/// <summary>
/// Returns true if data was retrieved
/// </summary>
/// <param name="onRefreshed">true if updated, false if from cache</param>
public async Task <bool> WithRefreshAsync <T>(RequestToken token, string key, bool allowStaleData, bool forceRefresh, FetchedRequestDelegate <T> onRefreshed, Action <bool> onRefreshing, Func <Task <T> > createMethod)
where T : class
{
this.EnsureInitialized();
IDataCacheFilter[] filters = this.Filters.Values.ToArray();
// see if we can use old data
bool canReadCached = true;
foreach (var item in filters)
{
if (!item.CanReadCached(this, key))
{
canReadCached = false;
break;
}
}
T foundData = null;
// use old data if we can
if (allowStaleData && canReadCached && CachedData.ContainsKey(key))
{
foundData = CachedData[key] as T;
if (foundData == null)
{
forceRefresh = true; //had it, but it was bad data
}
}
// see if we need to refresh
if (!forceRefresh)
{
foreach (var item in filters)
{
if (item.RefreshRequired(this, key))
{
forceRefresh = true;
break;
}
}
}
if (foundData != null)
{
if (onRefreshed != null)
{
try
{
onRefreshed(token, false, foundData); // its not fresh
}
catch (Exception ex)
{
this.LogError(ex, "onRefreshed:old");
}
}
}
// get the data if we need to
if (foundData == null || forceRefresh || !canReadCached || !CachedData.ContainsKey(key))
{
// single request at a time
lock (_ExecutingLock)
{
if (this.Executing.Contains(key))
{
return(false);
}
this.Executing.Add(key);
}
try
{
// get the data
foreach (var item in filters)
{
item.OnBeforeItemRetrieved(this, key);
}
if (onRefreshing != null)
{
try
{
onRefreshing(true);
}
catch (Exception ex)
{
this.LogError(ex, "onRefreshing:true");
}
}
T data = null;
if (createMethod != null)
{
data = await createMethod();
}
foreach (var item in filters)
{
item.OnAfterItemRetrieved(this, key, data);
}
if (data != null)
{
bool canWriteToCache = true;
foreach (var item in filters)
{
if (!item.CanSaveToCache(this, key, data))
{
canWriteToCache = false;
break;
}
}
if (canWriteToCache)
{
foreach (var item in filters)
{
item.OnBeforeItemSavedToCache(this, key, data);
}
this.AddToCache(key, data);
foreach (var item in filters)
{
item.OnAfterItemSavedToCache(this, key, data);
}
}
if (onRefreshed != null)
{
try
{
onRefreshed(token, true, data);
}
catch (Exception ex)
{
this.LogError(ex, "onRefreshed:new");
}
}
return(true);
}
else
{
return(false);
}
}
finally
{
lock (_ExecutingLock)
{
this.Executing.Remove(key);
}
if (onRefreshing != null)
{
try
{
onRefreshing(false);
}
catch (Exception ex)
{
this.LogError(ex, "onRefreshing:false");
}
}
}
}
else
{
if (onRefreshing != null)
{
try
{
onRefreshing(false);
}
catch (Exception ex)
{
this.LogError(ex, "onRefreshing:false");
}
}
return(false);
}
}
