Use web.sitemap to control page access

Question

I was setting up permissions for pages in a ASP.NET website with <location> tags in web.config, something similar to this:

<location path="Users.aspx">
  <system.web>
    <authorization>
      <allow roles="Administrator"/>
      <deny users="*"/>
    </authorization>
  </system.web>
</location>

However, I also have a web.sitemap which basically contains the same information, i.e. which user roles can see/access which pages. A snippet from my web.sitemap:

<?xml version="1.0" encoding="utf-8" ?>
<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
  <siteMapNode title="Home">
    ... lots of nodes here ...
    <siteMapNode url="users.aspx" roles="Administrator" title="users" description="Edit users" />
    ...
  </siteMapNode>
</siteMap>

Is there some kind of nifty way of using web.sitemap only to configure access? The <location> tags are quite verbose, and I don't like having to duplicate this information.

Answer 1

Probably you're looking for SecurityTrimmingEnabled. See this forum post and blog entry for more details.

So Web.config restricts access from direct URL typing and Web.sitemap - from URLs being displayed

Answer 2

Sure, you can define a SiteMapProvider in your web.config, and use the CurrentNode property to get the SiteMapNode related to the requested page.

First declare your siteMap provider (web.config) :

<siteMap enabled="true" defaultProvider="DefaultXmlSiteMapProvider">
  <providers>
    <add siteMapFile="Web.sitemap" name="DefaultXmlSiteMapProvider" securityTrimmingEnabled="true" type="System.Web.XmlSiteMapProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
  </providers>
</siteMap>

Sample code for page access control with CurrentNode (you can do it better ;)) :

bool hasAccess = false;

if (SiteMap.CurrentNode == null)
    throw new ApplicationException("Page not present in SiteMap : " + this.Request.Url.AbsolutePath);

if (SiteMap.CurrentNode.Roles.Count > 0)
{
    // All roles or no roles
    if (SiteMap.CurrentNode.Roles.Contains("*") == true)
    {
        hasAccess = true;
    }
    else
    {
        for (int index = 0; index < SiteMap.CurrentNode.Roles.Count; index++)
        { 
            string role = SiteMap.CurrentNode.Roles[index].ToString();
            hasAccess = HttpContext.Current.User.IsInRole(role);
            if (hasAccess == true)
               break;
        }
    }
}

Note I added the everyone role (*), very usefull.

Answer 3

Here is the code of my own SiteMapProvider which throws an exception where user being requested a page (node) has no right to do that (his role isn't in the list of node's roles)

public class XmlSiteMapProvider : System.Web.XmlSiteMapProvider
{
    public override bool IsAccessibleToUser(HttpContext context, SiteMapNode node)
    {
        var roles = node.Roles.OfType<string>();
        if (roles.Contains("*") || (roles.Count(r => context.User.IsInRole(r)) > 0))
        {
            return true;
        }
        else
        {
            throw new InsufficientRightsException();
        }
    }
}

To implement my own roles logic I also made my own RoleProvider.