private bool SwapIdentifier(DicomFileMessage msg, string patientId, out string errorReason)
{
string to = _swapper.GetSubstitutionFor(patientId, out errorReason);
if (to == null)
{
errorReason = "Swapper " + _swapper + " returned null";
return(false);
}
msg.DicomDataset = msg.DicomDataset.Replace(":[\"" + patientId + "\"]", ":[\"" + to + "\"]");
return(true);
}
public override string GetSubstitutionFor(string toSwap, out string reason)
{
string result;
reason = null;
//lookup in memory
if (!_cache.TryGetValue(toSwap, out result))
{
SemaphoreSlim locket = _locks.GetOrAdd(toSwap, k => new SemaphoreSlim(1, 1));
locket.Wait();
try
{
if (!_cache.TryGetValue(toSwap, out result))
{
// Now try Redis cache
IDatabase db = _redis.GetDatabase();
var val = db.StringGet(toSwap);
//we have a cached answer (which might be null)
if (val.HasValue)
{
result = val.ToString();
Interlocked.Increment(ref CacheHit);
}
else
{
//we have no cached answer from Redis
Interlocked.Increment(ref CacheMiss);
//Go to the hosted swapper
lock (_hostedSwapper)
{
result = _hostedSwapper.GetSubstitutionFor(toSwap, out reason);
}
//and cache the result (even if it is null - no lookup match found)
db.StringSet(toSwap, result ?? NullString, null, When.NotExists);
}
_cache.Set(toSwap, result ?? NullString, new MemoryCacheEntryOptions()
{
Size = 1
});
}
}
finally
{
locket.Release();
}
}
else
{
Interlocked.Increment(ref CacheHit);
}
if (string.Equals(NullString, result))
{
result = null;
reason = $"Value '{toSwap}' was cached in Redis as missing (i.e. no mapping was found)";
}
if (result == null)
{
Interlocked.Increment(ref Fail);
}
else
{
int res = Interlocked.Increment(ref Success);
if (res % 1000 == 0)
{
LogProgress(_logger, LogLevel.Info);
}
}
return(result);
}