Sharing Data Between Web Front Ends With Thread Safe Web Properties

Remember back in the old days when you only had one frontend? Remember when you thought that was complex?

Times have changed and now for almost every production environment you have several frontends and that’s good, the performance is boosted and with SharePoint it’s simple to add one more if you feel you are falling short but this has also taken some tasks to a new level of complexity.

There is software out there like AppFabric that will allow you to persist data and share it between all your servers and they are good… but would you install and configure them everywhere just for sharing a 10 character string?

Well you don’t have to. You can use SharePoint Web Properties to do so. They are fast to write, to read, to code and you don’t need to configure anything.

SharePoint Web Properties are a bit tricky to use though, just a bit, particularly when you are using them in a multithreaded process but I hope these wrappers save you some time. (I have used them in a couple scenarios and work as expected but I can’t assure they are completely safe.)

static object PropertyWriteLock = new object();

/// <summary>
/// Sets a web property to a given value. This method is thread safe.
/// </summary>
/// <param name="Key">The Key for the web property (case insensitive)</param>
/// <param name="Value">Value to set the property to</param>
public static void SetWebProperty(this SPWeb Web, string Key, string Value)
{
    Key = Key.ToLower();
    lock (PropertyWriteLock) //It's better to have a lock just for the key we are working with. I'll post the trick maybe tomorrow.
    {
        if (GetWebPropertyThreadSafe(Web, Key) != Value)
        {
            Web.Properties[Key] = Value;

            Web.Properties.Update();
        }
    }
}

/// <summary>
/// Returns the web property with the given key. This method is thread safe.
/// </summary>
/// <param name="Key">The Key for the web property (case insensitive)</param>
/// <returns>Returns null if not found</returns>
public static string GetWebPropertyThreadSafe(this SPWeb Web, string Key)
{
    Key = Key.ToLower();
    using (SPSite site = new SPSite(Web.Site.ID))
    {
        using (SPWeb newWeb = site.OpenWeb(Web.ID))
        {
            return newWeb.GetWebProperty(Key);
        }
    }
}

/// <summary>
/// Returns the web property with the given key.
/// </summary>
/// <param name="Key">The Key for the web property (case insensitive)</param>
/// <returns>Returns null if not found</returns>
public static string GetWebProperty(this SPWeb Web, string Key)
{
    Key = Key.ToLower();

    return Web.Properties[Key];
}

/// <summary>
/// Removes the web property from the web
/// </summary>
/// <param name="Key">The Key for the web property (case insensitive)</param>
/// <remarks>The web property will remain there but set to null.</remarks>
public static void RemoveWebProperty(this SPWeb Web, string Key)
{
    if (Web.Properties.ContainsKey(Key))
        Web.Properties.Remove(Key);

    Web.Properties.Update();

    if (Web.AllProperties.ContainsKey(Key))
        Web.AllProperties.Remove(Key);

    Web.Update();
}

They have simplified some parts of my application a lot and, I’ll  say that again, they are fast. Give them a go and let me know your thoughts.