How can I cache objects in ASP.NET MVC?

Question

I\'d like to cache objects in ASP.NET MVC. I have a BaseController that I want all Controllers to inherit from. In the BaseController there is a User

Answer 1

I took Will's answer and modified it to make the CacheExtensions class static and to suggest a slight alteration in order to deal with the possibility of Func being null :

public static class CacheExtensions
{

    private static object sync = new object();
    public const int DefaultCacheExpiration = 20;

    /// 

    /// Allows Caching of typed data
    /// 
    /// (
    ///      string.Format("User{0}", _userId), 
    ///      () => Repository.GetUser(_userId));
    ///
    /// ]]>
    /// 
    /// calling object
    /// Cache key
    /// Func that returns the object to store in cache
    /// 
    /// Uses a default cache expiration period as defined in 
    public static T GetOrStore( this Cache cache, string key, Func generator ) {
        return cache.GetOrStore( key, (cache[key] == null && generator != null) ? generator() : default( T ), DefaultCacheExpiration );
    }


    /// 

    /// Allows Caching of typed data
    /// 
    /// (
    ///      string.Format("User{0}", _userId), 
    ///      () => Repository.GetUser(_userId));
    ///
    /// ]]>
    /// 
    /// calling object
    /// Cache key
    /// Func that returns the object to store in cache
    /// Time to expire cache in minutes
    /// 
    public static T GetOrStore( this Cache cache, string key, Func generator, double expireInMinutes ) {
        return cache.GetOrStore( key,  (cache[key] == null && generator != null) ? generator() : default( T ), expireInMinutes );
    }


    /// 

    /// Allows Caching of typed data
    /// 
    /// (
    ///      string.Format("User{0}", _userId),_userId));
    ///
    /// ]]>
    /// 
    /// calling object
    /// Cache key
    /// Object to store in cache
    /// 
    /// Uses a default cache expiration period as defined in 
    public static T GetOrStore( this Cache cache, string key, T obj ) {
        return cache.GetOrStore( key, obj, DefaultCacheExpiration );
    }

    /// 

    /// Allows Caching of typed data
    /// 
    /// (
    ///      string.Format("User{0}", _userId), 
    ///      () => Repository.GetUser(_userId));
    ///
    /// ]]>
    /// 
    /// calling object
    /// Cache key
    /// Object to store in cache
    /// Time to expire cache in minutes
    /// 
    public static T GetOrStore( this Cache cache, string key, T obj, double expireInMinutes ) {
        var result = cache[key];

        if ( result == null ) {

            lock ( sync ) {
                result = cache[key];
                if ( result == null ) {
                    result = obj != null ? obj : default( T );
                    cache.Insert( key, result, null, DateTime.Now.AddMinutes( expireInMinutes ), Cache.NoSlidingExpiration );
                }
            }
        }

        return (T)result;

    }

}

I would also consider taking this a step further to implement a testable Session solution that extends the System.Web.HttpSessionStateBase abstract class.

public static class SessionExtension
{
    /// 

    /// 
    /// 
    /// (
    ///      string.Format("User{0}", _userId), 
    ///      () => Repository.GetUser(_userId));
    ///
    /// ]]>
    /// 
    /// 
    /// 
    /// 
    /// 
    public static T GetOrStore( this HttpSessionStateBase session, string name, Func generator ) {

        var result = session[name];
        if ( result != null )
            return (T)result;

        result = generator != null ? generator() : default( T );
        session.Add( name, result );
        return (T)result;
    }

}