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    Object Storage Service：禁止覆蓋同名檔案（C++ SDK）

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    Object Storage Service：禁止覆蓋同名檔案（C++ SDK）

    更新時間：Nov 29, 2025

    預設情況下，如果新添加檔案與現有檔案（Object）同名且對該檔案有存取權限，則新添加的檔案將覆蓋原有的檔案。本文介紹如何通過佈建要求頭x-oss-forbid-overwrite在簡單上傳、拷貝檔案及分區上傳等情境中禁止覆蓋同名檔案。

    注意事項

    • 本文以華東1（杭州）外網Endpoint為例。如果您希望通過與OSS同地區的其他阿里雲產品訪問OSS，請使用內網Endpoint。關於OSS支援的Region與Endpoint的對應關係，請參見地區和Endpoint。

    • 本文以OSS網域名稱建立OSSClient為例。如果您希望通過自訂網域名、STS等方式建立OSSClient，請參見建立OssClient。

    簡單上傳

    以下代碼用於簡單上傳時禁止覆蓋同名檔案：

    #include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* 初始化OSS帳號資訊。*/
            
     /* yourEndpoint填寫Bucket所在地區對應的Endpoint。以華東1（杭州）為例，Endpoint填寫為https://oss-cn-hangzhou.aliyuncs.com。*/
    std::string Endpoint = "yourEndpoint";
    /* yourRegion填寫Bucket所在地區對應的Region。以華東1（杭州）為例，Region填寫為cn-hangzhou。*/
    std::string Region = "yourRegion";
    /* 填寫Bucket名稱，例如examplebucket。*/
    std::string BucketName = "examplebucket";
    /* 填寫Object完整路徑，完整路徑中不能包含Bucket名稱，例如exampledir/exampleobject.txt。*/
    std::string ObjectName = "exampledir/exampleobject.txt";

    /* 初始化網路等資源。*/
    InitializeSdk();

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* 從環境變數中擷取訪問憑證。運行本程式碼範例之前，請確保已設定環境變數OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。*/
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
    client.SetRegion(Region);
    std::shared_ptr<std::iostream> content = std::make_shared<std::stringstream>();
    *content << "test cpp sdk";

    /* 指定上傳檔案操作時是否覆蓋同名Object。*/
    /* 不指定x-oss-forbid-overwrite時，預設覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為false時，表示允許覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為true時，表示禁止覆蓋同名Object，如果同名Object已存在，程式將報錯。*/
    ObjectMetaData meta;
    meta.addHeader("x-oss-forbid-overwrite", "true");

    PutObjectRequest request(BucketName, ObjectName, content, meta);

    /* 上傳檔案。*/
    auto outcome = client.PutObject(request);

    if (!outcome.isSuccess()) {
            /* 異常處理。*/
            std::cout << "PutObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* 釋放網路等資源。*/
    ShutdownSdk();
    return 0;
}

    拷貝檔案

    拷貝小檔案

    以下代碼用於拷貝小檔案時禁止覆蓋同名檔案：

    #include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* 初始化OSS帳號資訊。*/
            
     /* yourEndpoint填寫Bucket所在地區對應的Endpoint。以華東1（杭州）為例，Endpoint填寫為https://oss-cn-hangzhou.aliyuncs.com。*/
    std::string Endpoint = "yourEndpoint";
    /* yourRegion填寫Bucket所在地區對應的Region。以華東1（杭州）為例，Region填寫為cn-hangzhou。*/
    std::string Region = "yourRegion";
    /* 填寫源Bucket名稱，例如srcexamplebucket。*/
    std::string SourceBucketName = "srcexamplebucket";
    /* 填寫與源Bucket處於同一地區的目標Bucket名稱，例如destbucket。*/
    std::string CopyBucketName = "destbucket";
    /* 填寫源Object的完整路徑，完整路徑中不能包含Bucket名稱，例如srcdir/scrobject.txt。*/
    std::string SourceObjectName = "srcdir/scrobject.txt";
    /* 填寫目標Object的完整路徑，完整路徑中不能包含Bucket名稱，例如destdir/destobject.txt。*/
    std::string CopyObjectName = "destdir/destobject.txt";

    /* 初始化網路等資源。*/
    InitializeSdk();

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* 從環境變數中擷取訪問憑證。運行本程式碼範例之前，請確保已設定環境變數OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。*/
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
    client.SetRegion(Region);

    /* 指定上傳檔案操作時是否覆蓋同名Object。*/
    /* 不指定x-oss-forbid-overwrite時，預設覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為false時，表示允許覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為true時，表示禁止覆蓋同名Object，如果同名Object已存在，程式將報錯。*/
    ObjectMetaData meta;
    meta.addHeader("x-oss-forbid-overwrite", "true");

    CopyObjectRequest request(CopyBucketName, CopyObjectName, meta);
    request.setCopySource(SourceBucketName, SourceObjectName);

    /* 拷貝檔案。*/
    auto outcome = client.CopyObject(request);

    if (!outcome.isSuccess()) {
            /* 異常處理。*/
            std::cout << "CopyObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* 釋放網路等資源。*/
    ShutdownSdk();
    return 0;
}

    拷貝大檔案

    以下代碼用於拷貝大檔案時禁止覆蓋同名檔案：

    #include <alibabacloud/oss/OssClient.h>
#include <sstream>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* 初始化OSS帳號資訊。*/
            
     /* yourEndpoint填寫Bucket所在地區對應的Endpoint。以華東1（杭州）為例，Endpoint填寫為https://oss-cn-hangzhou.aliyuncs.com。*/
    std::string Endpoint = "yourEndpoint";
    /* yourRegion填寫Bucket所在地區對應的Region。以華東1（杭州）為例，Region填寫為cn-hangzhou。*/
    std::string Region = "yourRegion";
    /* 填寫源Bucket名稱，例如srcexamplebucket。*/
    std::string SourceBucketName = "srcexamplebucket";
    /* 填寫與源Bucket處於同一地區的目標Bucket名稱，例如destbucket。*/
    std::string CopyBucketName = "destbucket";
    /* 填寫源Object的完整路徑，完整路徑中不能包含Bucket名稱，例如srcdir/scrobject.txt。*/
    std::string SourceObjectName = "srcdir/scrobject.txt";
    /* 填寫目標Object的完整路徑，完整路徑中不能包含Bucket名稱，例如destdir/destobject.txt。*/
    std::string CopyObjectName = "destdir/destobject.txt";

    /* 初始化網路等資源。*/
    InitializeSdk();

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* 從環境變數中擷取訪問憑證。運行本程式碼範例之前，請確保已設定環境變數OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。*/
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
    client.SetRegion(Region);

    auto getObjectMetaReq = GetObjectMetaRequest(SourceBucketName, SourceObjectName);
    auto getObjectMetaResult = GetObjectMeta(getObjectMetaReq);
    if (!getObjectMetaResult.isSuccess()) {
        std::cout << "GetObjectMeta fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }
        /* 擷取被拷貝檔案大小。*/
    auto objectSize = getObjectMetaResult.result().ContentLength();

    /* 拷貝大檔案。*/
    ObjectMetaData metaData;
    std::stringstream ssDesc;
    ssDesc << "/" << SourceBucketName << "/" << SourceObjectName;
    std::string value = ssDesc.str();
    metaData.addHeader("x-oss-copy-source", value);

    /* 指定上傳檔案操作時是否覆蓋同名Object。*/
    /* 不指定x-oss-forbid-overwrite時，預設覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為false時，表示允許覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為true時，表示禁止覆蓋同名Object，如果同名Object已存在，程式將報錯。*/
    metaData.addHeader("x-oss-forbid-overwrite", "true");

    InitiateMultipartUploadRequest initUploadRequest(BucketName, ObjectName, metaData);

    /* 初始化分區拷貝事件。*/
    auto uploadIdResult = client.InitiateMultipartUpload(initUploadRequest);
    auto uploadId = uploadIdResult.result().UploadId();
    int64_t partSize = 100 * 1024;
    PartList partETagList;
    int partCount = static_cast<int>(objectSize / partSize);
    /* 計算分區個數。*/
    if (objectSize % partSize != 0) {
        partCount++;
    }

    /* 對每一個分區進行拷貝。*/
    for (int i = 1; i <= partCount; i++) {
        auto skipBytes = partSize * (i - 1);
        auto size = (partSize < objectSize - skipBytes) ? partSize : (objectSize - skipBytes);
        auto uploadPartCopyReq = UploadPartCopyRequest(CopyBucketName, CopyObjectName, SourceBucketName, SourceObjectName,uploadId, i + 1);
        uploadPartCopyReq.setCopySourceRange(skipBytes, skipBytes + size -1);
        auto uploadPartOutcome = client.UploadPartCopy(uploadPartCopyReq);
        if (uploadPartOutcome.isSuccess()) {
            Part part(i, uploadPartOutcome.result().ETag());
            partETagList.push_back(part);
        }
        else {
            std::cout << "UploadPartCopy fail" <<
            ",code:" << outcome.error().Code() <<
            ",message:" << outcome.error().Message() <<
            ",requestId:" << outcome.error().RequestId() << std::endl;
        }

    }

    /* 完成分區拷貝。*/
    CompleteMultipartUploadRequest request(CopyBucketName, CopyObjectName, partETagList, uploadId);

    /* 指定上傳檔案操作時是否覆蓋同名Object。*/
    /* 不指定x-oss-forbid-overwrite時，預設覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為false時，表示允許覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為true時，表示禁止覆蓋同名Object，如果同名Object已存在，程式將報錯。*/ 
    request.MetaData().addHeader("x-oss-forbid-overwrite", "true");

    auto outcome = client.CompleteMultipartUpload(request);

    if (!outcome.isSuccess()) {
        /* 異常處理。*/
        std::cout << "CompleteMultipartUpload fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* 釋放網路等資源。*/
    ShutdownSdk();
    return 0;
}

    分區上傳

    以下代碼用於分區上傳時禁止覆蓋同名檔案：

    #include <alibabacloud/oss/OssClient.h>
#include <fstream>

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帳號資訊。*/
            
    /* yourEndpoint填寫Bucket所在地區對應的Endpoint。以華東1（杭州）為例，Endpoint填寫為https://oss-cn-hangzhou.aliyuncs.com。*/
    std::string Endpoint = "yourEndpoint";
    /* 填寫Bucket名稱，例如examplebucket。*/
    std::string BucketName = "examplebucket";
    /* 填寫Object完整路徑，完整路徑中不能包含Bucket名稱，例如exampledir/exampleobject.txt。*/
    std::string ObjectName = "exampledir/exampleobject.txt";

    /* 初始化網路等資源。*/
    InitializeSdk();

    ClientConfiguration conf;
    /* 從環境變數中擷取訪問憑證。運行本程式碼範例之前，請確保已設定環境變數OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。*/
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);

    /* 指定上傳檔案操作時是否覆蓋同名Object。*/
    /* 不指定x-oss-forbid-overwrite時，預設覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為false時，表示允許覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為true時，表示禁止覆蓋同名Object，如果同名Object已存在，程式將報錯。*/
    ObjectMetaData meta;
    meta.addHeader("x-oss-forbid-overwrite", "true");

    InitiateMultipartUploadRequest initUploadRequest(BucketName, ObjectName, meta);

    /* 初始化分區上傳事件。*/
    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);
    /* 計算分區個數。*/
    if (fileSize % partSize != 0) {
        partCount++;
    }

    /* 對每一個分區進行上傳。*/
    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;
        }

    }

    /* 完成分區上傳。*/
    CompleteMultipartUploadRequest request(BucketName, ObjectName);
    request.setUploadId(uploadId);
    request.setPartList(partETagList);

    /* 指定上傳檔案操作時是否覆蓋同名Object。*/
    /* 不指定x-oss-forbid-overwrite時，預設覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為false時，表示允許覆蓋同名Object。*/
    /* 指定x-oss-forbid-overwrite為true時，表示禁止覆蓋同名Object，如果同名Object已存在，程式將報錯。*/ 
    request.MetaData().addHeader("x-oss-forbid-overwrite", "true");
    auto outcome = client.CompleteMultipartUpload(request);

    if (!outcome.isSuccess()) {
            /* 異常處理。*/
            std::cout << "CompleteMultipartUpload fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

      /* 釋放網路等資源。*/
    ShutdownSdk();
    return 0;
}

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