IE 8和客户端缓存 [英] IE 8 and client-side caching

问题描述

故事背景：

我有一个IIS 6 Web服务器上的.NET 3.5的门户网站。目前有被赋予一个值，并根据该值查找上的web服务的PDF文件，并​​显示在网页另一标签的结果给用户的页面。这是一个具有以下code完成的。

I have a web portal in .NET 3.5 on an IIS 6 web server. Currently there is a page that is given a value and based on that value looks up a PDF file on a web service and displays the results to the user in another tab in the web page. This is done with the following code.

 context.Response.ClearContent();
 context.Response.ClearHeaders();
 context.Response.Clear();
 context.Response.AddHeader("Accept-Header", pdfStream.Length.ToString());                                               
 context.Response.ContentType = "application/pdf";
 context.Response.BinaryWrite(pdfStream.ToArray());
 context.Response.Flush();

此工作，并已工作多年。然而，我们得到了一个特定的客户端是具有PDF，直到它们被清除临时Internet缓存每次都返回相同的PDF客户端的问题。

This works and has worked for years. However we got an issue from the client that a particular client was having the PDF returned as the same PDF every time until they cleared temp internet cache.

我想爽哦，这是一个轻松的一年。我刚才添加的缓存头，以应对从未进行缓存。所以我添加以下内容：

I thought oh cool, this is an easy one. I will just add the cache headers to the response to never cache it. So I added the following:

context.Response.Cache.SetCacheability(HttpCacheability.NoCache);//IE set to not cache
context.Response.Cache.SetNoStore();//Firefox/Chrome not to cache
context.Response.Cache.SetExpires(DateTime.UtcNow); //for safe measure expire it immediately 

快速测试我有什么，我期待在响应头。之后

After a quick test I got exactly what I was expecting in the response header.

Cache-Control    no-cache, no-store 
Pragma    no-cache 
Expires    -1 

问题：

所以这个去住。一切似乎一个凉爽的一天。之后的日子，咣当，大家都开始变得白屏幕，没有显示PDF。经过进一步调查，我发现这是只有IE 6,7,8。 Chrome是精细，精细的Firefox和Safari罚款，甚至是IE 9的罚款。不知道为什么会这样，我恢复了我的变化，并部署它，一切又重新开始工作。

So this went live. Everything seemed cool day one. The day after, bam, everyone started getting white screens and no PDF displayed. After further investigation, I found out it was only IE 6,7,8. Chrome is fine, Firefox fine, safari fine, even IE 9 fine. Without knowing the why this happened, I reverted my change and deployed it, and everything started worked again.

我已经找遍了试图找出为什么我的缓存头似乎混淆IE 6-8无济于事。有没有人经历了与IE 6-8此类问题？有我丢失的东西？感谢您的任何见解。

I have searched all over trying to find out why my caching headers seemed to confuse IE 6-8 to no avail. Has anyone experienced this type of issue with IE 6-8? Is there something I am missing? Thanks for any insight.

推荐答案

我找到了解决办法。以下是放倒我。 这里是一个链接

I found the solution. Here is what tipped me off. Here is a link

基本上IE8（或更低）是有与Cache-Control头的问题，如果它有无缓存或存储缓存。我能够通过基本上只允许私有缓存来解决问题，并设置一个最大年龄很短，因此几乎立即过期。

Basically IE8 (and lower) was having issues with the Cache-Control header if it had no-cache or store-cache. I was able to work around the problem by basically allowing private caching only and set a max age to very short so it expires almost immediately.

//Ie 8 and lower have an issue with the "Cache-Control no-cache" and "Cache-Control store-cache" headers.
//The work around is allowing private caching only but immediately expire it.
if ((Request.Browser.Browser.ToLower() == "ie") && (Request.Browser.MajorVersion < 9))
{
     context.Response.Cache.SetCacheability(HttpCacheability.Private);
     context.Response.Cache.SetMaxAge(TimeSpan.FromMilliseconds(1));
}
else
{
     context.Response.Cache.SetCacheability(HttpCacheability.NoCache);//IE set to not cache
     context.Response.Cache.SetNoStore();//Firefox/Chrome not to cache
     context.Response.Cache.SetExpires(DateTime.UtcNow); //for safe measure expire it immediately
}

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