private Dictionary<string, List<Dictionary<string, AttributeValue>>> GetAttributeItems(bool isAsync)
{
var allItems = new Dictionary<string, List<Dictionary<string, AttributeValue>>>();
if (Batches == null || Batches.Count == 0)
return allItems;
DocumentBatchGet firstBatch = this.Batches[0];
BatchGetItemRequest request = new BatchGetItemRequest();
request.BeforeRequestEvent += isAsync ?
new RequestEventHandler(firstBatch.TargetTable.UserAgentRequestEventHandlerAsync) :
new RequestEventHandler(firstBatch.TargetTable.UserAgentRequestEventHandlerSync);
foreach (var batch in Batches)
{
if (batch.Keys != null && batch.Keys.Count > 0)
{
if (request.RequestItems.ContainsKey(batch.TargetTable.TableName))
{
throw new InvalidOperationException("Multiple batches refer to the same table.");
}
request.RequestItems.Add(
batch.TargetTable.TableName,
new KeysAndAttributes
{
Keys = batch.Keys,
AttributesToGet = batch.AttributesToGet,
ConsistentRead = batch.ConsistentRead
});
}
}
var client = firstBatch.TargetTable.DDBClient;
do
{
var batchGetItemResponse = client.BatchGetItem(request);
var result = batchGetItemResponse.BatchGetItemResult;
var responses = result.Responses;
foreach (var response in responses)
{
string tableName = response.Key;
BatchResponse batchResponse = response.Value;
List<Dictionary<string, AttributeValue>> items = batchResponse.Items;
List<Dictionary<string, AttributeValue>> fetchedItems;
if (!allItems.TryGetValue(tableName, out fetchedItems))
{
fetchedItems = new List<Dictionary<string, AttributeValue>>();
allItems[tableName] = fetchedItems;
}
fetchedItems.AddRange(items);
}
request.RequestItems = result.UnprocessedKeys;
} while (request.RequestItems.Count > 0);
return allItems;
}
IAsyncResult invokeBatchGetItem(BatchGetItemRequest batchGetItemRequest, AsyncCallback callback, object state, bool synchronized)
{
IRequest irequest = new BatchGetItemRequestMarshaller().Marshall(batchGetItemRequest);
var unmarshaller = BatchGetItemResponseUnmarshaller.GetInstance();
AsyncResult result = new AsyncResult(irequest, callback, state, synchronized, signer, unmarshaller);
Invoke(result);
return result;
}
/// <summary>
/// <para>Retrieves the attributes for multiple items from multiple tables using their primary keys.</para> <para>The maximum number of item
/// attributes that can be retrieved for a single operation is 100. Also, the number of items retrieved is constrained by a 1 MB the size limit.
/// If the response size limit is exceeded or a partial result is returned due to an internal processing failure, Amazon DynamoDB returns an
/// <c>UnprocessedKeys</c> value so you can retry the operation starting with the next item to get.</para> <para>Amazon DynamoDB automatically
/// adjusts the number of items returned per page to enforce this limit. For example, even if you ask to retrieve 100 items, but each individual
/// item is 50k in size, the system returns 20 items and an appropriate <c>UnprocessedKeys</c> value so you can get the next page of results. If
/// necessary, your application needs its own logic to assemble the pages of results into one set.</para>
/// </summary>
///
/// <param name="batchGetItemRequest">Container for the necessary parameters to execute the BatchGetItem service method on
/// AmazonDynamoDB.</param>
///
/// <returns>The response from the BatchGetItem service method, as returned by AmazonDynamoDB.</returns>
///
/// <exception cref="ProvisionedThroughputExceededException"/>
/// <exception cref="InternalServerErrorException"/>
/// <exception cref="ResourceNotFoundException"/>
public BatchGetItemResponse BatchGetItem(BatchGetItemRequest batchGetItemRequest)
{
IAsyncResult asyncResult = invokeBatchGetItem(batchGetItemRequest, null, null, true);
return EndBatchGetItem(asyncResult);
}
/// <summary>
/// Initiates the asynchronous execution of the BatchGetItem operation.
/// <seealso cref="Amazon.DynamoDB.AmazonDynamoDB.BatchGetItem"/>
/// </summary>
///
/// <param name="batchGetItemRequest">Container for the necessary parameters to execute the BatchGetItem operation on AmazonDynamoDB.</param>
/// <param name="callback">An AsyncCallback delegate that is invoked when the operation completes.</param>
/// <param name="state">A user-defined state object that is passed to the callback procedure. Retrieve this object from within the callback
/// procedure using the AsyncState property.</param>
///
/// <returns>An IAsyncResult that can be used to poll or wait for results, or both; this value is also needed when invoking EndBatchGetItem
/// operation.</returns>
public IAsyncResult BeginBatchGetItem(BatchGetItemRequest batchGetItemRequest, AsyncCallback callback, object state)
{
return invokeBatchGetItem(batchGetItemRequest, callback, state, false);
}
/// <summary>
/// <para> The BatchGetItem operation returns the attributes for multiple items from multiple tables using their primary keys. The maximum
/// number of item attributes that can be retrieved for a single operation is 100. Also, the number of items retrieved is constrained by a 1 MB
/// the size limit. If the response size limit is exceeded or a partial result is returned due to an internal processing failure, Amazon
/// DynamoDB returns an UnprocessedKeys value so you can retry the operation starting with the next item to get. Amazon DynamoDB automatically
/// adjusts the number of items returned per page to enforce this limit. For example, even if you ask to retrieve 100 items, but each individual
/// item is 50 KB in size, the system returns 20 items and an appropriate UnprocessedKeys value so you can get the next page of results. If
/// necessary, your application needs its own logic to assemble the pages of results into one set. </para>
/// </summary>
///
/// <param name="batchGetItemRequest">Container for the necessary parameters to execute the BatchGetItem service method on
/// AmazonDynamoDB.</param>
///
/// <returns>The response from the BatchGetItem service method, as returned by AmazonDynamoDB.</returns>
///
/// <exception cref="ProvisionedThroughputExceededException"/>
/// <exception cref="InternalServerErrorException"/>
/// <exception cref="ResourceNotFoundException"/>
public BatchGetItemResponse BatchGetItem(BatchGetItemRequest batchGetItemRequest)
{
IRequest<BatchGetItemRequest> request = new BatchGetItemRequestMarshaller().Marshall(batchGetItemRequest);
BatchGetItemResponse response = Invoke<BatchGetItemRequest, BatchGetItemResponse> (request, this.signer, BatchGetItemResponseUnmarshaller.GetInstance());
return response;
}