在.NET Core应用中实现Azure Storage临时文件自动过期

当然可以创建指定时间后自动删除的临时文件，Azure Blob Storage提供了更简洁的原生实现方式，无需手动调用HTTP接口。以下是两种推荐方案：

方案一：上传时直接设置Blob过期删除属性 #

直接在上传配置中指定Blob的过期时间，完成上传后Azure会自动在到期时间删除该文件，这是临时文件场景最直接的做法：

public async Task UploadTemporaryFile(Stream fileStream, string path, TimeSpan expirationTime)
{
    var connectionString = "connection string";
    BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
    BlobContainerClient blobContainerClient = blobServiceClient.GetBlobContainerClient("files");
    BlobClient blobClient = blobContainerClient.GetBlobClient(path);
    fileStream.Position = 0;

    BlobUploadOptions uploadOptions = new BlobUploadOptions();
    
    // 保留你原有的内容类型设置逻辑
    var extension = path.Split(".").LastOrDefault();
    if (!string.IsNullOrEmpty(extension) && MimeTypes.Values.ContainsKey(extension))
    {
        var contentType = MimeTypes.Values[extension];
        uploadOptions.HttpHeaders = new BlobHttpHeaders { ContentType = contentType };
    }

    // 设置自动删除的过期时间：当前UTC时间加上指定时长
    uploadOptions.Properties = new BlobProperties
    {
        ExpiresOn = DateTimeOffset.UtcNow.Add(expirationTime)
    };

    await blobClient.UploadAsync(fileStream, uploadOptions);
}

调用示例（创建1小时后自动删除的文件）：

await UploadTemporaryFile(fileStream, "temp/report.pdf", TimeSpan.FromHours(1));

方案二：配置容器级生命周期管理规则 #

如果你的临时文件都存放在特定路径（比如temp/前缀下），可以给容器配置全局生命周期规则，自动清理符合条件的Blob，适合批量管理临时文件的场景：

代码配置规则示例 #

public async Task SetupTemporaryFileCleanupRule()
{
    var connectionString = "connection string";
    BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
    BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient("files");

    var lifecycleRules = new List<ManagementPolicyRule>
    {
        new ManagementPolicyRule
        {
            Name = "AutoDeleteTempFiles",
            Filter = new ManagementPolicyFilter
            {
                PrefixMatch = new List<string> { "temp/" }, // 匹配临时文件路径前缀
                BlobTypes = new List<string> { "blockBlob" }
            },
            Actions = new ManagementPolicyAction
            {
                BaseBlob = new ManagementPolicyBaseBlob
                {
                    Delete = new ManagementPolicyBaseBlobDelete
                    {
                        DaysAfterModificationGreaterThan = 1.0/24 // 1小时换算为天
                    }
                }
            }
        }
    };

    await containerClient.SetManagementPolicyAsync(new ManagementPolicy(lifecycleRules));
}

关于你当前更新代码的说明 #

你手动通过SAS+HttpClient设置过期的方式过于繁琐，且存在不必要的复杂操作：

• Azure.Storage.Blobs SDK已经封装了所有Blob属性配置操作，无需手动构造HTTP请求
• 手动解析连接字符串获取账号信息属于冗余操作，BlobServiceClient已内置处理逻辑
• 所用的x-ms-expiry-time等头部是旧版API用法，最新SDK直接通过属性配置即可实现需求

内容的提问来源于stack exchange，提问作者A. Gladkiy