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133 lines (113 loc) · 4.65 KB
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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
/**
* Before running this C++ code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-cpp/v1/developer-guide/getting-started.html
*
* For information on the structure of the code examples and how to build and run the examples, see
* https://docs.aws.amazon.com/sdk-for-cpp/v1/developer-guide/getting-started-code-examples.html.
*
**/
#include <aws/core/Aws.h>
#include <aws/dynamodb/DynamoDBClient.h>
#include <aws/dynamodb/model/AttributeDefinition.h>
#include <aws/dynamodb/model/ScanRequest.h>
#include <iostream>
#include "dynamodb_samples.h"
// snippet-start:[dynamodb.cpp.scan_table.code]
//! Scan an Amazon DynamoDB table.
/*!
\sa scanTable()
\param tableName: Name for the DynamoDB table.
\param projectionExpression: An optional projection expression, ignored if empty.
\param clientConfiguration: AWS client configuration.
\return bool: Function succeeded.
*/
bool AwsDoc::DynamoDB::scanTable(const Aws::String &tableName,
const Aws::String &projectionExpression,
const Aws::Client::ClientConfiguration &clientConfiguration) {
Aws::DynamoDB::DynamoDBClient dynamoClient(clientConfiguration);
Aws::DynamoDB::Model::ScanRequest request;
request.SetTableName(tableName);
if (!projectionExpression.empty())
request.SetProjectionExpression(projectionExpression);
Aws::Vector<Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue>> all_items;
Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue> last_evaluated_key; // Used for pagination;
do {
if (!last_evaluated_key.empty()) {
request.SetExclusiveStartKey(last_evaluated_key);
}
const Aws::DynamoDB::Model::ScanOutcome &outcome = dynamoClient.Scan(request);
if (outcome.IsSuccess()) {
// Reference the retrieved items.
const Aws::Vector<Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue>> &items = outcome.GetResult().GetItems();
all_items.insert(all_items.end(), items.begin(), items.end());
last_evaluated_key = outcome.GetResult().GetLastEvaluatedKey();
}
else {
std::cerr << "Failed to Scan items: " << outcome.GetError().GetMessage()
<< std::endl;
return false;
}
} while (!last_evaluated_key.empty());
if (!all_items.empty()) {
std::cout << "Number of items retrieved from scan: " << all_items.size()
<< std::endl;
// Iterate each item and print.
for (const Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue> &itemMap: all_items) {
std::cout << "******************************************************"
<< std::endl;
// Output each retrieved field and its value.
for (const auto &itemEntry: itemMap)
std::cout << itemEntry.first << ": " << itemEntry.second.GetS()
<< std::endl;
}
}
else {
std::cout << "No items found in table: " << tableName << std::endl;
}
return true;
}
// snippet-end:[dynamodb.cpp.scan_table.code]
/*
* main function
*
* Usage: 'run_scan_table <table> [projection_expression]'
*
* Prerequisites: Create a pre-populated DynamoDB table.
*
* For instructions on populating a table with sample data, see
* https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/SampleData.html.
*
*/
#ifndef TESTING_BUILD
int main(int argc, char **argv) {
if (argc < 2) {
std::cout << R"(
Usage:
run_scan_table <table> [projection_expression]
Where:
table - The table to scan.
To limit the fields returned from the table, add
an optional projection expression (a quote-delimited,
comma-separated list of attributes to retrieve).
)";
return 1;
}
Aws::SDKOptions options;
Aws::InitAPI(options);
{
const Aws::String tableName = (argv[1]);
const Aws::String projectionExpression(argc > 2 ? argv[2] : "");
Aws::Client::ClientConfiguration clientConfig;
// Optional: Set to the AWS Region (overrides config file).
// clientConfig.region = "us-east-1";
AwsDoc::DynamoDB::scanTable(tableName, projectionExpression, clientConfig);
}
Aws::ShutdownAPI(options);
return 0;
}
#endif // TESTING_BUILD