public async Task <Dictionary <string, string> > GetStationReferencesAndNamesForRiver(string riverName)
{
try
{
if (string.IsNullOrWhiteSpace(riverName))
{
throw new ArgumentNullException("riverName");
}
var refNamePairs = new Dictionary <string, string>();
var riverStationsFromCache = (RiverStations)_memoryCache.Get(riverName);
if (riverStationsFromCache != null)
{
if (riverStationsFromCache.Stations != null && riverStationsFromCache.Stations.Any())
{
riverStationsFromCache.Stations.ForEach(s => refNamePairs.Add(s.StationReference, s.Label));
}
}
else
{
var riverNameTokens = riverName.Split(' ');
var newRiverName = (riverNameTokens.Length > 1) ? string.Join("+", riverNameTokens) : riverName;
var requestUrl = string.Format(_config.GetApiRiverStationsUrl(), newRiverName);
var responseData = await _externalService.GetAsync(requestUrl);
var riverStations = JsonConvert.DeserializeObject <RiverStations>(responseData);
if (riverStations != null)
{
if (riverStations.Stations != null && riverStations.Stations.Any())
{
// Add data to cache memory
_memoryCache.AddOrGetExisting(riverName, riverStations);
riverStations.Stations.ForEach(s => refNamePairs.Add(s.StationReference, s.Label));
}
}
}
return(refNamePairs);
}
catch (Exception ex)
{
_logger.LogException(ex, _config.GetDefaultLoggingPath());
return(null);
}
}
private static void Cache <TReturnType>(LOGI.Framework.Toolkit.OpenSource.AspectF.AspectF aspect, ICacheWrapper cacheResolver,
string key, Action work, Func <TReturnType, TReturnType> foundInCache)
{
TReturnType cachedData = cacheResolver.Get <TReturnType>(key);
if (cachedData == null)
{
GetListFromSource <TReturnType>(aspect, cacheResolver, key);
}
else
{
// Give caller a chance to shape the cached item before it is returned
TReturnType cachedType = foundInCache(cachedData);
if (cachedType == null)
{
GetListFromSource <TReturnType>(aspect, cacheResolver, key);
}
else
{
aspect.WorkDelegate = new Func <TReturnType>(() => cachedType);
}
}
work();
}
public static LOGI.Framework.Toolkit.OpenSource.AspectF.AspectF CacheList <TItemType, TListType>(this LOGI.Framework.Toolkit.OpenSource.AspectF.AspectF aspect,
ICacheWrapper cacheResolver, string listCacheKey, Func <TItemType, string> getItemKey)
where TListType : IList <TItemType>, new()
{
return(aspect.Combine(work =>
{
var workDelegate = aspect.WorkDelegate as Func <TListType>;
// Replace the actual work delegate with a new delegate so that
// when the actual work delegate returns a collection, each item
// in the collection is stored in cache individually.
Func <TListType> newWorkDelegate = () =>
{
if (workDelegate != null)
{
TListType collection = workDelegate();
foreach (TItemType item in collection)
{
string key = getItemKey(item);
cacheResolver.Save(key, item);
}
return collection;
}
return default(TListType);
};
aspect.WorkDelegate = newWorkDelegate;
// Get the collection from cache or real source. If collection is returned
// from cache, resolve each item in the collection from cache
Cache <TListType>(aspect, cacheResolver, listCacheKey, work,
cached =>
{
// Get each item from cache. If any of the item is not in cache
// then discard the whole collection from cache and reload the
// collection from source.
var itemList = new TListType();
foreach (TItemType cachedItem in cached.Select(item => cacheResolver.Get <TItemType>(getItemKey(item))))
{
if (null != cachedItem)
{
itemList.Add(cachedItem);
}
else
{
// One of the item is missing from cache. So, discard the
// cached list.
return default(TListType);
}
}
return itemList;
});
}));
}
protected virtual T GetFromCache <T>(string cacheKey)
{
var objectFromSession = cache.Get(cacheKey);
return(objectFromSession == null ? default(T) : (T)objectFromSession);
}
/// <summary>
/// Retrieve or construct the sighting details model
/// </summary>
/// <param name="userName"></param>
/// <returns></returns>
public async Task <SightingDetailsViewModel> GetSightingDetailsModelAsync(string userName, int?sightingId)
{
// Retrieve the model from the cache
string key = GetCacheKey(SightingDetailsKeyPrefix, userName);
SightingDetailsViewModel model = _cache.Get <SightingDetailsViewModel>(key);
if ((model == null) || (model.SightingId != sightingId))
{
// Not cached or the ID has changed, so create a new one and set the "last sighting added" message
string lastAdded = GetLastSightingAddedMessage(userName);
ClearCachedLastSightingAddedMessage(userName);
// If an existing sighting is specified, construct the model using its
// details
if (sightingId != null)
{
Sighting sighting = await _sightings.GetSightingAsync(sightingId ?? 0);
model = new SightingDetailsViewModel
{
SightingId = sightingId,
LastSightingAddedMessage = lastAdded,
Altitude = sighting.Altitude,
Date = sighting.Date,
FlightNumber = sighting.Flight.Number,
LocationId = sighting.LocationId,
Registration = sighting.Aircraft.Registration
};
}
else
{
model = new SightingDetailsViewModel
{
LastSightingAddedMessage = lastAdded,
Date = GetDefaultDate(userName),
LocationId = GetDefaultLocationId(userName)
};
}
}
// Set the available locations
List <Location> locations = await GetLocationsAsync();
model.SetLocations(locations);
return(model);
}
