private static List<Type> ReadTypesFromCache(string cacheName, Predicate<Type> predicate, HttpControllerTypeCacheSerializer serializer)
{
try
{
Stream stream = BuildManager.ReadCachedFile(cacheName);
if (stream != null)
{
using (StreamReader reader = new StreamReader(stream))
{
ICollection<Type> deserializedTypes = serializer.DeserializeTypes(reader);
if (deserializedTypes != null && deserializedTypes.All(type => predicate(type)))
{
// If all read types still match the predicate, success!
return deserializedTypes.ToList();
}
}
}
}
catch
{
// cache failures are not considered fatal -- keep running.
}
return null;
}
private static void SaveTypesToCache(string cacheName, IEnumerable<Type> matchingTypes, HttpControllerTypeCacheSerializer serializer)
{
try
{
Stream stream = BuildManager.CreateCachedFile(cacheName);
if (stream != null)
{
using (StreamWriter writer = new StreamWriter(stream))
{
serializer.SerializeTypes(matchingTypes, writer);
}
}
}
catch
{
// cache failures are not considered fatal -- keep running.
}
}
/// <summary>
/// Returns a list of controllers available for the application.
/// </summary>
/// <returns>An <see cref="ICollection{Type}" /> of controllers.</returns>
public override ICollection<Type> GetControllerTypes(IAssembliesResolver assembliesResolver)
{
HttpControllerTypeCacheSerializer serializer = new HttpControllerTypeCacheSerializer();
// First, try reading from the cache on disk
List<Type> matchingTypes = ReadTypesFromCache(TypeCacheName, IsControllerTypePredicate, serializer);
if (matchingTypes != null)
{
return matchingTypes;
}
// If reading from the cache failed, enumerate over every assembly looking for a matching type
matchingTypes = base.GetControllerTypes(assembliesResolver).ToList();
// Finally, save the cache back to disk
SaveTypesToCache(TypeCacheName, matchingTypes, serializer);
return matchingTypes;
}
