IIS7下载文件长度 [英] IIS7 downloading file length

问题描述

我下面code文件下载：

I've following code for file download:

        FileInfo fileInfo = new FileInfo(filePath);

        context.Response.Clear();
        context.Response.ContentType = "application/octet-stream";
        context.Response.AddHeader("Content-Disposition", "attachment; filename=" + System.IO.Path.GetFileName(filePath));
        context.Response.AddHeader("Content-Length", fileInfo.Length.ToString());
        context.Response.WriteFile(filePath);
        context.Response.End();

当我在我的本地IIS6运行它，它工作正常。 Web浏览器（IE8的，火狐3.5.2测试，歌剧10）显示之前，我开始下载该文件的文件长度。

When I run it on my local IIS6 it works fine. Web browser (tested on IE8, Firefox 3.5.2, Opera 10) shows file length before I start download the file.

当我运行在远程IIS7这个code，网页浏览器不显示文件长度。文件长度是未知的。

When I run this code on remote IIS7, web browser doesn't shows file length. File length is unknown.

为什么我没有得到文件的长度时，该code IIS7下运行？

Why I don't get file length when this code runs under IIS7?

推荐答案

使用提琴手检查什么实际发送。我的猜测是你得到分块编码作为缓冲的结果被设置为false IIS7服务器上。

Use Fiddler to check what is actually sent. My guess is you are getting chunked encoding as a result of buffering being set to false on the IIS7 server.

BTW，跌落到Response.End调用其相当创伤的事是不必要的（为此事所以是调用清除）。

BTW, drop the Response.End call its quite a traumatic thing to do and is unnecessary (for that matter so is the call to Clear).

修改

严格按照分块编码（这是可取的您的方案）的Content-Length头应该不会是present（见的 RFC2616 4.4节）。这在我看来，IIS7需要独自去执行这一点。其实我有一个经典-ASP方案，其中IIS7时COM code尝试添加一个Content-Length头时，缓冲是关闭抛出一个错误。

Strictly speaking when streaming content with chunked encoding (which is desirable in your scenario) the Content-Length header ought not be present (see RFC2616 Section 4.4.) It seems to me that IIS7 takes it upon itself to enforce this. In fact I've had a Classic-ASP scenario in which IIS7 throws an error when COM code tries to add a Content-Length header when buffering is off.

这是真的很烦，因为尽管在象牙塔委员会想什么，这头给最终用户信息的一个非常有用的棋子。

This is really annoying because despite what the committee in the ivory towers would like, this header give the end user a very useful piece of info.

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