Get the settings for sending Amazon SNS SMS messages using an Amazon SDK

  Aws::SDKOptions options;
  Aws::InitAPI(options);
  {
    Aws::SNS::SNSClient sns;

    Aws::SNS::Model::GetSMSAttributesRequest gsmst_req;
    //Set the request to only retrieve the DefaultSMSType setting. 
    //Without the following line, GetSMSAttributes would retrieve all settings.
    gsmst_req.AddAttributes("DefaultSMSType");

    auto gsmst_out = sns.GetSMSAttributes(gsmst_req);

    if (gsmst_out.IsSuccess())
    {
        for (auto const& att : gsmst_out.GetResult().GetAttributes())
        {
            std::cout <<  att.first << ":  " <<  att.second << std::endl;
        }
    }
    else
    {
      std::cout << "Error while getting SMS Type: '" << gsmst_out.GetError().GetMessage()
        << "'" << std::endl;
    }
  }

  Aws::ShutdownAPI(options);

    public static void getSNSAttrutes(SnsClient snsClient,String topicArn ) {

        try {
            GetSubscriptionAttributesRequest request = GetSubscriptionAttributesRequest.builder()
                .subscriptionArn(topicArn)
                .build();

            // Get the Subscription attributes
            GetSubscriptionAttributesResponse res = snsClient.getSubscriptionAttributes(request);
            Map<String, String> map = res.attributes();

            // Iterate through the map
            Iterator iter = map.entrySet().iterator();
            while (iter.hasNext()) {
                Map.Entry entry = (Map.Entry) iter.next();
                System.out.println("[Key] : " + entry.getKey() + " [Value] : " + entry.getValue());
            }

        } catch (SnsException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }

        System.out.println("\n\nStatus was good");
    }

Create the client in a separate module and export it.

import  { SNSClient } from "@aws-sdk/client-sns";
// Set the AWS Region.
const REGION = "REGION"; //e.g. "us-east-1"
// Create SNS service object.
const snsClient = new SNSClient({ region: REGION });
export  { snsClient };

Import the SDK and client modules and call the API.

// Import required AWS SDK clients and commands for Node.js
import {GetSMSAttributesCommand } from "@aws-sdk/client-sns";
import {snsClient } from "./libs/snsClient.js";

// Set the parameters
var params = {
  attributes: [
    "DefaultSMSType",
    "ATTRIBUTE_NAME",
    /* more items */
  ],
};

const run = async () => {
  try {
    const data = await snsClient.send(new GetSMSAttributesCommand(params));
    console.log("Success.",  data);
    return data; // For unit tests.
  } catch (err) {
    console.log("Error", err.stack);
  }
};
run();

require 'vendor/autoload.php';

use Aws\Sns\SnsClient; 
use Aws\Exception\AwsException;

/**
 * Get the type of SMS Message sent by default from the AWS SNS service.
 *
 * This code expects that you have AWS credentials set up per:
 * https://docs.aws.amazon.com/sdk-for-php/v3/developer-guide/guide_credentials.html
 */
 
$SnSclient = new SnsClient([
    'profile' => 'default',
    'region' => 'us-east-1',
    'version' => '2010-03-31'
]);

try {
    $result = $SnSclient->getSMSAttributes([
        'attributes' => ['DefaultSMSType'],
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}