/// <summary>
/// Removes an sql dependecy set on a HttpRuntime.Cache key. This method only removes
/// the dependency, it does not purge the actual item from cache.
/// </summary>
/// <param name="key">The cache key.</param>
public static void RemoveDependecy(string key)
{
SqlConnection con = new SqlConnection(_ConnectionString);
DataAccessManager dam = new DataAccessManager(ConnectionString);
dam.AddInputParameter("@CacheKey", key);
dam.AddInputParameter("@ApplicationId", ClusteredCacheController.ApplicationId);
try { dam.ExecuteNonQuery(GetFormattedStoredProcedureName(SP_DELETE)); }
catch { throw; }
finally
{
switch (ClusteredCacheController.ClusteredCachingMode)
{
case ClusteredCachingMode.ServiceBroker:
#region service broker
string dependencyId = GetDependencyIDFromCacheKey(key);
if (!string.IsNullOrEmpty(dependencyId))
{
_ServiceBrokerDependencies[dependencyId].SqlDependency.OnChange -= OnChange;
_ServiceBrokerDependencies.Remove(dependencyId);
}
#endregion
break;
case ClusteredCachingMode.CheckAtRequest:
CheckAtRequestDependencies.Remove(key);
break;
}
}
}
/// <summary>
/// Removes an sql dependecy set on a HttpRuntime.Cache key. This method only removes
/// the dependency, it does not purge the actual item from cache.
/// </summary>
public static void RemoveAllDependecies()
{
SqlConnection con = new SqlConnection(_ConnectionString);
DataAccessManager dam = new DataAccessManager(ConnectionString);
dam.AddInputParameter("@ApplicationId", ClusteredCacheController.ApplicationId);
try { dam.ExecuteNonQuery(GetFormattedStoredProcedureName(SP_DELETE_ALL)); }
catch { throw; }
finally
{
switch (ClusteredCacheController.ClusteredCachingMode)
{
case ClusteredCachingMode.ServiceBroker:
#region service broker
_ServiceBrokerDependencies.Clear();
#endregion
break;
case ClusteredCachingMode.CheckAtRequest:
CheckAtRequestDependencies.Clear();
break;
}
}
}
/// <summary>
/// Determines whether [is up to date] [the specified key].
/// </summary>
/// <param name="key">The key.</param>
/// <param name="synchTicks">The synch ticks.</param>
/// <returns></returns>
public static ClusteredCachingSynchronizationStatus IsUpToDate(string key, out long synchTicks)
{
#region check whether we can delay the synchronization check
if (ClusteredCacheController.CheckAtRequestIsUpToDateDelayInMilliseconds > 0 &&
CheckAtRequestDependencies.ContainsKey(key) &&
CheckAtRequestDependencies[key].LastChecked.HasValue &&
CheckAtRequestDependencies[key].LastChecked.Value.AddMilliseconds(ClusteredCacheController.CheckAtRequestIsUpToDateDelayInMilliseconds) > DateTime.UtcNow)
{
synchTicks = CheckAtRequestDependencies[key].Ticks;
return(ClusteredCachingSynchronizationStatus.UpToDate);
}
#endregion
DataAccessManager dam = new DataAccessManager(ConnectionString);
dam.AddInputParameter("@CacheKey", key);
dam.AddInputParameter("@ApplicationId", ClusteredCacheController.ApplicationId);
synchTicks = dam.ExecuteScalar <long>(GetFormattedStoredProcedureName(SP_SELECT));
if (synchTicks <= 0)
{
return(ClusteredCachingSynchronizationStatus.RemovedFromCollection);
}
else
{
if (CheckAtRequestDependencies.ContainsKey(key))
{
if (CheckAtRequestDependencies[key].Ticks.Equals(synchTicks))
{
if (ClusteredCacheController.CheckAtRequestIsUpToDateDelayInMilliseconds > 0)
{
CheckAtRequestDependencies[key] = GetCheckAtRequestInfo(synchTicks);
}
return(ClusteredCachingSynchronizationStatus.UpToDate);
}
else
{
return(ClusteredCachingSynchronizationStatus.OutOfDate);
}
}
else
{
return(ClusteredCachingSynchronizationStatus.NotFound);
}
}
}
/// <summary>
/// Adds an object to the HttpRuntime.Cache collection and sets an SQL Dependency on it's
/// key.
/// </summary>
/// <param name="key">The cache key.</param>
/// <param name="item">The item to add to the cache.</param>
/// <param name="priority">The priority.</param>
public static void AddCacheItem(string key, object item, CacheItemPriority priority)
{
if (ClusteredCacheController.ClusteredCachingMode == ClusteredCachingMode.ServiceBroker)
{
if (_ServiceBrokerDependencies.ContainsKey(key))
{
_ServiceBrokerDependencies.Remove(key);
}
}
#region insert/update at database
long utcNow = DateTime.UtcNow.Ticks;
DataAccessManager dam = new DataAccessManager(ConnectionString);
dam.AddInputParameter("@CacheKey", key);
dam.AddInputParameter("@LastUpdate", utcNow);
dam.AddInputParameter("@ApplicationId", ClusteredCacheController.ApplicationId);
dam.ExecuteNonQuery(GetFormattedStoredProcedureName(SP_INSERT_UPDATE));
#endregion
#region add to cache collection
HttpRuntime.Cache.Remove(key);
HttpRuntime.Cache.Insert(key, item, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, priority, null);
#endregion
#region add dependency
switch (ClusteredCacheController.ClusteredCachingMode)
{
case ClusteredCachingMode.ServiceBroker:
#region service broker
SqlConnection con = new SqlConnection(_ConnectionString);
SqlCommand cmd = new SqlCommand(GetFormattedStoredProcedureName(SP_SELECT), con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("@CacheKey", SqlDbType.NVarChar, 256);
cmd.Parameters[0].Value = key;
// Clear any existing notifications
cmd.Notification = null;
// Create the dependency for this command
SqlDependency dependency = new SqlDependency(cmd);
// Add the event handler
dependency.OnChange += new OnChangeEventHandler(OnChange);
#region execute reader
try
{
con.Open();
// Execute the command.
cmd.ExecuteReader();
// Process the DataReader
}
catch (SqlException err)
{
DataAccessManager.ThrowDataAccessManagerException(err, GetFormattedStoredProcedureName(SP_SELECT));
}
finally
{
con.Close();
}
#endregion
_ServiceBrokerDependencies.Add(dependency.Id, new CacheKeySqlDependency()
{
CacheKey = key, SqlDependency = dependency
});
#endregion
break;
case ClusteredCachingMode.CheckAtRequest:
if (CheckAtRequestDependencies.ContainsKey(key))
{
CheckAtRequestDependencies[key] = GetCheckAtRequestInfo(utcNow);
}
else
{
CheckAtRequestDependencies.Add(key, GetCheckAtRequestInfo(utcNow));
}
break;
}
#endregion
}
/// <summary>
/// Gets an item with a specified key from the HttpRuntime.Cache.
/// </summary>
/// <param name="key">The cache key.</param>
/// <param name="loadObj">The delegate returning the item to insert into cache when it doesn't exist.</param>
/// <param name="priority">The priority.</param>
/// <param name="autoInsertDependency">If set to true, a dependency will be automatically created when no cache
/// dependency is currently set. If this value is false and you try to retrieve an item from cache that was not added
/// first, this method will return null.</param>
/// <returns>
/// The cached item when present at HttpRuntime.Cache, the loadObj delegate (which re-adds the item
/// at cache) when the item can't be found at cache, null if the cache item dependency doesn't exist and autoInsertDependency
/// is set to false or the loadObj delegate returned null.
/// </returns>
public static object GetCacheItem(string key, ReloadObjectAtCache loadObj, CacheItemPriority priority, bool autoInsertDependency)
{
object fetchedItem = null;
switch (ClusteredCacheController.ClusteredCachingMode)
{
case ClusteredCachingMode.ServiceBroker:
#region service broker
lock (_CacheLock)
{
if (HttpRuntime.Cache[key] == null)
{
// check whether we have a dependency...
string dependencyId = GetDependencyIDFromCacheKey(key);
if (!string.IsNullOrEmpty(dependencyId) || autoInsertDependency)
{ // we actually have a dependency, so refresh the cache...
try { fetchedItem = loadObj(); }
catch (Exception err) { throw new CachingException("Error at loading object into cache. See the inner exception for further details.", err); }
if (fetchedItem == null)
{ // we can't insert null as an object, so simply return null.
return(null);
}
HttpRuntime.Cache.Insert(key, fetchedItem, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, priority, null);
return(fetchedItem);
}
else
{ // this key doesn't exist and there is no associated dependency, so return null...
return(null);
}
}
return(HttpRuntime.Cache[key]);
}
#endregion
case ClusteredCachingMode.CheckAtRequest:
#region Check at request
long synchTicks = -1;
lock (_CacheLock)
{
ClusteredCachingSynchronizationStatus status = IsUpToDate(key, out synchTicks);
switch (status)
{
case ClusteredCachingSynchronizationStatus.UpToDate:
if (HttpRuntime.Cache[key] == null)
{
try { fetchedItem = loadObj(); }
catch (Exception err) { throw new CachingException("Error at loading object into cache. See the inner exception for further details.", err); }
if (fetchedItem == null)
{ // we can't insert null as an object, so simply return null.
return(null);
}
HttpRuntime.Cache.Insert(key, fetchedItem, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, priority, null);
return(fetchedItem);
}
return(HttpRuntime.Cache[key]);
case ClusteredCachingSynchronizationStatus.OutOfDate:
CheckAtRequestDependencies[key] = GetCheckAtRequestInfo(synchTicks);
HttpRuntime.Cache.Remove(key);
try { fetchedItem = loadObj(); }
catch (Exception err) { throw new CachingException("Error at loading object into cache. See the inner exception for further details.", err); }
if (fetchedItem == null)
{ // we can't insert null as an object, so simply return null.
return(null);
}
HttpRuntime.Cache.Insert(key, fetchedItem, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, priority, null);
return(fetchedItem);
case ClusteredCachingSynchronizationStatus.NotFound:
CheckAtRequestDependencies.Add(key, GetCheckAtRequestInfo(synchTicks));
HttpRuntime.Cache.Remove(key);
try { fetchedItem = loadObj(); }
catch (Exception err) { throw new CachingException("Error at loading object into cache. See the inner exception for further details.", err); }
if (fetchedItem == null)
{ // we can't insert null as an object, so simply return null.
return(null);
}
HttpRuntime.Cache.Insert(key, fetchedItem, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, priority, null);
return(fetchedItem);
case ClusteredCachingSynchronizationStatus.RemovedFromCollection:
if (autoInsertDependency)
{
try { fetchedItem = loadObj(); }
catch (Exception err) { throw new CachingException("Error at loading object into cache. See the inner exception for further details.", err); }
AddCacheItem(key, fetchedItem, priority);
return(fetchedItem);
}
else
{
HttpRuntime.Cache.Remove(key);
CheckAtRequestDependencies.Remove(key);
return(null);
}
}
break;
}
#endregion
}
return(null);
}
