FileStreamResult 无法识别 Asp.Net Core 2.2 中的多个 http 范围答案

【问题标题】：FileStreamResult doesn't recognize multiple http ranges in Asp.Net Core 2.2FileStreamResult 无法识别 Asp.Net Core 2.2 中的多个 http 范围
【发布时间】：2019-11-02 17:51:31
【问题描述】：

我有这么简单的端点：

[HttpGet]
public IActionResult GetFileDirect()
{
     var path = ...; // path to the file
     return File(System.IO.File.OpenRead(path), "text/plain", true);
}

当前文件内容：

abcdefghijklmnopqrstuvwxyz

正如您在返回语句中看到的，我将 true 传递给 enableRangeProcessing。在单范围请求的情况下，它可以按预期工作：

curl -H Range:bytes=0-8 http://localhost:65318/api/File -i

回复如下：

HTTP/1.1 206 Partial Content
Content-Length: 9
Content-Type: text/plain
Content-Range: bytes 0-8/26
Accept-Ranges: bytes
Server: Kestrel
X-SourceFiles: =?UTF-8?B?QzpcVXNlcnNcY2ViaXlcRGVza3RvcFxSYW5nZVdlYlxSYW5nZVdlYlxhcGlcRmlsZQ==?=
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Date: Sat, 02 Nov 2019 17:46:49 GMT

abcdefghi

但是，在多范围请求的情况下，它不会考虑任何范围，并会返回带有文件全部内容的Ok 响应：

curl -H  Range:bytes=0-8,12-15 http://localhost:65318/api/File -i

回复如下：

HTTP/1.1 200 OK
Content-Length: 26
Content-Type: text/plain
Accept-Ranges: bytes
Server: Kestrel
X-SourceFiles: =?UTF-8?B?QzpcVXNlcnNcY2ViaXlcRGVza3RvcFxSYW5nZVdlYlxSYW5nZVdlYlxhcGlcRmlsZQ==?=
X-Powered-By: ASP.NET
Date: Sat, 02 Nov 2019 17:49:37 GMT

abcdefghijklmnopqrstuvwxyz

【问题讨论】：

查看源代码以及它如何处理范围标头github.com/aspnet/AspNetCore/blob/master/src/Mvc/Mvc.Core/src/…
无法解析请求中的范围。

标签： c# asp.net-core curl .net-core http-range

【解决方案1】：

我比@Nkosi 更深入地研究了源代码，以找到解析范围的地方，请看AspNetCore - RangeHelper.cs

if (rawRangeHeader.Count > 1 || rawRangeHeader[0].IndexOf(',') >= 0)
{
    logger.LogDebug("Multiple ranges are not supported.");

    // The spec allows for multiple ranges but we choose not to support them because the client may request
    // very strange ranges (e.g. each byte separately, overlapping ranges, etc.) that could negatively
    // impact the server. Ignore the header and serve the response normally.               
    return (false, null);
}

【讨论】：