private static async Task <HttpStatusCode> ExecuteDeleteAsync(ITransaction tx, IReliableState dictionary, EntityOperation <JToken, JToken> operation)
{
// Get type information.
Type keyType = dictionary.GetKeyType();
Type valueType = dictionary.GetValueType();
var key = operation.Key.ToObject(keyType);
Type dictionaryType = typeof(IReliableDictionary <,>).MakeGenericType(keyType, valueType);
// Read the existing value.
MethodInfo tryGetMethod = dictionaryType.GetMethod("TryGetValueAsync", new[] { typeof(ITransaction), keyType, typeof(LockMode) });
var tryGetTask = (Task)tryGetMethod.Invoke(dictionary, new[] { tx, key, LockMode.Update });
await tryGetTask.ConfigureAwait(false);
var tryGetResult = tryGetTask.GetPropertyValue <object>("Result");
// Only update the value if it exists.
if (!tryGetResult.GetPropertyValue <bool>("HasValue"))
{
throw new QueryException(HttpStatusCode.NotFound, "Key not found.");
}
// Validate the ETag.
var currentValue = tryGetResult.GetPropertyValue <object>("Value");
var currentEtag = CRC64.ToCRC64(JsonConvert.SerializeObject(currentValue)).ToString();
if (currentEtag != operation.Etag)
{
throw new QueryException(HttpStatusCode.PreconditionFailed, "The value has changed on the server.");
}
// Delete from reliable dictionary.
MethodInfo tryDeleteMethod = dictionaryType.GetMethod("TryRemoveAsync", new[] { typeof(ITransaction), keyType });
await((Task)tryDeleteMethod.Invoke(dictionary, new[] { tx, key })).ConfigureAwait(false);
return(HttpStatusCode.OK);
}
private static async Task <HttpStatusCode> ExecuteAddAsync(ITransaction tx, IReliableState dictionary, EntityOperation <JToken, JToken> operation)
{
// Get type information.
Type keyType = dictionary.GetKeyType();
Type valueType = dictionary.GetValueType();
var key = operation.Key.ToObject(keyType);
var value = operation.Value.ToObject(valueType);
Type dictionaryType = typeof(IReliableDictionary <,>).MakeGenericType(keyType, valueType);
// Add to reliable dictionary.
MethodInfo tryAddMethod = dictionaryType.GetMethod("TryAddAsync", new[] { typeof(ITransaction), keyType, valueType });
bool success = await((Task <bool>)tryAddMethod.Invoke(dictionary, new[] { tx, key, value })).ConfigureAwait(false);
if (!success)
{
throw new QueryException(HttpStatusCode.Conflict, "Key already exists.");
}
return(HttpStatusCode.OK);
}
