net core api 文件下载，断点续传

1、新建 net core api 项目

2、新建自定义的文件流类

public class ResFileStream : FileStream
    {
        public ResFileStream(string path, FileMode mode, FileAccess access) : base(path, mode, access)
        {
        }

        /// <param name="array"></param>
        /// <param name="offset">偏移量</param>
        /// <param name="count">读取的最大字节数</param>
        /// <returns></returns>
        public override int Read(byte[] array, int offset, int count)
        {
            // 此处可以限制下载速度
            //count = 256;
            //Thread.Sleep(10);
            return base.Read(array, offset, count);
        }
    }

3、添加 文件下载 api

/// <summary>
/// 文件下载 断点续传 视频加载
/// </summary>
/// <returns></returns>
[HttpGet]
public IActionResult GetFile()
{
   var filePath = @"H:电影宝贝计划.mp4"; //文件所在路径
   var name = @"宝贝计划.mp4"; //文件名
   ResFileStream fs = new ResFileStream(filePath, FileMode.Open, FileAccess.Read);

   var type = new MediaTypeHeaderValue("video/mp4").MediaType;
   return File(fs, contentType: type, name, enableRangeProcessing: true); //enableRangeProcessing 是否启动断点续传
}