ASP.NET MVC UrlHelper.GenerateUrl异常:“无法使用前导..退出顶部目录上方”

这是一个涉及私有实现细节的奇怪的解决方法,但添加以下内容:

HttpContext.Current.Request.ServerVariables.Remove("IIS_WasUrlRewritten");

这样可以避免在中进行内部检查 PathHelper.GenerateClientUrlInternal 查看请求是否被重写。正如参考资料中的评论所暗示的,这很可能会打破某些场景:

// Since the rawUrl represents what the user sees in his browser, it is what we want to use as the base 
// of our absolute paths. For example, consider mysite.example.com/foo, which is internally 
// rewritten to content.example.com/mysite/foo. When we want to generate a link to ~/bar, we want to
// base it from / instead of /foo, otherwise the user ends up seeing mysite.example.com/foo/bar, 
// which is incorrect.

工作溶液 是在Url.Content/UrlHelper.GenerateContentUrl之前插入一行(最佳位置在应用程序_BeginRequest中):

System.Web.HttpContext.Current.Items.Add("IIS_WasUrlRewritten", "false");

我在大学里学过源代码 https://github.com/aspnet/AspNetWebStack/blob/master/src/ 我的堆栈跟踪中的两个类(System.Web.WebPages.Utils.UrlRewriterHelper.cs和System.Web.WebPages.Utils.UrlUtil.cs)中:

System.Web.HttpException (0x80004005): Cannot use a leading .. to exit above the top directory. 
at System.Web.Util.UrlPath.ReduceVirtualPath(String path) 
at System.Web.Util.UrlPath.Reduce(String path) 
at System.Web.VirtualPath.Combine(VirtualPath relativePath) 
at System.Web.VirtualPathUtility.Combine(String basePath, String relativePath) 
at System.Web.WebPages.UrlUtil.GenerateClientUrlInternal(HttpContextBase httpContext, String contentPath) 
at System.Web.WebPages.UrlUtil.GenerateClientUrlInternal(HttpContextBase httpContext, String contentPath) 
at System.Web.WebPages.UrlUtil.GenerateClientUrl(HttpContextBase httpContext, String basePath, String path, Object[] pathParts) 

System.Web.WebPages.Utils.UrlUtil.cs-GenerateClientUrlInternal方法中有代码:

if (!wasRequestRewritten)
            {
                return contentPath;
            }

            // Since the rawUrl represents what the user sees in his browser, it is what we want to use as the base
            // of our absolute paths. For example, consider mysite.example.com/foo, which is internally
            // rewritten to content.example.com/mysite/foo. When we want to generate a link to ~/bar, we want to
            // base it from / instead of /foo, otherwise the user ends up seeing mysite.example.com/foo/bar,
            // which is incorrect.
            string relativeUrlToDestination = MakeRelative(httpContext.Request.Path, contentPath);
            string absoluteUrlToDestination = MakeAbsolute(httpContext.Request.RawUrl, relativeUrlToDestination);
            return absoluteUrlToDestination;

您可以看到作者对url重写路径的注释中出现奇怪的行。另外,原始客户端路径位于HttpContext.Request.RawUrl中,但在Url中它被重写。 期待System.Web.WebPages.Utils.UrlRewriterHelper.cs:

 if (httpContext.Items.Contains(UrlWasRewrittenServerVar))
            {
                return Object.Equals(httpContext.Items[UrlWasRewrittenServerVar], UrlWasRequestRewrittenTrueValue);
            }
            else
            {
                HttpWorkerRequest httpWorkerRequest = (HttpWorkerRequest)httpContext.GetService(typeof(HttpWorkerRequest));
                bool requestWasRewritten = (httpWorkerRequest != null && httpWorkerRequest.GetServerVariable(UrlWasRewrittenServerVar) != null);

                if (requestWasRewritten)
                {
                    httpContext.Items.Add(UrlWasRewrittenServerVar, UrlWasRequestRewrittenTrueValue);
                }
                else
                {
                    httpContext.Items.Add(UrlWasRewrittenServerVar, UrlWasRequestRewrittenFalseValue);
                }

                return requestWasRewritten;
            }

所以Url.Content现在起作用了。

internal static string ReduceVirtualPath(string path)
{
    int length = path.Length;
    int startIndex = 0;
    while (true)
    {
        startIndex = path.IndexOf('.', startIndex);
        if (startIndex < 0)
        {
            return path;
        }
        if (((startIndex == 0) || (path[startIndex - 1] == '/')) && ((((startIndex + 1) == length) || (path[startIndex + 1] == '/')) || ((path[startIndex + 1] == '.') && (((startIndex + 2) == length) || (path[startIndex + 2] == '/')))))
        {
            break;
        }
        startIndex++;
    }
    ArrayList list = new ArrayList();
    StringBuilder builder = new StringBuilder();
    startIndex = 0;
    do
    {
        int num3 = startIndex;
        startIndex = path.IndexOf('/', num3 + 1);
        if (startIndex < 0)
        {
            startIndex = length;
        }
        if ((((startIndex - num3) <= 3) && ((startIndex < 1) || (path[startIndex - 1] == '.'))) && (((num3 + 1) >= length) || (path[num3 + 1] == '.')))
        {
            if ((startIndex - num3) == 3)
            {
                if (list.Count == 0)
                {
                    throw new HttpException(SR.GetString("Cannot_exit_up_top_directory"));
                }
                if ((list.Count == 1) && IsAppRelativePath(path))
                {
                    return ReduceVirtualPath(MakeVirtualPathAppAbsolute(path));
                }
                builder.Length = (int) list[list.Count - 1];
                list.RemoveRange(list.Count - 1, 1);
            }
        }
        else
        {
            list.Add(builder.Length);
            builder.Append(path, num3, startIndex - num3);
        }
    }
    while (startIndex != length);
    string str = builder.ToString();
    if (str.Length != 0)
    {
        return str;
    }
    if ((length > 0) && (path[0] == '/'))
    {
        return "/";
    }
    return ".";
}