/// <summary>
/// The <i>BatchGetItem</i> operation returns the attributes of one or more items from
/// one or more tables. You identify requested items by primary key.
///
///
/// <para>
/// A single operation can retrieve up to 16 MB of data, which can contain as many as
/// 100 items. <i>BatchGetItem</i> will return a partial result if the response size limit
/// is exceeded, the table's provisioned throughput is exceeded, or an internal processing
/// failure occurs. If a partial result is returned, the operation returns a value for
/// <i>UnprocessedKeys</i>. You can use this value to retry the operation starting with
/// the next item to get.
/// </para>
/// <important>
/// <para>
/// If you request more than 100 items <i>BatchGetItem</i> will return a <i>ValidationException</i>
/// with the message "Too many items requested for the BatchGetItem call".
/// </para>
/// </important>
/// <para>
/// For example, if you ask to retrieve 100 items, but each individual item is 300 KB
/// in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also
/// returns an appropriate <i>UnprocessedKeys</i> value so you can get the next page of
/// results. If desired, your application can include its own logic to assemble the pages
/// of results into one data set.
/// </para>
///
/// <para>
/// If <i>none</i> of the items can be processed due to insufficient provisioned throughput
/// on all of the tables in the request, then <i>BatchGetItem</i> will return a <i>ProvisionedThroughputExceededException</i>.
/// If <i>at least one</i> of the items is successfully processed, then <i>BatchGetItem</i>
/// completes successfully, while returning the keys of the unread items in <i>UnprocessedKeys</i>.
/// </para>
/// <important>
/// <para>
/// If DynamoDB returns any unprocessed items, you should retry the batch operation on
/// those items. However, <i>we strongly recommend that you use an exponential backoff
/// algorithm</i>. If you retry the batch operation immediately, the underlying read or
/// write requests can still fail due to throttling on the individual tables. If you delay
/// the batch operation using exponential backoff, the individual requests in the batch
/// are much more likely to succeed.
/// </para>
///
/// <para>
/// For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch
/// Operations and Error Handling</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </para>
/// </important>
/// <para>
/// By default, <i>BatchGetItem</i> performs eventually consistent reads on every table
/// in the request. If you want strongly consistent reads instead, you can set <i>ConsistentRead</i>
/// to <code>true</code> for any or all tables.
/// </para>
///
/// <para>
/// In order to minimize response latency, <i>BatchGetItem</i> retrieves items in parallel.
/// </para>
///
/// <para>
/// When designing your application, keep in mind that DynamoDB does not return attributes
/// in any particular order. To help parse the response by item, include the primary key
/// values for the items in your request in the <i>AttributesToGet</i> parameter.
/// </para>
///
/// <para>
/// If a requested item does not exist, it is not returned in the result. Requests for
/// nonexistent items consume the minimum read capacity units according to the type of
/// read. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#CapacityUnitCalculations">Capacity
/// Units Calculations</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </para>
/// </summary>
/// <param name="requestItems">A map of one or more table names and, for each table, a map that describes one or more items to retrieve from that table. Each table name can be used only once per <i>BatchGetItem</i> request. Each element in the map of items to retrieve consists of the following: <ul> <li> <i>ConsistentRead</i> - If <code>true</code>, a strongly consistent read is used; if <code>false</code> (the default), an eventually consistent read is used. </li> <li> <i>ExpressionAttributeNames</i> - One or more substitution tokens for attribute names in the <i>ProjectionExpression</i> parameter. The following are some use cases for using <i>ExpressionAttributeNames</i>: <ul> <li> To access an attribute whose name conflicts with a DynamoDB reserved word. </li> <li> To create a placeholder for repeating occurrences of an attribute name in an expression. </li> <li> To prevent special characters in an attribute name from being misinterpreted in an expression. </li> </ul> Use the <b>#</b> character in an expression to dereference an attribute name. For example, consider the following attribute name: <ul><li><code>Percentile</code></li></ul> The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html">Reserved Words</a> in the <i>Amazon DynamoDB Developer Guide</i>). To work around this, you could specify the following for <i>ExpressionAttributeNames</i>: <ul><li><code>{"#P":"Percentile"}</code></li></ul> You could then use this substitution in an expression, as in this example: <ul><li><code>#P = :val</code></li></ul> <note>Tokens that begin with the <b>:</b> character are <i>expression attribute values</i>, which are placeholders for the actual value at runtime.</note> For more information on expression attribute names, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html">Accessing Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>. </li> <li> <i>Keys</i> - An array of primary key attribute values that define specific items in the table. For each primary key, you must provide <i>all</i> of the key attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide <i>both</i> the hash attribute and the range attribute. </li> <li> <i>ProjectionExpression</i> - A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas. If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html">Accessing Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>. </li> <li> <i>AttributesToGet</i> - <important> This is a legacy parameter, for backward compatibility. New applications should use <i>ProjectionExpression</i> instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a <i>ValidationException</i> exception. This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.</important> The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result. Note that <i>AttributesToGet</i> has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application. </li> </ul></param>
/// <param name="returnConsumedCapacity">A property of BatchGetItemRequest used to execute the BatchGetItem service method.</param>
/// <param name="cancellationToken">
/// A cancellation token that can be used by other objects or threads to receive notice of cancellation.
/// </param>
///
/// <returns>The response from the BatchGetItem service method, as returned by DynamoDB.</returns>
/// <exception cref="Amazon.DynamoDBv2.Model.InternalServerErrorException">
/// An error occurred on the server side.
/// </exception>
/// <exception cref="Amazon.DynamoDBv2.Model.ProvisionedThroughputExceededException">
/// Your request rate is too high. The AWS SDKs for DynamoDB automatically retry requests
/// that receive this exception. Your request is eventually successful, unless your retry
/// queue is too large to finish. Reduce the frequency of requests and use exponential
/// backoff. For more information, go to <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#APIRetries">Error
/// Retries and Exponential Backoff</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </exception>
/// <exception cref="Amazon.DynamoDBv2.Model.ResourceNotFoundException">
/// The operation tried to access a nonexistent table or index. The resource might not
/// be specified correctly, or its status might not be <code>ACTIVE</code>.
/// </exception>
public Task<BatchGetItemResponse> BatchGetItemAsync(Dictionary<string, KeysAndAttributes> requestItems, ReturnConsumedCapacity returnConsumedCapacity, System.Threading.CancellationToken cancellationToken = default(CancellationToken))
{
var request = new BatchGetItemRequest();
request.RequestItems = requestItems;
request.ReturnConsumedCapacity = returnConsumedCapacity;
return BatchGetItemAsync(request, cancellationToken);
}
/// <summary>
/// The <i>BatchGetItem</i> operation returns the attributes of one or more items from
/// one or more tables. You identify requested items by primary key.
///
///
/// <para>
/// A single operation can retrieve up to 16 MB of data, which can contain as many as
/// 100 items. <i>BatchGetItem</i> will return a partial result if the response size limit
/// is exceeded, the table's provisioned throughput is exceeded, or an internal processing
/// failure occurs. If a partial result is returned, the operation returns a value for
/// <i>UnprocessedKeys</i>. You can use this value to retry the operation starting with
/// the next item to get.
/// </para>
///
/// <para>
/// For example, if you ask to retrieve 100 items, but each individual item is 300 KB
/// in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also
/// returns an appropriate <i>UnprocessedKeys</i> value so you can get the next page of
/// results. If desired, your application can include its own logic to assemble the pages
/// of results into one data set.
/// </para>
///
/// <para>
/// If <i>none</i> of the items can be processed due to insufficient provisioned throughput
/// on all of the tables in the request, then <i>BatchGetItem</i> will return a <i>ProvisionedThroughputExceededException</i>.
/// If <i>at least one</i> of the items is successfully processed, then <i>BatchGetItem</i>
/// completes successfully, while returning the keys of the unread items in <i>UnprocessedKeys</i>.
/// </para>
/// <important>
/// <para>
/// If DynamoDB returns any unprocessed items, you should retry the batch operation on
/// those items. However, <i>we strongly recommend that you use an exponential backoff
/// algorithm</i>. If you retry the batch operation immediately, the underlying read or
/// write requests can still fail due to throttling on the individual tables. If you delay
/// the batch operation using exponential backoff, the individual requests in the batch
/// are much more likely to succeed.
/// </para>
///
/// <para>
/// For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch
/// Operations and Error Handling</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </para>
/// </important>
/// <para>
/// By default, <i>BatchGetItem</i> performs eventually consistent reads on every table
/// in the request. If you want strongly consistent reads instead, you can set <i>ConsistentRead</i>
/// to <code>true</code> for any or all tables.
/// </para>
///
/// <para>
/// In order to minimize response latency, <i>BatchGetItem</i> retrieves items in parallel.
/// </para>
///
/// <para>
/// When designing your application, keep in mind that DynamoDB does not return attributes
/// in any particular order. To help parse the response by item, include the primary key
/// values for the items in your request in the <i>AttributesToGet</i> parameter.
/// </para>
///
/// <para>
/// If a requested item does not exist, it is not returned in the result. Requests for
/// nonexistent items consume the minimum read capacity units according to the type of
/// read. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#CapacityUnitCalculations">Capacity
/// Units Calculations</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </para>
/// </summary>
/// <param name="requestItems">A map of one or more table names and, for each table, a map that describes one or more items to retrieve from that table. Each table name can be used only once per <i>BatchGetItem</i> request. Each element in the map of items to retrieve consists of the following: <ul> <li> <i>ConsistentRead</i> - If <code>true</code>, a strongly consistent read is used; if <code>false</code> (the default), an eventually consistent read is used. </li> <li> <i>ExpressionAttributeNames</i> - One or more substitution tokens for attribute names in the <i>ProjectionExpression</i> parameter. The following are some use cases for using <i>ExpressionAttributeNames</i>: <ul> <li> To access an attribute whose name conflicts with a DynamoDB reserved word. </li> <li> To create a placeholder for repeating occurrences of an attribute name in an expression. </li> <li> To prevent special characters in an attribute name from being misinterpreted in an expression. </li> </ul> Use the <b>#</b> character in an expression to dereference an attribute name. For example, consider the following attribute name: <ul><li><code>Percentile</code></li></ul> The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html">Reserved Words</a> in the <i>Amazon DynamoDB Developer Guide</i>). To work around this, you could specify the following for <i>ExpressionAttributeNames</i>: <ul><li><code>{"#P":"Percentile"}</code></li></ul> You could then use this substitution in an expression, as in this example: <ul><li><code>#P = :val</code></li></ul> <note> Tokens that begin with the <b>:</b> character are <i>expression attribute values</i>, which are placeholders for the actual value at runtime.</note> For more information on expression attribute names, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html">Accessing Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>. </li> <li> <i>Keys</i> - An array of primary key attribute values that define specific items in the table. For each primary key, you must provide <i>all</i> of the key attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide <i>both</i> the hash attribute and the range attribute. </li> <li> <i>ProjectionExpression</i> - A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas. If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html">Accessing Item Attributes</a> in the <i>Amazon DynamoDB Developer Guide</i>. </li> <li> <i>AttributesToGet</i> - <important> This is a legacy parameter, for backward compatibility. New applications should use <i>ProjectionExpression</i> instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a <i>ValidationException</i> exception. This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map. </important> The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result. Note that <i>AttributesToGet</i> has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application. </li> </ul></param>
/// <param name="returnConsumedCapacity">A property of BatchGetItemRequest used to execute the BatchGetItem service method.</param>
///
/// <returns>The response from the BatchGetItem service method, as returned by DynamoDB.</returns>
/// <exception cref="Amazon.DynamoDBv2.Model.InternalServerErrorException">
/// An error occurred on the server side.
/// </exception>
/// <exception cref="Amazon.DynamoDBv2.Model.ProvisionedThroughputExceededException">
/// The request rate is too high, or the request is too large, for the available throughput
/// to accommodate. The AWS SDKs automatically retry requests that receive this exception;
/// therefore, your request will eventually succeed, unless the request is too large or
/// your retry queue is too large to finish. Reduce the frequency of requests by using
/// the strategies listed in <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#APIRetries">Error
/// Retries and Exponential Backoff</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </exception>
/// <exception cref="Amazon.DynamoDBv2.Model.ResourceNotFoundException">
/// The operation tried to access a nonexistent table or index. The resource might not
/// be specified correctly, or its status might not be <code>ACTIVE</code>.
/// </exception>
public BatchGetItemResponse BatchGetItem(Dictionary<string, KeysAndAttributes> requestItems, ReturnConsumedCapacity returnConsumedCapacity)
{
var request = new BatchGetItemRequest();
request.RequestItems = requestItems;
request.ReturnConsumedCapacity = returnConsumedCapacity;
return BatchGetItem(request);
}
/// <summary>
/// The <i>BatchGetItem</i> operation returns the attributes of one or more items from
/// one or more tables. You identify requested items by primary key.
///
///
/// <para>
/// A single operation can retrieve up to 16 MB of data, which can contain as many as
/// 100 items. <i>BatchGetItem</i> will return a partial result if the response size limit
/// is exceeded, the table's provisioned throughput is exceeded, or an internal processing
/// failure occurs. If a partial result is returned, the operation returns a value for
/// <i>UnprocessedKeys</i>. You can use this value to retry the operation starting with
/// the next item to get.
/// </para>
///
/// <para>
/// For example, if you ask to retrieve 100 items, but each individual item is 300 KB
/// in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also
/// returns an appropriate <i>UnprocessedKeys</i> value so you can get the next page of
/// results. If desired, your application can include its own logic to assemble the pages
/// of results into one data set.
/// </para>
///
/// <para>
/// If <i>none</i> of the items can be processed due to insufficient provisioned throughput
/// on all of the tables in the request, then <i>BatchGetItem</i> will return a <i>ProvisionedThroughputExceededException</i>.
/// If <i>at least one</i> of the items is successfully processed, then <i>BatchGetItem</i>
/// completes successfully, while returning the keys of the unread items in <i>UnprocessedKeys</i>.
/// </para>
/// <important>
/// <para>
/// If DynamoDB returns any unprocessed items, you should retry the batch operation on
/// those items. However, <i>we strongly recommend that you use an exponential backoff
/// algorithm</i>. If you retry the batch operation immediately, the underlying read or
/// write requests can still fail due to throttling on the individual tables. If you delay
/// the batch operation using exponential backoff, the individual requests in the batch
/// are much more likely to succeed.
/// </para>
///
/// <para>
/// For more information, go to <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch
/// Operations and Error Handling</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </para>
/// </important>
/// <para>
/// By default, <i>BatchGetItem</i> performs eventually consistent reads on every table
/// in the request. If you want strongly consistent reads instead, you can set <i>ConsistentRead</i>
/// to <code>true</code> for any or all tables.
/// </para>
///
/// <para>
/// In order to minimize response latency, <i>BatchGetItem</i> retrieves items in parallel.
/// </para>
///
/// <para>
/// When designing your application, keep in mind that DynamoDB does not return attributes
/// in any particular order. To help parse the response by item, include the primary key
/// values for the items in your request in the <i>AttributesToGet</i> parameter.
/// </para>
///
/// <para>
/// If a requested item does not exist, it is not returned in the result. Requests for
/// nonexistent items consume the minimum read capacity units according to the type of
/// read. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#CapacityUnitCalculations">Capacity
/// Units Calculations</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </para>
/// </summary>
/// <param name="requestItems">A map of one or more table names and, for each table, the corresponding primary keys for the items to retrieve. Each table name can be invoked only once. Each element in the map consists of the following: <ul> <li> <i>Keys</i> - An array of primary key attribute values that define specific items in the table. For each primary key, you must provide <i>all</i> of the key attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide <i>both</i> the hash attribute and the range attribute. </li> <li> <i>AttributesToGet</i> - One or more attributes to be retrieved from the table. By default, all attributes are returned. If a specified attribute is not found, it does not appear in the result. Note that <i>AttributesToGet</i> has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application. </li> <li> <i>ConsistentRead</i> - If <code>true</code>, a strongly consistent read is used; if <code>false</code> (the default), an eventually consistent read is used. </li> </ul></param>
/// <param name="returnConsumedCapacity">A property of BatchGetItemRequest used to execute the BatchGetItem service method.</param>
///
/// <returns>The response from the BatchGetItem service method, as returned by DynamoDB.</returns>
/// <exception cref="Amazon.DynamoDBv2.Model.InternalServerErrorException">
/// An error occurred on the server side.
/// </exception>
/// <exception cref="Amazon.DynamoDBv2.Model.ProvisionedThroughputExceededException">
/// The request rate is too high, or the request is too large, for the available throughput
/// to accommodate. The AWS SDKs automatically retry requests that receive this exception;
/// therefore, your request will eventually succeed, unless the request is too large or
/// your retry queue is too large to finish. Reduce the frequency of requests by using
/// the strategies listed in <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#APIRetries">Error
/// Retries and Exponential Backoff</a> in the <i>Amazon DynamoDB Developer Guide</i>.
/// </exception>
/// <exception cref="Amazon.DynamoDBv2.Model.ResourceNotFoundException">
/// The operation tried to access a nonexistent table or index. The resource might not
/// be specified correctly, or its status might not be <code>ACTIVE</code>.
/// </exception>
public void BatchGetItemAsync(Dictionary<string, KeysAndAttributes> requestItems, ReturnConsumedCapacity returnConsumedCapacity, AmazonServiceCallback<BatchGetItemRequest, BatchGetItemResponse> callback, AsyncOptions options = null)
{
var request = new BatchGetItemRequest();
request.RequestItems = requestItems;
request.ReturnConsumedCapacity = returnConsumedCapacity;
BatchGetItemAsync(request, callback, options);
}