当文件从 VirtualPathProvider 作为 Stream 返回时维护文件的缓存控制属性

发布于 2024-12-17 12:41:24 字数 860 浏览 1 评论 0原文

我已经实现了 VirtualPathProvider，以从 Azure CDN 返回 Azure 网站的主题文件（图像、css）。除了一件事之外它工作得很好：来自 CDN 的文件都将其缓存控制属性设置为“私有”，因此永远不会被缓存。

实际的 blob 的属性设置正确，如果我通过直接 URL（即不通过 VPP）访问它，则缓存控制是正确的。

问题似乎出在 VirtualFile 类的 Open() 方法中，我必须实现该方法才能将文件作为流返回？

public override Stream Open()
    {
        CloudBlobClient client = new CloudBlobClient(cdnURL);
        CloudBlob blob = client.GetBlobReference(blobURL);
        blob.FetchAttributes();
        MemoryStream stream = new MemoryStream();
        BlobRequestOptions options = new BlobRequestOptions();
        options.BlobListingDetails = BlobListingDetails.Metadata;
        blob.DownloadToStream(stream,options);
        stream.Seek(0, SeekOrigin.Begin);
        return stream;
    }

对此进行搜索，我发现大多数人都以另一种方式遇到问题 - 即文件在他们不希望被缓存时被缓存。但是，我找到的所有示例都没有从另一个 URL 引用文件。它们似乎都使用数据库或只是不同的物理路径。

原文

I have implemented a VirtualPathProvider to return Theme files (images,css) for an Azure web site from the Azure CDN. It is working fine apart from one thing: the files that are coming from the CDN all have their cache control property set to "private" and so are never cached.

The actual blobs have their properties set correctly and if I access one by it's direct URL (i.e. not through the VPP) then the cache control is correct.

The problem seems to be in the Open() method of the VirtualFile class I have to implement to return the file as a Stream?

public override Stream Open()
    {
        CloudBlobClient client = new CloudBlobClient(cdnURL);
        CloudBlob blob = client.GetBlobReference(blobURL);
        blob.FetchAttributes();
        MemoryStream stream = new MemoryStream();
        BlobRequestOptions options = new BlobRequestOptions();
        options.BlobListingDetails = BlobListingDetails.Metadata;
        blob.DownloadToStream(stream,options);
        stream.Seek(0, SeekOrigin.Begin);
        return stream;
    }

Searching on this and I find most people have the problem the other way - i.e. files are cached when they don't want them to be. However none of the examples I can find are referencing a file from another URL. They all seem to use databases or just different physical paths.

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自找没趣 2024-12-24 12:41:24

感谢asp.net论坛上的这个答案 http://forums.asp.net/post/4716700 .aspx

我通过添加 Open() 方法解决了该问题：

HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.Public);
HttpContext.Current.Response.Cache.AppendCacheExtension("max-age=86400");

Thanks to this answer on the asp.net forum http://forums.asp.net/post/4716700.aspx

I have resolved the issue by adding in my Open() method:

HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.Public);
HttpContext.Current.Response.Cache.AppendCacheExtension("max-age=86400");

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