从亚马逊网络服务S3 .NET核心3.1Web API下载文件

// 引入所需的命名空间
using Amazon.S3;
using Amazon.S3.Model;
using Microsoft.AspNetCore.Mvc;
using System.IO;

// 创建API控制器
[ApiController]
[Route("[controller]")]
public class FileController : ControllerBase
{
    private readonly IAmazonS3 _s3Client;

    // 通过依赖注入获取Amazon S3客户端实例
    public FileController(IAmazonS3 s3Client)
    {
        _s3Client = s3Client;
    }

    // GET请求，接收文件URL作为参数
    [HttpGet("{fileUrl}")]
    public async Task<IActionResult> DownloadFile(string fileUrl)
    {
        try
        {
            // 从S3存储中下载文件
            GetObjectRequest request = new GetObjectRequest
            {
                BucketName = "your-bucket-name",
                Key = "your-file-key"
            };

            using (GetObjectResponse response = await _s3Client.GetObjectAsync(request))
            {
                // 将文件数据写入内存流
                MemoryStream memoryStream = new MemoryStream();
                await response.ResponseStream.CopyToAsync(memoryStream);
                memoryStream.Position = 0;

                // 返回文件流给API的调用者
                return File(memoryStream, "application/octet-stream", "downloaded-file");
            }
        }
        catch (Exception ex)
        {
            // 处理异常情况并返回错误信息
            return StatusCode(500, ex.Message);
        }
    }
}