Dotnet core:从 Web API 将字节数组作为文件发送，而不将其保存到磁盘

Question

我有一个 Web api，需要让用户下载/内联我保存到数据库的二进制文件。

到目前为止，我可以像这样实现它：

string ContentType = (string) (result["content_type"] ?? "");
string FileName = (string) (result["file_name"] ?? "");
byte[] content = (byte[]) result["data"];
Stream stream = new MemoryStream(content);
var fullFileName = Path.GetTempFileName();
File.WriteAllBytes(fullFileName, content);
_res.ContentType = ContentType;
_res.StatusCode = (int)HttpStatusCode.OK;
_res.Headers.Add("Content-Disposition", $"{Disposition}; filename="{FileName}"");
await _res.SendFileAsync(fullFileName);

我想知道如何将内存流直接发送到响应，以避免将文件保存到磁盘。

Answer 1

您需要使用HttpResponse.BinaryWrite或MemoryStream.WriteTo：

Response.Clear();
Response.ContentType = "application/vnd.ms-excel";
Response.AddHeader("Content-Disposition", "attachment; filename=file.xls");
Response.BinaryWrite(myByteArray);
// myMemoryStream.WriteTo(Response.OutputStream);
Response.Flush();
Response.Close();
HttpContext.Current.ApplicationInstance.CompleteRequest();

Answer 2

我找到了更简单的方法

string ContentType = (string) (result["content_type"] ?? "");
string FileName = (string) (result["file_name"] ?? "");
byte[] content = (byte[]) result["data"];
_res.ContentType = ContentType;
_res.ContentLength = content.Length;
_res.StatusCode = (int)HttpStatusCode.OK;
_res.Headers.Add("Content-Disposition", $"{Disposition}; filename="{FileName}"");
await _res.Body.WriteAsync(content, 0, content.Length);