分片上传
本文主要介绍如何使用分片上传。
分片上传(Multipart Upload)分为以下三个步骤:
- 初始化一个分片上传事件。
调用 InitiateMultipartUpload 方法返回 OSS 创建的全局唯一的 uploadId。
- 上传分片。
调用 UploadPart 方法上传分片数据。
说明- 对于同一个uploadId,分片号(partNumber)标识了该分片在整个文件内的相对位置。如果使用同一个分片号上传了新的数据,那么OSS上这个分片已有的数据将会被覆盖。
- OSS将收到的分片数据的MD5值放在ETag头内返回给用户。
- OSS计算上传数据的MD5值,并与SDK计算的MD5值比较,如果不一致则返回InvalidDigest错误码。
- 完成分片上传。
所有分片上传完成后,调用 CompleteMultipartUpload 方法将所有分片合并成完整的文件。
以下通过一个完整的示例对分片上传的流程进行逐步解析:
#include <alibabacloud/oss/OssClient.h>
int64_t getFileSize(const std::string& file)
{
std::fstream f(file, std::ios::in | std::ios::binary);
f.seekg(0, f.end);
int64_t size = f.tellg();
f.close();
return size;
}
using namespace AlibabaCloud::OSS;
int main(void)
{
/* 初始化OSS账号信息 */
std::string AccessKeyId = "yourAccessKeyId";
std::string AccessKeySecret = "yourAccessKeySecret";
std::string Endpoint = "yourEndpoint";
std::string BucketName = "yourBucketName";
std::string ObjectName = "yourObjectName";
/* 初始化网络等资源 */
InitializeSdk();
ClientConfiguration conf;
OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);
InitiateMultipartUploadRequest initUploadRequest(BucketName, ObjectName);
/*(可选)请参见如下示例设置存储类型 */
//initUploadRequest.MetaData().addHeader("x-oss-storage-class", "Standard");
/* 初始化分片上传事件 */
auto uploadIdResult = client.InitiateMultipartUpload(initUploadRequest);
auto uploadId = uploadIdResult.result().UploadId();
std::string fileToUpload = "yourLocalFilename";
int64_t partSize = 100 * 1024;
PartList partETagList;
auto fileSize = getFileSize(fileToUpload);
int partCount = static_cast<int>(fileSize / partSize);
/* 计算分片个数*/
if (fileSize % partSize != 0) {
partCount++;
}
/* 对每一个分片进行上传 */
for (int i = 1; i <= partCount; i++) {
auto skipBytes = partSize * (i - 1);
auto size = (partSize < fileSize - skipBytes) ? partSize : (fileSize - skipBytes);
std::shared_ptr<std::iostream> content = std::make_shared<std::fstream>(fileToUpload, std::ios::in|std::ios::binary);
content->seekg(skipBytes, std::ios::beg);
UploadPartRequest uploadPartRequest(BucketName, ObjectName, content);
uploadPartRequest.setContentLength(size);
uploadPartRequest.setUploadId(uploadId);
uploadPartRequest.setPartNumber(i);
auto uploadPartOutcome = client.UploadPart(uploadPartRequest);
if (uploadPartOutcome.isSuccess()) {
Part part(i, uploadPartOutcome.result().ETag());
partETagList.push_back(part);
}
else {
std::cout << "uploadPart fail" <<
",code:" << uploadPartOutcome.error().Code() <<
",message:" << uploadPartOutcome.error().Message() <<
",requestId:" << uploadPartOutcome.error().RequestId() << std::endl;
}
}
/* 完成分片上传 */
CompleteMultipartUploadRequest request(BucketName, ObjectName);
request.setUploadId(uploadId);
request.setPartList(partETagList);
/*(可选)请参见如下示例设置访问权限ACL */
//request.setAcl(CannedAccessControlList::Private);
auto outcome = client.CompleteMultipartUpload(request);
if (!outcome.isSuccess()) {
/* 异常处理 */
std::cout << "CompleteMultipartUpload fail" <<
",code:" << outcome.error().Code() <<
",message:" << outcome.error().Message() <<
",requestId:" << outcome.error().RequestId() << std::endl;
ShutdownSdk();
return -1;
}
/* 释放网络等资源 */
ShutdownSdk();
return 0;
}
说明 获取已经上传的分片,调用CompleteMultipartUpload接口时需要每个分片的 ETag 值。
ETag 值的获取有两种途径:
- 第一种是上传每个分片的时候,返回结果里面会包含这个分片的 ETag 值,可以保存使用。
- 第二种是通过调用 ListParts 接口获取已经上传的分片的 ETag 值。上述示例采用的是第一种方式。
列举已上传的分片
调用 ListParts 方法列举出指定 UploadID 下所有已上传成功的分片。
- 列举所有已上传的分片
说明 默认情况下,ListParts 只能一次列举 1000 个分片。当分片数量大于 1000 时,请使用分页列举所有已上传分片。以下代码用于列举所有已上传的分片:
#include <alibabacloud/oss/OssClient.h> using namespace AlibabaCloud::OSS; int main(void) { /* 初始化OSS账号信息 */ std::string AccessKeyId = "yourAccessKeyId"; std::string AccessKeySecret = "yourAccessKeySecret"; std::string Endpoint = "yourEndpoint"; std::string BucketName = "yourBucketName"; std::string ObjectName = "yourObjectName"; /* 初始化网络等资源 */ InitializeSdk(); ClientConfiguration conf; OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf); /* 列举已上传分片,默认列举1000个分片 */ ListPartsRequest listuploadrequest(BucketName, ObjectName); listuploadrequest.setUploadId(uploadId); do { auto listuploadresult = client.ListParts(listuploadrequest); if (!listUploadResult.isSuccess()) { /* 异常处理 */ std::cout << "ListParts fail" << ",code:" << listuploadresult.error().Code() << ",message:" << listuploadresult.error().Message() << ",requestId:" << listuploadresult.error().RequestId() << std::endl; break; } else { for (const auto& part : listuploadresult.result().PartList()) { std::cout << "part"<< ",name:" << part.PartNumber() << ",size:" << part.Size() << ",etag:" << part.ETag() << ",lastmodify time:" << part.LastModified() << std::endl; } } listuploadrequest.setPartNumberMarker(listuploadresult.result().NextPartNumberMarker()); } while (listuploadresult.result().IsTruncated()); /* 释放网络等资源 */ ShutdownSdk(); return 0; }
- 分页列举所有已上传的分片
以下代码用于指定每页分片的数量,分页列举所有分片:
#include <alibabacloud/oss/OssClient.h> using namespace AlibabaCloud::OSS; int main(void) { /* 初始化OSS账号信息 */ std::string AccessKeyId = "yourAccessKeyId"; std::string AccessKeySecret = "yourAccessKeySecret"; std::string Endpoint = "yourEndpoint"; std::string BucketName = "yourBucketName"; std::string ObjectName = "yourObjectName"; /* 初始化网络等资源 */ InitializeSdk(); ClientConfiguration conf; OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf); /* 分页列举全部上传的分片 */ /* 设置每页列举最大上传分片数目 */ ListPartsRequest listuploadrequest(BucketName, ObjectName); listuploadrequest.setMaxParts(50); listuploadrequest.setUploadId(uploadId); do { listuploadresult = client.ListParts(listuploadrequest); if (!listUploadResult.isSuccess()) { /* 异常处理 */ std::cout << "ListParts fail" << ",code:" << listuploadresult.error().Code() << ",message:" << listuploadresult.error().Message() << ",requestId:" << listuploadresult.error().RequestId() << std::endl; break; } else { for (const auto& part : listuploadresult.result().PartList()) { std::cout << "part"<< ",name:" << part.PartNumber() << ",size:" << part.Size() << ",etag:" << part.ETag() << ",lastmodify time:" << part.LastModified() << std::endl; } } listuploadrequest.setPartNumberMarker(listuploadresult.result().NextPartNumberMarker()); } while (listuploadresult.result().IsTruncated()); /* 释放网络等资源 */ ShutdownSdk(); return 0; }
列举分片上传事件
调用 ListMultipartUploads 方法列举出所有执行中的分片上传事件,即已初始化但尚未完成或已取消的分片上传事件。
- 列举全部分片上传事件
说明 默认情况下,ListMultipartUploads 只能一次列举 1000 个分片上传事件。当分片数量大于 1000 时,请使用以下分页列举所有上传事件。
以下代码用于列举所有已上传事件:
#include <alibabacloud/oss/OssClient.h> using namespace AlibabaCloud::OSS; int main(void) { /* 初始化OSS账号信息 */ std::string AccessKeyId = "yourAccessKeyId"; std::string AccessKeySecret = "yourAccessKeySecret"; std::string Endpoint = "yourEndpoint"; std::string BucketName = "yourBucketName"; /* 初始化网络等资源 */ InitializeSdk(); ClientConfiguration conf; OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf); /* 列举已上传事件,默认列举1000个分片 */ ListMultipartUploadsRequest listmultiuploadrequest(BucketName); do { auto listresult = client.ListMultipartUploads(listmultiuploadrequest); if (!listresult.isSuccess()) { /* 异常处理 */ std::cout << "ListMultipartUploads fail" << ",code:" << listresult.error().Code() << ",message:" << listresult.error().Message() << ",requestId:" << listresult.error().RequestId() << std::endl; break; } else { for (const auto& part : listresult.result().MultipartUploadList()) { std::cout << "part"<< ",name:" << part.Key << ",uploadid:" << part.UploadId << ",initiated time:" << part.Initiated << std::endl; } } listmultiuploadrequest.setKeyMarker(listresult.result().NextKeyMarker()); listmultiuploadrequest.setUploadIdMarker(listresult.result().NextUploadIdMarker()); } while (listresult.result().IsTruncated()); /* 释放网络等资源 */ ShutdownSdk(); return 0; }
- 分页列举所有上传事件
以下代码用于分页列举所有上传事件:
#include <alibabacloud/oss/OssClient.h> using namespace AlibabaCloud::OSS; int main(void) { /* 初始化OSS账号信息 */ std::string AccessKeyId = "yourAccessKeyId"; std::string AccessKeySecret = "yourAccessKeySecret"; std::string Endpoint = "yourEndpoint"; std::string BucketName = "yourBucketName"; /* 初始化网络等资源 */ InitializeSdk(); ClientConfiguration conf; OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf); /* 分页列举全部上传事件 */ /* 设置每页列举最大上传事件数目 */ ListMultipartUploadsRequest listmultiuploadrequest(BucketName); listmultiuploadrequest.setMaxUploads(50); do { listresult = client.ListMultipartUploads(listmultiuploadrequest); if (!listresult.isSuccess()) { /* 异常处理 */ std::cout << "ListMultipartUploads fail" << ",code:" << listresult.error().Code() << ",message:" << listresult.error().Message() << ",requestId:" << listresult.error().RequestId() << std::endl; break; } else { for (const auto& part : listresult.result().MultipartUploadList()) { std::cout << "part"<< ",name:" << part.Key << ",uploadid:" << part.UploadId << ",initiated time:" << part.Initiated << std::endl; } } listmultiuploadrequest.setKeyMarker(listresult.result().NextKeyMarker()); listmultiuploadrequest.setUploadIdMarker(listresult.result().NextUploadIdMarker()); } while (listresult.result().IsTruncated()); /* 释放网络等资源 */ ShutdownSdk(); return 0; }
取消分片上传事件
以下代码用于取消分片上传事件:
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;
int main(void)
{
/* 初始化OSS账号信息 */
std::string AccessKeyId = "yourAccessKeyId";
std::string AccessKeySecret = "yourAccessKeySecret";
std::string Endpoint = "yourEndpoint";
std::string BucketName = "yourBucketName";
std::string ObjectName = "yourObjectName";
/* 初始化网络等资源 */
InitializeSdk();
ClientConfiguration conf;
OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);
InitiateMultipartUploadRequest initUploadRequest(BucketName, ObjectName);
/* 初始化分片上传事件 */
auto uploadIdResult = client.InitiateMultipartUpload(initUploadRequest);
auto uploadId = uploadIdResult.result().UploadId();
/* 取消分片上传 */
AbortMultipartUploadRequest abortUploadRequest(BucketName, key, uploadId);
auto abortUploadIdResult = client.AbortMultipartUpload(abortUploadRequest);
if (!abortUploadIdResult.isSuccess()) {
/* 异常处理 */
std::cout << "AbortMultipartUpload fail" <<
",code:" << outcome.error().Code() <<
",message:" << outcome.error().Message() <<
",requestId:" << outcome.error().RequestId() << std::endl;
ShutdownSdk();
return -1;
}
/* 释放网络等资源 */
ShutdownSdk();
return 0;
}
说明 当一个分片上传事件被取消后,就不能再使用 upload_id 做任何操作,已经上传的分片数据也会被删除。
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