/
BatchGetItemCommand.ts
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/
BatchGetItemCommand.ts
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// smithy-typescript generated code
import { getSerdePlugin } from "@aws-sdk/middleware-serde";
import { HttpRequest as __HttpRequest, HttpResponse as __HttpResponse } from "@aws-sdk/protocol-http";
import { Command as $Command } from "@aws-sdk/smithy-client";
import {
FinalizeHandlerArguments,
Handler,
HandlerExecutionContext,
HttpHandlerOptions as __HttpHandlerOptions,
MetadataBearer as __MetadataBearer,
MiddlewareStack,
SerdeContext as __SerdeContext,
} from "@aws-sdk/types";
import { DynamoDBClientResolvedConfig, ServiceInputTypes, ServiceOutputTypes } from "../DynamoDBClient";
import { BatchGetItemInput, BatchGetItemOutput } from "../models/models_0";
import {
deserializeAws_json1_0BatchGetItemCommand,
serializeAws_json1_0BatchGetItemCommand,
} from "../protocols/Aws_json1_0";
export interface BatchGetItemCommandInput extends BatchGetItemInput {}
export interface BatchGetItemCommandOutput extends BatchGetItemOutput, __MetadataBearer {}
/**
* <p>The <code>BatchGetItem</code> operation returns the attributes of one or more items
* from one or more tables. You identify requested items by primary key.</p>
* <p>A single operation can retrieve up to 16 MB of data, which can contain as many as 100
* items. <code>BatchGetItem</code> returns 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
* <code>UnprocessedKeys</code>. You can use this value to retry the operation starting
* with the next item to get.</p>
* <important>
* <p>If you request more than 100 items, <code>BatchGetItem</code> returns a
* <code>ValidationException</code> with the message "Too many items requested for
* the BatchGetItem call."</p>
* </important>
* <p>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 <code>UnprocessedKeys</code> 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 dataset.</p>
* <p>If <i>none</i> of the items can be processed due to insufficient
* provisioned throughput on all of the tables in the request, then
* <code>BatchGetItem</code> returns a
* <code>ProvisionedThroughputExceededException</code>. If <i>at least
* one</i> of the items is successfully processed, then
* <code>BatchGetItem</code> completes successfully, while returning the keys of the
* unread items in <code>UnprocessedKeys</code>.</p>
* <important>
* <p>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.</p>
* <p>For more information, see <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch Operations and Error Handling</a> in the <i>Amazon DynamoDB
* Developer Guide</i>.</p>
* </important>
* <p>By default, <code>BatchGetItem</code> performs eventually consistent reads on every
* table in the request. If you want strongly consistent reads instead, you can set
* <code>ConsistentRead</code> to <code>true</code> for any or all tables.</p>
* <p>In order to minimize response latency, <code>BatchGetItem</code> retrieves items in
* parallel.</p>
* <p>When designing your application, keep in mind that DynamoDB does not return items in
* any particular order. To help parse the response by item, include the primary key values
* for the items in your request in the <code>ProjectionExpression</code> parameter.</p>
* <p>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="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#CapacityUnitCalculations">Working with Tables</a> in the <i>Amazon DynamoDB Developer
* Guide</i>.</p>
* @example
* Use a bare-bones client and the command you need to make an API call.
* ```javascript
* import { DynamoDBClient, BatchGetItemCommand } from "@aws-sdk/client-dynamodb"; // ES Modules import
* // const { DynamoDBClient, BatchGetItemCommand } = require("@aws-sdk/client-dynamodb"); // CommonJS import
* const client = new DynamoDBClient(config);
* const command = new BatchGetItemCommand(input);
* const response = await client.send(command);
* ```
*
* @see {@link BatchGetItemCommandInput} for command's `input` shape.
* @see {@link BatchGetItemCommandOutput} for command's `response` shape.
* @see {@link DynamoDBClientResolvedConfig | config} for DynamoDBClient's `config` shape.
*
*/
export class BatchGetItemCommand extends $Command<
BatchGetItemCommandInput,
BatchGetItemCommandOutput,
DynamoDBClientResolvedConfig
> {
// Start section: command_properties
// End section: command_properties
constructor(readonly input: BatchGetItemCommandInput) {
// Start section: command_constructor
super();
// End section: command_constructor
}
/**
* @internal
*/
resolveMiddleware(
clientStack: MiddlewareStack<ServiceInputTypes, ServiceOutputTypes>,
configuration: DynamoDBClientResolvedConfig,
options?: __HttpHandlerOptions
): Handler<BatchGetItemCommandInput, BatchGetItemCommandOutput> {
this.middlewareStack.use(getSerdePlugin(configuration, this.serialize, this.deserialize));
const stack = clientStack.concat(this.middlewareStack);
const { logger } = configuration;
const clientName = "DynamoDBClient";
const commandName = "BatchGetItemCommand";
const handlerExecutionContext: HandlerExecutionContext = {
logger,
clientName,
commandName,
inputFilterSensitiveLog: BatchGetItemInput.filterSensitiveLog,
outputFilterSensitiveLog: BatchGetItemOutput.filterSensitiveLog,
};
const { requestHandler } = configuration;
return stack.resolve(
(request: FinalizeHandlerArguments<any>) =>
requestHandler.handle(request.request as __HttpRequest, options || {}),
handlerExecutionContext
);
}
private serialize(input: BatchGetItemCommandInput, context: __SerdeContext): Promise<__HttpRequest> {
return serializeAws_json1_0BatchGetItemCommand(input, context);
}
private deserialize(output: __HttpResponse, context: __SerdeContext): Promise<BatchGetItemCommandOutput> {
return deserializeAws_json1_0BatchGetItemCommand(output, context);
}
// Start section: command_body_extra
// End section: command_body_extra
}