Search code examples
c#asp.nethttphandler

Getting a list of configured HttpHandlers

My Web.Config.xml file is configured a set of supported extensions to clients' http requests. These requests are handled by the same HttpHandler implementation. I use the extensions to enable functionality in the handler. Below is a copy of the structure.

<system.webServer>
    <handlers accessPolicy="Read, Execute, Script">          
        <add name="Handler1" path="*.path1" verb="*" type="namespace.class, assembly" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode" />
        <add name="Handler2" path="*.path2" verb="*" type="namespace.class, assembly" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode" />
        <add name="Handler3" path="*.path3" verb="*" type="namespace.class, assembly" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode" />
        <add name="Handler4" path="*.path4" verb="*" type="namespace.class, assembly" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode" />
    </handlers>        
</system.webServer>

I wish to implement a 5th handler so that clients can make an initial request to get the supported paths (functionality), so that they will not try to make requests that are not supported. I wish to control enabled functionality by adding / removing handlers.

How can I get a list of the configured handlers run-time in my Handler implementation?

I wish to use the list to construct my response.

I have looked at System.Web.Configuration.HttpHandlersSection but when I try to get system.webServer section, I get an System.Configuration.IgnoreSection object back.

Solution

  • I found that to read the system.webServer/handlers, you need to reference the

    Microsoft.Web.Administration.dll

    in place of System.Configuration.

    The dll can be found in the \windows\system32\inetsrv folder when you have enabled the IIS Management Console in Windows features.

    enter image description here

    Here is some sample code:

    /// <summary>
/// Returns a list of configured handler names
/// </summary>
/// <param name="filter">the handler name must contain this value to be included in the list</param>
/// <returns>a list of handler names that matches the filter or all handler names if filter is null</returns>
public static List<string> GetHandlerNames(string filter)
{
    string websiteName = System.Web.Hosting.HostingEnvironment.ApplicationHost.GetSiteName();
    Configuration o = srvMgr.GetWebConfiguration(websiteName);
    ConfigurationElementCollection c1 = o.GetSection("system.webServer/handlers").GetCollection();

    if (filter != null)
    {
        return c1.Where(x => x.GetAttribute("name").Value.ToString().ToLowerInvariant().Contains(filter.ToLowerInvariant())).Select(x => x.GetAttributeValue("name").ToString()).ToList();
    }
    else
    {
        return c1.Select(x => x.GetAttributeValue("name").ToString()).ToList();
    }
}   


/// <summary>
/// Returns a list of configured handler paths 
/// </summary>
/// <param name="filter">the handler name must contain this value to be included in the list</param>
/// <returns>a list of handler paths that matches the filter or all handler paths if filter is null</returns>
public static List<string> GetHandlerPaths(string filter)
{
    string websiteName = System.Web.Hosting.HostingEnvironment.ApplicationHost.GetSiteName();
    Configuration o = srvMgr.GetWebConfiguration(websiteName);
    ConfigurationElementCollection c1 = o.GetSection("system.webServer/handlers").GetCollection();

    if (filter != null)
    {
        return c1.Where(x => x.GetAttribute("name").Value.ToString().ToLowerInvariant().Contains(filter.ToLowerInvariant())).Select(x => x.GetAttributeValue("path").ToString().Replace("*.", "")).ToList();
    }
    else
    {
        return c1.Select(x => x.GetAttributeValue("path").ToString()).ToList();
    }
}