I got a question in the post I wrote about ASP.NET Output Cache Provider which asks whether we can change the cache provider during runtime.
This post will try to answer the question.
Overriding the OutputCache Provider
One of the changes in ASP.NET 4 is the ability to override the OutputCache
provider name in the Global.asax file. This enables us to create logic that stores the OutputCache
in more than one type of cache according to some state or behavior. When you do that, you need to supply the name of the OutputCache
provider by overriding the GetOutputCacheProviderName
method. For example, I register the OutputCache
provider from the previous post in the web.config, but I don't indicate that it is my default provider:
<caching>
<outputCache>
<providers>
<add name="InMemory" type="InMemoryOutputCacheProvider"/>
</providers>
</outputCache>
</caching>
If I run the application now, the default OutputCache
will be the ASP.NET supplied OutputCache
. If I would like to override it, then the following code which will be written in the Global.asax file will help me achieve it:
public class Global : System.Web.HttpApplication
{
public override string GetOutputCacheProviderName(HttpContext context)
{
return "InMemory";
}
protected void Application_Start(object sender, EventArgs e)
{
}
protected void Session_Start(object sender, EventArgs e)
{
}
protected void Application_BeginRequest(object sender, EventArgs e)
{
}
protected void Application_AuthenticateRequest(object sender, EventArgs e)
{
}
protected void Application_Error(object sender, EventArgs e)
{
}
protected void Session_End(object sender, EventArgs e)
{
}
protected void Application_End(object sender, EventArgs e)
{
}
}
Pay attention that I return the provider name that was registered earlier in the configuration file. Also, I could have provided whatever behavior I want in order to return my needed provider per some situation.
The scope of the GetOutputCacheProviderName
method is per request which means that every request can get its own OutputCache
provider.
Summary
To sum up, we can register more than one OutputCache
provider to our application and decide according to some behavior when to use them. The way to achieve that is by overriding the GetOutputCacheProviderName
method and returning the desired provider.