当我将大文件上传到 ASP.NET Core 中的 Web API 时，运行时会在触发处理和存储上传的函数之前将文件加载到内存中。对于大量上传，这成为一个问题，因为它既慢又需要更多内存。对于以前版本的 ASP.NET there are some articles关于如何禁用请求缓冲，但我找不到任何关于如何使用 ASP.NET Core 执行此操作的信息。是否可以禁用请求缓冲，这样我的服务器就不会一直用完内存？
最佳答案
使用 Microsoft.AspNetCore.WebUtilities.MultipartReader 因为它...
can parse any stream [with] minimal buffering. It gives you the headers and body of each section one at a time and then you do what you want with the body of that section (buffer, discard, write to disk, etc.).
这是一个中间件示例。
app.Use(async (context, next) =>
{
if (!IsMultipartContentType(context.Request.ContentType))
{
await next();
return;
}
var boundary = GetBoundary(context.Request.ContentType);
var reader = new MultipartReader(boundary, context.Request.Body);
var section = await reader.ReadNextSectionAsync();
while (section != null)
{
// process each image
const int chunkSize = 1024;
var buffer = new byte[chunkSize];
var bytesRead = 0;
var fileName = GetFileName(section.ContentDisposition);
using (var stream = new FileStream(fileName, FileMode.Append))
{
do
{
bytesRead = await section.Body.ReadAsync(buffer, 0, buffer.Length);
stream.Write(buffer, 0, bytesRead);
} while (bytesRead > 0);
}
section = await reader.ReadNextSectionAsync();
}
context.Response.WriteAsync("Done.");
});
这是 helper 。
private static bool IsMultipartContentType(string contentType)
{
return
!string.IsNullOrEmpty(contentType) &&
contentType.IndexOf("multipart/", StringComparison.OrdinalIgnoreCase) >= 0;
}
private static string GetBoundary(string contentType)
{
var elements = contentType.Split(' ');
var element = elements.Where(entry => entry.StartsWith("boundary=")).First();
var boundary = element.Substring("boundary=".Length);
// Remove quotes
if (boundary.Length >= 2 && boundary[0] == '"' &&
boundary[boundary.Length - 1] == '"')
{
boundary = boundary.Substring(1, boundary.Length - 2);
}
return boundary;
}
private string GetFileName(string contentDisposition)
{
return contentDisposition
.Split(';')
.SingleOrDefault(part => part.Contains("filename"))
.Split('=')
.Last()
.Trim('"');
}
外部引用
关于c# - 处理 ASP.NET Core 1.0 上的大文件上传，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36437282/