# Hello Amazon SNS
Hello Amazon SNS

The following code examples show how to get started using Amazon SNS.

------
#### [ .NET ]

**SDK for .NET**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/dotnetv3/cross-service/TopicsAndQueues#code-examples). 

```
using Amazon.SimpleNotificationService;
using Amazon.SimpleNotificationService.Model;

namespace SNSActions;

public static class HelloSNS
{
    static async Task Main(string[] args)
    {
        var snsClient = new AmazonSimpleNotificationServiceClient();

        Console.WriteLine($"Hello Amazon SNS! Following are some of your topics:");
        Console.WriteLine();

        // You can use await and any of the async methods to get a response.
        // Let's get a list of topics.
        var response = await snsClient.ListTopicsAsync(
            new ListTopicsRequest());

        foreach (var topic in response.Topics)
        {
            Console.WriteLine($"\tTopic ARN: {topic.TopicArn}");
            Console.WriteLine();
        }
    }
}
```
+  For API details, see [ListTopics](https://docs.aws.amazon.com/goto/DotNetSDKV3/sns-2010-03-31/ListTopics) in *AWS SDK for .NET API Reference*. 

------
#### [ C\$1\$1 ]

**SDK for C\$1\$1**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/sns/hello_sns#code-examples). 
Code for the CMakeLists.txt CMake file.  

```
# Set the minimum required version of CMake for this project.
cmake_minimum_required(VERSION 3.13)

# Set the AWS service components used by this project.
set(SERVICE_COMPONENTS sns)

# Set this project's name.
project("hello_sns")

# Set the C++ standard to use to build this target.
# At least C++ 11 is required for the AWS SDK for C++.
set(CMAKE_CXX_STANDARD 11)

# Use the MSVC variable to determine if this is a Windows build.
set(WINDOWS_BUILD ${MSVC})

if (WINDOWS_BUILD) # Set the location where CMake can find the installed libraries for the AWS SDK.
    string(REPLACE ";" "/aws-cpp-sdk-all;" SYSTEM_MODULE_PATH "${CMAKE_SYSTEM_PREFIX_PATH}/aws-cpp-sdk-all")
    list(APPEND CMAKE_PREFIX_PATH ${SYSTEM_MODULE_PATH})
endif ()

# Find the AWS SDK for C++ package.
find_package(AWSSDK REQUIRED COMPONENTS ${SERVICE_COMPONENTS})

if (WINDOWS_BUILD AND AWSSDK_INSTALL_AS_SHARED_LIBS)
    # Copy relevant AWS SDK for C++ libraries into the current binary directory for running and debugging.

    # set(BIN_SUB_DIR "/Debug") # If you are building from the command line you may need to uncomment this
    # and set the proper subdirectory to the executables' location.

    AWSSDK_CPY_DYN_LIBS(SERVICE_COMPONENTS "" ${CMAKE_CURRENT_BINARY_DIR}${BIN_SUB_DIR})
endif ()

add_executable(${PROJECT_NAME}
        hello_sns.cpp)

target_link_libraries(${PROJECT_NAME}
        ${AWSSDK_LINK_LIBRARIES})
```
Code for the hello\$1sns.cpp source file.  

```
#include <aws/core/Aws.h>
#include <aws/sns/SNSClient.h>
#include <aws/sns/model/ListTopicsRequest.h>
#include <iostream>

/*
 *  A "Hello SNS" starter application which initializes an Amazon Simple Notification
 *  Service (Amazon SNS) client and lists the SNS topics in the current account.
 *
 *  main function
 *
 *  Usage: 'hello_sns'
 *
 */

int main(int argc, char **argv) {
    Aws::SDKOptions options;
    // Optionally change the log level for debugging.
//   options.loggingOptions.logLevel = Utils::Logging::LogLevel::Debug;
    Aws::InitAPI(options); // Should only be called once.
    {
        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

        Aws::SNS::SNSClient snsClient(clientConfig);

        Aws::Vector<Aws::SNS::Model::Topic> allTopics;
        Aws::String nextToken; // Next token is used to handle a paginated response.
        do {
            Aws::SNS::Model::ListTopicsRequest request;

            if (!nextToken.empty()) {
                request.SetNextToken(nextToken);
            }

            const Aws::SNS::Model::ListTopicsOutcome outcome = snsClient.ListTopics(
                    request);

            if (outcome.IsSuccess()) {
                const Aws::Vector<Aws::SNS::Model::Topic> &paginatedTopics =
                        outcome.GetResult().GetTopics();
                if (!paginatedTopics.empty()) {
                    allTopics.insert(allTopics.cend(), paginatedTopics.cbegin(),
                                     paginatedTopics.cend());
                }
            }
            else {
                std::cerr << "Error listing topics " << outcome.GetError().GetMessage()
                          << std::endl;
                return 1;
            }

            nextToken = outcome.GetResult().GetNextToken();
        } while (!nextToken.empty());

        std::cout << "Hello Amazon SNS! You have " << allTopics.size() << " topic"
                  << (allTopics.size() == 1 ? "" : "s") << " in your account."
                  << std::endl;

        if (!allTopics.empty()) {
            std::cout << "Here are your topic ARNs." << std::endl;
            for (const Aws::SNS::Model::Topic &topic: allTopics) {
                std::cout << "  * " << topic.GetTopicArn() << std::endl;
            }
        }
    }


    Aws::ShutdownAPI(options); // Should only be called once.
    return 0;
}
```
+  For API details, see [ListTopics](https://docs.aws.amazon.com/goto/SdkForCpp/sns-2010-03-31/ListTopics) in *AWS SDK for C\$1\$1 API Reference*. 

------
#### [ Go ]

**SDK for Go V2**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/sns#code-examples). 

```
package main

import (
	"context"
	"fmt"
	"log"

	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/sns"
	"github.com/aws/aws-sdk-go-v2/service/sns/types"
)

// main uses the AWS SDK for Go V2 to create an Amazon Simple Notification Service
// (Amazon SNS) client and list the topics in your account.
// This example uses the default settings specified in your shared credentials
// and config files.
func main() {
	ctx := context.Background()
	sdkConfig, err := config.LoadDefaultConfig(ctx)
	if err != nil {
		fmt.Println("Couldn't load default configuration. Have you set up your AWS account?")
		fmt.Println(err)
		return
	}
	snsClient := sns.NewFromConfig(sdkConfig)
	fmt.Println("Let's list the topics for your account.")
	var topics []types.Topic
	paginator := sns.NewListTopicsPaginator(snsClient, &sns.ListTopicsInput{})
	for paginator.HasMorePages() {
		output, err := paginator.NextPage(ctx)
		if err != nil {
			log.Printf("Couldn't get topics. Here's why: %v\n", err)
			break
		} else {
			topics = append(topics, output.Topics...)
		}
	}
	if len(topics) == 0 {
		fmt.Println("You don't have any topics!")
	} else {
		for _, topic := range topics {
			fmt.Printf("\t%v\n", *topic.TopicArn)
		}
	}
}
```
+  For API details, see [ListTopics](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/sns#Client.ListTopics) in *AWS SDK for Go API Reference*. 

------
#### [ Java ]

**SDK for Java 2.x**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/sns#code-examples). 

```
package com.example.sns;

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sns.SnsClient;
import software.amazon.awssdk.services.sns.model.SnsException;
import software.amazon.awssdk.services.sns.paginators.ListTopicsIterable;

public class HelloSNS {
    public static void main(String[] args) {
        SnsClient snsClient = SnsClient.builder()
                .region(Region.US_EAST_1)
                .build();

        listSNSTopics(snsClient);
        snsClient.close();
    }

    public static void listSNSTopics(SnsClient snsClient) {
        try {
            ListTopicsIterable listTopics = snsClient.listTopicsPaginator();
            listTopics.stream()
                    .flatMap(r -> r.topics().stream())
                    .forEach(content -> System.out.println(" Topic ARN: " + content.topicArn()));

        } catch (SnsException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}
```
+  For API details, see [ListTopics](https://docs.aws.amazon.com/goto/SdkForJavaV2/sns-2010-03-31/ListTopics) in *AWS SDK for Java 2.x API Reference*. 

------
#### [ JavaScript ]

**SDK for JavaScript (v3)**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/sns#code-examples). 
Initialize an SNS client and and list topics in your account.  

```
import { SNSClient, paginateListTopics } from "@aws-sdk/client-sns";

export const helloSns = async () => {
  // The configuration object (`{}`) is required. If the region and credentials
  // are omitted, the SDK uses your local configuration if it exists.
  const client = new SNSClient({});

  // You can also use `ListTopicsCommand`, but to use that command you must
  // handle the pagination yourself. You can do that by sending the `ListTopicsCommand`
  // with the `NextToken` parameter from the previous request.
  const paginatedTopics = paginateListTopics({ client }, {});
  const topics = [];

  for await (const page of paginatedTopics) {
    if (page.Topics?.length) {
      topics.push(...page.Topics);
    }
  }

  const suffix = topics.length === 1 ? "" : "s";

  console.log(
    `Hello, Amazon SNS! You have ${topics.length} topic${suffix} in your account.`,
  );
  console.log(topics.map((t) => `  * ${t.TopicArn}`).join("\n"));
};
```
+  For API details, see [ListTopics](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/sns/command/ListTopicsCommand) in *AWS SDK for JavaScript API Reference*. 

------
#### [ Kotlin ]

**SDK for Kotlin**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/kotlin/services/sns#code-examples). 

```
import aws.sdk.kotlin.services.sns.SnsClient
import aws.sdk.kotlin.services.sns.model.ListTopicsRequest
import aws.sdk.kotlin.services.sns.paginators.listTopicsPaginated
import kotlinx.coroutines.flow.transform

/**
Before running this Kotlin 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-kotlin/latest/developer-guide/setup.html
 */
suspend fun main() {
    listTopicsPag()
}

suspend fun listTopicsPag() {
    SnsClient.fromEnvironment { region = "us-east-1" }.use { snsClient ->
        snsClient
            .listTopicsPaginated(ListTopicsRequest { })
            .transform { it.topics?.forEach { topic -> emit(topic) } }
            .collect { topic ->
                println("The topic ARN is ${topic.topicArn}")
            }
    }
}
```
+  For API details, see [ListTopics](https://sdk.amazonaws.com/kotlin/api/latest/index.html) in *AWS SDK for Kotlin API reference*. 

------
#### [ Swift ]

**SDK for Swift**  
 There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/swift/example_code/sns/basics#code-examples). 
The Package.swift file.  

```
import PackageDescription

let package = Package(
    name: "sns-basics",
    // Let Xcode know the minimum Apple platforms supported.
    platforms: [
        .macOS(.v13),
        .iOS(.v15)
    ],
    dependencies: [
        // Dependencies declare other packages that this package depends on.
        .package(
            url: "https://github.com/awslabs/aws-sdk-swift",
            from: "1.0.0"),
        .package(
            url: "https://github.com/apple/swift-argument-parser.git",
            branch: "main"
        )
    ],
    targets: [
        // Targets are the basic building blocks of a package, defining a module or a test suite.
        // Targets can depend on other targets in this package and products
        // from dependencies.
        .executableTarget(
            name: "sns-basics",
            dependencies: [
                .product(name: "AWSSNS", package: "aws-sdk-swift"),
                .product(name: "ArgumentParser", package: "swift-argument-parser")
            ],
            path: "Sources")

    ]
)
```
The main Swift program.  

```
import ArgumentParser
import AWSClientRuntime
import AWSSNS
import Foundation

struct ExampleCommand: ParsableCommand {
    @Option(help: "Name of the Amazon Region to use (default: us-east-1)")
    var region = "us-east-1"

    static var configuration = CommandConfiguration(
        commandName: "sns-basics",
        abstract: """
        This example shows how to list all of your available Amazon SNS topics.
        """,
        discussion: """
        """
    )
    
    /// Called by ``main()`` to run the bulk of the example.
    func runAsync() async throws {
        let config = try await SNSClient.SNSClientConfiguration(region: region)
        let snsClient = SNSClient(config: config)

        var topics: [String] = []
        let outputPages = snsClient.listTopicsPaginated(
            input: ListTopicsInput()
        )

        // Each time a page of results arrives, process its contents.

        for try await output in outputPages {
            guard let topicList = output.topics else {
                print("Unable to get a page of Amazon SNS topics.")
                return
            }

            // Iterate over the topics listed on this page, adding their ARNs
            // to the `topics` array.

            for topic in topicList {
                guard let arn = topic.topicArn else {
                    print("Topic has no ARN.")
                    return
                }
                topics.append(arn)
            }
        }

        print("You have \(topics.count) topics:")
        for topic in topics {
            print("   \(topic)")
        }
    }
}

/// The program's asynchronous entry point.
@main
struct Main {
    static func main() async {
        let args = Array(CommandLine.arguments.dropFirst())

        do {
            let command = try ExampleCommand.parse(args)
            try await command.runAsync()
        } catch {
            ExampleCommand.exit(withError: error)
        }
    }    
}
```
+  For API details, see [ListTopics](https://sdk.amazonaws.com/swift/api/awssns/latest/documentation/awssns/snsclient/listtopics(input:)) in *AWS SDK for Swift API reference*. 

------

For a complete list of AWS SDK developer guides and code examples, see [Using Amazon SNS with an AWS SDK](sdk-general-information-section.md). This topic also includes information about getting started and details about previous SDK versions.