文件 AWS 開發套件範例 GitHub 儲存庫中有更多可用的 AWS SDK 範例
本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。
GetObjectAttributes 搭配 AWS SDK 或 CLI 使用
下列程式碼範例示範如何使用 GetObjectAttributes。
動作範例是大型程式的程式碼摘錄，必須在內容中執行。您可以在下列程式碼範例的內容中看到此動作：
- SDK for C++
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注意
GitHub 上提供更多範例。尋找完整範例，並了解如何在 AWS 程式碼範例儲存庫
中設定和執行。 // ! Routine which retrieves the hash value of an object stored in an S3 bucket. /*! \param bucket: The name of the S3 bucket where the object is stored. \param key: The unique identifier (key) of the object within the S3 bucket. \param hashMethod: The hashing algorithm used to calculate the hash value of the object. \param[out] hashData: The retrieved hash. \param[out] partHashes: The part hashes if available. \param client: The S3 client instance used to retrieve the object. \return bool: Function succeeded. */ bool AwsDoc::S3::retrieveObjectHash(const Aws::String &bucket, const Aws::String &key, AwsDoc::S3::HASH_METHOD hashMethod, Aws::String &hashData, std::vector<Aws::String> *partHashes, const Aws::S3::S3Client &client) { Aws::S3::Model::GetObjectAttributesRequest request; request.SetBucket(bucket); request.SetKey(key); if (hashMethod == MD5) { Aws::Vector<Aws::S3::Model::ObjectAttributes> attributes; attributes.push_back(Aws::S3::Model::ObjectAttributes::ETag); request.SetObjectAttributes(attributes); Aws::S3::Model::GetObjectAttributesOutcome outcome = client.GetObjectAttributes( request); if (outcome.IsSuccess()) { const Aws::S3::Model::GetObjectAttributesResult &result = outcome.GetResult(); hashData = result.GetETag(); } else { std::cerr << "Error retrieving object etag attributes." << outcome.GetError().GetMessage() << std::endl; return false; } } else { // hashMethod != MD5 Aws::Vector<Aws::S3::Model::ObjectAttributes> attributes; attributes.push_back(Aws::S3::Model::ObjectAttributes::Checksum); request.SetObjectAttributes(attributes); Aws::S3::Model::GetObjectAttributesOutcome outcome = client.GetObjectAttributes( request); if (outcome.IsSuccess()) { const Aws::S3::Model::GetObjectAttributesResult &result = outcome.GetResult(); switch (hashMethod) { case AwsDoc::S3::DEFAULT: // NOLINT(*-branch-clone) break; // Default is not supported. #pragma clang diagnostic push #pragma ide diagnostic ignored "UnreachableCode" case AwsDoc::S3::MD5: break; // MD5 is not supported. #pragma clang diagnostic pop case AwsDoc::S3::SHA1: hashData = result.GetChecksum().GetChecksumSHA1(); break; case AwsDoc::S3::SHA256: hashData = result.GetChecksum().GetChecksumSHA256(); break; case AwsDoc::S3::CRC32: hashData = result.GetChecksum().GetChecksumCRC32(); break; case AwsDoc::S3::CRC32C: hashData = result.GetChecksum().GetChecksumCRC32C(); break; default: std::cerr << "Unknown hash method." << std::endl; return false; } } else { std::cerr << "Error retrieving object checksum attributes." << outcome.GetError().GetMessage() << std::endl; return false; } if (nullptr != partHashes) { attributes.clear(); attributes.push_back(Aws::S3::Model::ObjectAttributes::ObjectParts); request.SetObjectAttributes(attributes); outcome = client.GetObjectAttributes(request); if (outcome.IsSuccess()) { const Aws::S3::Model::GetObjectAttributesResult &result = outcome.GetResult(); const Aws::Vector<Aws::S3::Model::ObjectPart> parts = result.GetObjectParts().GetParts(); for (const Aws::S3::Model::ObjectPart &part: parts) { switch (hashMethod) { case AwsDoc::S3::DEFAULT: // Default is not supported. NOLINT(*-branch-clone) break; case AwsDoc::S3::MD5: // MD5 is not supported. break; case AwsDoc::S3::SHA1: partHashes->push_back(part.GetChecksumSHA1()); break; case AwsDoc::S3::SHA256: partHashes->push_back(part.GetChecksumSHA256()); break; case AwsDoc::S3::CRC32: partHashes->push_back(part.GetChecksumCRC32()); break; case AwsDoc::S3::CRC32C: partHashes->push_back(part.GetChecksumCRC32C()); break; default: std::cerr << "Unknown hash method." << std::endl; return false; } } } else { std::cerr << "Error retrieving object attributes for object parts." << outcome.GetError().GetMessage() << std::endl; return false; } } } return true; }-
如需 API 詳細資訊，請參閱AWS SDK for C++ 《 API 參考》中的 GetObjectAttributes。
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