Programmatically read the isv.config.xml file

I recently had a need to read settings from the isv.config.xml file at runtime and spent more time than I should have trying to find an elegant way to do this.  In the end I took a rather simple approach, but it has proven quite effective.

The first requirement I had was to utilize the same physical configuration file Microsoft CRM uses, to ensure synchronicity.  To do this I was able to query the physical path to the CRM web site from the system registry and (assuming) the location of the isv.config.xml file is constant we get this:

string fileName = Registry.GetValue(RegistryHive.LocalMachine,
    @"SOFTWARE\Microsoft\MSCRM", "WebSitePath").ToString() +
    "\\_resources\\isv.config.xml";

Next, I wanted to cache the file so it would only need to be reread when the contents had changed.  For this, I used the built-in ASP.NET cache object:

HttpContext.Current.Cache.Add("isv.config.xml", result,
    new CacheDependency(fileName), Cache.NoAbsoluteExpiration,
    Cache.NoSlidingExpiration, CacheItemPriority.Default,
    null);

Now all was left was to read the file from the cache and parse the XML:

public static XmlDocument Document
{
    get
    {
        // First, look in the web cache
        XmlDocument result = (XmlDocument)
            HttpContext.Current.Cache["isv.config.xml"];

        if (result == null)
        {
            // Load the XML configuration
            string fileName = <see code above> ;

            // Import the values
            result = new XmlDocument();
            result.Load(fileName);

            // Cache the result
            HttpContext.Current.Cache.Add( <see code above> );
        }

        return result;
    }
}

The rest is straight XML:

public static XmlNode Configuration
{
    get
    {
        XmlDocument parent = IsvConfig.Document;

        return (parent == null) ? null :
            parent.SelectSingleNode("/configuration");
    }
}

public static XmlNode Entities
{
    get
    {
        XmlNode parent = IsvConfig.Configuration;

        return (parent == null) ? null :
            parent.SelectSingleNode("Entities");
    }
}

public static XmlNode GetEntity(string entityName)
{
    XmlNode parent = IsvConfig.Entities;

    return (parent == null) ? null :
        parent.SelectSingleNode("Entity[@name='" +
        entityName + "']");
}

The rest is up to you... :-)

tags: Microsoft CRM, Customizations, XML