A Coder's Blog
ActionFilterAttribute is an abstract class upon which action filters are based. It allows the creation of custom action filters.
There are 4 methods that a custom action filter that implements ActionFilterAttribute can override:
I created a simple custom action filter. The purpose of this filter is to clear a portion or the entire content of the cache once a particular controller action is hit.
public class ClearCache : ActionFilterAttribute
{
public bool ClearAll { get; set; }
public string Key { get; set; }
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var cacheProvider = new SimpleCacheProvider();
if (ClearAll)
{
cacheProvider.ClearAll();
}
if (!String.IsNullOrEmpty(Key))
{
cacheProvider.Clear(Key);
}
}
}I added 2 properties, ClearAll to clear the entire content of the cache and Key, to clear a specific key/value from the cache.
This is the simple implementation that I wrote for the cache provider:
public interface ICacheProvider
{
bool Get<T>(string key, out T value);
void Set<T>(string key, T value);
void Set<T>(string key, T value, int duration);
void Clear(string key);
void ClearAll();
}
public class SimpleCacheProvider : ICacheProvider
{
private readonly int defaultCacheDurationInMinutes = 30;
private Cache cache;
public SimpleCacheProvider()
{
cache = HttpRuntime.Cache;
}
public void Clear(string key)
{
cache.Remove(key);
}
public void ClearAll()
{
List<string> keys = new List<string>();
foreach (DictionaryEntry item in cache)
{
keys.Add(item.Key as string);
}
keys.ForEach(x => cache.Remove(x));
}
public bool Get<T>(string key, out T value)
{
try
{
if (cache[key] == null)
{
value = default(T);
return false;
}
value = (T)cache[key];
}
catch
{
value = default(T);
return false;
}
return true;
}
public void Set<T>(string key, T value)
{
Set<T>(key, value, defaultCacheDurationInMinutes);
}
public void Set<T>(string key, T value, int duration)
{
cache.Insert(key,value,null, DateTime.Now.AddMinutes(duration), TimeSpan.Zero);
}
} [ClearCache(ClearAll = true)]
public ActionResult TestActionX()
{
return View();
}
[ClearCache(Key = "test")]
public ActionResult TestActionY()
{
return View();
}