动，即将结束，速速收藏
同尘科技为腾讯云授权服务中心。
购买腾讯云产品享受折上折，更有现金返利。同意关联立享优惠