Amazon SNS examples using SDK for C++

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)
    # 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_sns.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;
}

//! Create an Amazon Simple Notification Service (Amazon SNS) topic.
/*!
  \param topicName: An Amazon SNS topic name.
  \param topicARNResult: String to return the Amazon Resource Name (ARN) for the topic.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::createTopic(const Aws::String &topicName,
                              Aws::String &topicARNResult,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::CreateTopicRequest request;
    request.SetName(topicName);

    const Aws::SNS::Model::CreateTopicOutcome outcome = snsClient.CreateTopic(request);

    if (outcome.IsSuccess()) {
        topicARNResult = outcome.GetResult().GetTopicArn();
        std::cout << "Successfully created an Amazon SNS topic " << topicName
                  << " with topic ARN '" << topicARNResult
                  << "'." << std::endl;

    }
    else {
        std::cerr << "Error creating topic " << topicName << ":" <<
                  outcome.GetError().GetMessage() << std::endl;
        topicARNResult.clear();
    }

    return outcome.IsSuccess();
}

//! Delete an Amazon Simple Notification Service (Amazon SNS) topic.
/*!
  \param topicARN: The Amazon Resource Name (ARN) for an Amazon SNS topic.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::deleteTopic(const Aws::String &topicARN,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::DeleteTopicRequest request;
    request.SetTopicArn(topicARN);

    const Aws::SNS::Model::DeleteTopicOutcome outcome = snsClient.DeleteTopic(request);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted the Amazon SNS topic " << topicARN << std::endl;
    }
    else {
        std::cerr << "Error deleting topic " << topicARN << ":" <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Retrieve the default settings for sending SMS messages from your AWS account by using
//! Amazon Simple Notification Service (Amazon SNS).
/*!
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool
AwsDoc::SNS::getSMSType(const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

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

    const Aws::SNS::Model::GetSMSAttributesOutcome outcome = snsClient.GetSMSAttributes(
            request);

    if (outcome.IsSuccess()) {
        const Aws::Map<Aws::String, Aws::String> attributes =
                outcome.GetResult().GetAttributes();
        if (!attributes.empty()) {
            for (auto const &att: attributes) {
                std::cout << att.first << ":  " << att.second << std::endl;
            }
        }
        else {
            std::cout
                    << "AwsDoc::SNS::getSMSType - an empty map of attributes was retrieved."
                    << std::endl;
        }
    }
    else {
        std::cerr << "Error while getting SMS Type: '"
                  << outcome.GetError().GetMessage()
                  << "'" << std::endl;
    }

    return outcome.IsSuccess();
}

//! Retrieve the properties of an Amazon Simple Notification Service (Amazon SNS) topic.
/*!
  \param topicARN: The Amazon Resource Name (ARN) for an Amazon SNS topic.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::getTopicAttributes(const Aws::String &topicARN,
                                     const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);
    Aws::SNS::Model::GetTopicAttributesRequest request;
    request.SetTopicArn(topicARN);

    const Aws::SNS::Model::GetTopicAttributesOutcome outcome = snsClient.GetTopicAttributes(
            request);

    if (outcome.IsSuccess()) {
        std::cout << "Topic Attributes:" << std::endl;
        for (auto const &attribute: outcome.GetResult().GetAttributes()) {
            std::cout << "  * " << attribute.first << " : " << attribute.second
                      << std::endl;
        }
    }
    else {
        std::cerr << "Error while getting Topic attributes "
                  << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

//! Retrieve a list of Amazon Simple Notification Service (Amazon SNS) subscriptions.
/*!
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::listSubscriptions(
        const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::String nextToken; // Next token is used to handle a paginated response.
    bool result = true;
    Aws::Vector<Aws::SNS::Model::Subscription> subscriptions;
    do {
        Aws::SNS::Model::ListSubscriptionsRequest request;

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

        const Aws::SNS::Model::ListSubscriptionsOutcome outcome = snsClient.ListSubscriptions(
                request);

        if (outcome.IsSuccess()) {
            const Aws::Vector<Aws::SNS::Model::Subscription> &newSubscriptions =
                    outcome.GetResult().GetSubscriptions();
            subscriptions.insert(subscriptions.cend(), newSubscriptions.begin(),
                                 newSubscriptions.end());
        }
        else {
            std::cerr << "Error listing subscriptions "
                      << outcome.GetError().GetMessage()
                      <<
                      std::endl;
            result = false;
            break;
        }

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

    if (result) {
        if (subscriptions.empty()) {
            std::cout << "No subscriptions found" << std::endl;
        }
        else {
            std::cout << "Subscriptions list:" << std::endl;
            for (auto const &subscription: subscriptions) {
                std::cout << "  * " << subscription.GetSubscriptionArn() << std::endl;
            }
        }
    }
    return result;
}

//! Retrieve a list of Amazon Simple Notification Service (Amazon SNS) topics.
/*!
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool
AwsDoc::SNS::listTopics(const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::String nextToken; // Next token is used to handle a paginated response.
    bool result = true;
    do {
        Aws::SNS::Model::ListTopicsRequest request;

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

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

        if (outcome.IsSuccess()) {
            std::cout << "Topics list:" << std::endl;
            for (auto const &topic: outcome.GetResult().GetTopics()) {
                std::cout << "  * " << topic.GetTopicArn() << std::endl;
            }
        }
        else {
            std::cerr << "Error listing topics " << outcome.GetError().GetMessage() <<
                      std::endl;
            result = false;
            break;
        }

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

    return result;
}

//! Send a message to an Amazon Simple Notification Service (Amazon SNS) topic.
/*!
  \param message: The message to publish.
  \param topicARN: The Amazon Resource Name (ARN) for an Amazon SNS topic.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::publishToTopic(const Aws::String &message,
                                 const Aws::String &topicARN,
                                 const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::PublishRequest request;
    request.SetMessage(message);
    request.SetTopicArn(topicARN);

    const Aws::SNS::Model::PublishOutcome outcome = snsClient.Publish(request);

    if (outcome.IsSuccess()) {
        std::cout << "Message published successfully with id '"
                  << outcome.GetResult().GetMessageId() << "'." << std::endl;
    }
    else {
        std::cerr << "Error while publishing message "
                  << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

Publish a message with an attribute.

        static const Aws::String TONE_ATTRIBUTE("tone");
        static const Aws::Vector<Aws::String> TONES = {"cheerful", "funny", "serious",
                                                       "sincere"};

        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

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

        Aws::SNS::Model::PublishRequest request;
        request.SetTopicArn(topicARN);
        Aws::String message = askQuestion("Enter a message text to publish.  ");
        request.SetMessage(message);

        if (filteringMessages && askYesNoQuestion(
                "Add an attribute to this message? (y/n) ")) {
            for (size_t i = 0; i < TONES.size(); ++i) {
                std::cout << "  " << (i + 1) << ". " << TONES[i] << std::endl;
            }
            int selection = askQuestionForIntRange(
                    "Enter a number for an attribute. ",
                    1, static_cast<int>(TONES.size()));
            Aws::SNS::Model::MessageAttributeValue messageAttributeValue;
            messageAttributeValue.SetDataType("String");
            messageAttributeValue.SetStringValue(TONES[selection - 1]);
            request.AddMessageAttributes(TONE_ATTRIBUTE, messageAttributeValue);
        }

        Aws::SNS::Model::PublishOutcome outcome = snsClient.Publish(request);

        if (outcome.IsSuccess()) {
            std::cout << "Your message was successfully published." << std::endl;
        }
        else {
            std::cerr << "Error with TopicsAndQueues::Publish. "
                      << outcome.GetError().GetMessage()
                      << std::endl;

            cleanUp(topicARN,
                    queueURLS,
                    subscriptionARNS,
                    snsClient,
                    sqsClient);

            return false;
        }

How to use Amazon SNS to set the DefaultSMSType attribute.

//! Set the default settings for sending SMS messages.
/*!
  \param smsType: The type of SMS message that you will send by default.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::setSMSType(const Aws::String &smsType,
                             const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::SetSMSAttributesRequest request;
    request.AddAttributes("DefaultSMSType", smsType);

    const Aws::SNS::Model::SetSMSAttributesOutcome outcome = snsClient.SetSMSAttributes(
            request);

    if (outcome.IsSuccess()) {
        std::cout << "SMS Type set successfully " << std::endl;
    }
    else {
        std::cerr << "Error while setting SMS Type: '"
                  << outcome.GetError().GetMessage()
                  << "'" << std::endl;
    }

    return outcome.IsSuccess();
}

Subscribe an email address to a topic.

//! Subscribe to an Amazon Simple Notification Service (Amazon SNS) topic with delivery to an email address.
/*!
  \param topicARN: An SNS topic Amazon Resource Name (ARN).
  \param emailAddress: An email address.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::subscribeEmail(const Aws::String &topicARN,
                                 const Aws::String &emailAddress,
                                 const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::SubscribeRequest request;
    request.SetTopicArn(topicARN);
    request.SetProtocol("email");
    request.SetEndpoint(emailAddress);

    const Aws::SNS::Model::SubscribeOutcome outcome = snsClient.Subscribe(request);

    if (outcome.IsSuccess()) {
        std::cout << "Subscribed successfully." << std::endl;
        std::cout << "Subscription ARN '" << outcome.GetResult().GetSubscriptionArn()
                  << "'." << std::endl;
    }
    else {
        std::cerr << "Error while subscribing " << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

Subscribe a mobile application to a topic.

//! Subscribe to an Amazon Simple Notification Service (Amazon SNS) topic with delivery to a mobile app.
/*!
  \param topicARN: The Amazon Resource Name (ARN) for an Amazon SNS topic.
  \param endpointARN: The ARN for a mobile app or device endpoint.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool
AwsDoc::SNS::subscribeApp(const Aws::String &topicARN,
                          const Aws::String &endpointARN,
                          const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::SubscribeRequest request;
    request.SetTopicArn(topicARN);
    request.SetProtocol("application");
    request.SetEndpoint(endpointARN);

    const Aws::SNS::Model::SubscribeOutcome outcome = snsClient.Subscribe(request);

    if (outcome.IsSuccess()) {
        std::cout << "Subscribed successfully." << std::endl;
        std::cout << "Subscription ARN '" << outcome.GetResult().GetSubscriptionArn()
                  << "'." << std::endl;
    }
    else {
        std::cerr << "Error while subscribing " << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

Subscribe a Lambda function to a topic.

//! Subscribe to an Amazon Simple Notification Service (Amazon SNS) topic with delivery to an AWS Lambda function.
/*!
  \param topicARN: The Amazon Resource Name (ARN) for an Amazon SNS topic.
  \param lambdaFunctionARN: The ARN for an AWS Lambda function.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::subscribeLambda(const Aws::String &topicARN,
                                  const Aws::String &lambdaFunctionARN,
                                  const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::SubscribeRequest request;
    request.SetTopicArn(topicARN);
    request.SetProtocol("lambda");
    request.SetEndpoint(lambdaFunctionARN);

    const Aws::SNS::Model::SubscribeOutcome outcome = snsClient.Subscribe(request);

    if (outcome.IsSuccess()) {
        std::cout << "Subscribed successfully." << std::endl;
        std::cout << "Subscription ARN '" << outcome.GetResult().GetSubscriptionArn()
                  << "'." << std::endl;
    }
    else {
        std::cerr << "Error while subscribing " << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

Subscribe an SQS queue to a topic.

        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

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

            Aws::SNS::Model::SubscribeRequest request;
            request.SetTopicArn(topicARN);
            request.SetProtocol("sqs");
            request.SetEndpoint(queueARN);

            Aws::SNS::Model::SubscribeOutcome outcome = snsClient.Subscribe(request);

            if (outcome.IsSuccess()) {
                Aws::String subscriptionARN = outcome.GetResult().GetSubscriptionArn();
                std::cout << "The queue '" << queueName
                          << "' has been subscribed to the topic '"
                          << "'" << topicName << "'" << std::endl;
                std::cout << "with the subscription ARN '" << subscriptionARN << "."
                          << std::endl;
                subscriptionARNS.push_back(subscriptionARN);
            }
            else {
                std::cerr << "Error with TopicsAndQueues::Subscribe. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }

Subscribe with a filter to a topic.

        static const Aws::String TONE_ATTRIBUTE("tone");
        static const Aws::Vector<Aws::String> TONES = {"cheerful", "funny", "serious",
                                                       "sincere"};

        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

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

            Aws::SNS::Model::SubscribeRequest request;
            request.SetTopicArn(topicARN);
            request.SetProtocol("sqs");
            request.SetEndpoint(queueARN);
            if (isFifoTopic) {
                if (first) {
                    std::cout << "Subscriptions to a FIFO topic can have filters."
                              << std::endl;
                    std::cout
                            << "If you add a filter to this subscription, then only the filtered messages "
                            << "will be received in the queue." << std::endl;
                    std::cout << "For information about message filtering, "
                              << "see https://docs.aws.amazon.com/sns/latest/dg/sns-message-filtering.html"
                              << std::endl;
                    std::cout << "For this example, you can filter messages by a \""
                              << TONE_ATTRIBUTE << "\" attribute." << std::endl;
                }

                std::ostringstream ostringstream;
                ostringstream << "Filter messages for \"" << queueName
                              << "\"'s subscription to the topic \""
                              << topicName << "\"?  (y/n)";

                // Add filter if user answers yes.
                if (askYesNoQuestion(ostringstream.str())) {
                    Aws::String jsonPolicy = getFilterPolicyFromUser();
                    if (!jsonPolicy.empty()) {
                        filteringMessages = true;

                        std::cout << "This is the filter policy for this subscription."
                                  << std::endl;
                        std::cout << jsonPolicy << std::endl;

                        request.AddAttributes("FilterPolicy", jsonPolicy);
                    }
                    else {
                        std::cout
                                << "Because you did not select any attributes, no filter "
                                << "will be added to this subscription." << std::endl;
                    }
                }
            }  // if (isFifoTopic)
            Aws::SNS::Model::SubscribeOutcome outcome = snsClient.Subscribe(request);

            if (outcome.IsSuccess()) {
                Aws::String subscriptionARN = outcome.GetResult().GetSubscriptionArn();
                std::cout << "The queue '" << queueName
                          << "' has been subscribed to the topic '"
                          << "'" << topicName << "'" << std::endl;
                std::cout << "with the subscription ARN '" << subscriptionARN << "."
                          << std::endl;
                subscriptionARNS.push_back(subscriptionARN);
            }
            else {
                std::cerr << "Error with TopicsAndQueues::Subscribe. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }

//! Routine that lets the user select attributes for a subscription filter policy.
/*!
 \sa getFilterPolicyFromUser()
 \return Aws::String: The filter policy as JSON.
 */
Aws::String AwsDoc::TopicsAndQueues::getFilterPolicyFromUser() {
    std::cout
            << "You can filter messages by one or more of the following \""
            << TONE_ATTRIBUTE << "\" attributes." << std::endl;

    std::vector<Aws::String> filterSelections;
    int selection;
    do {
        for (size_t j = 0; j < TONES.size(); ++j) {
            std::cout << "  " << (j + 1) << ". " << TONES[j]
                      << std::endl;
        }
        selection = askQuestionForIntRange(
                "Enter a number (or enter zero to stop adding more). ",
                0, static_cast<int>(TONES.size()));

        if (selection != 0) {
            const Aws::String &selectedTone(TONES[selection - 1]);
            // Add the tone to the selection if it is not already added.
            if (std::find(filterSelections.begin(),
                          filterSelections.end(),
                          selectedTone)
                == filterSelections.end()) {
                filterSelections.push_back(selectedTone);
            }
        }
    } while (selection != 0);

    Aws::String result;
    if (!filterSelections.empty()) {
        std::ostringstream jsonPolicyStream;
        jsonPolicyStream << "{ \"" << TONE_ATTRIBUTE << "\": [";


        for (size_t j = 0; j < filterSelections.size(); ++j) {
            jsonPolicyStream << "\"" << filterSelections[j] << "\"";
            if (j < filterSelections.size() - 1) {
                jsonPolicyStream << ",";
            }
        }
        jsonPolicyStream << "] }";

        result = jsonPolicyStream.str();
    }

    return result;
}

//! Delete a subscription to an Amazon Simple Notification Service (Amazon SNS) topic.
/*!
  \param subscriptionARN: The Amazon Resource Name (ARN) for an Amazon SNS topic subscription.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::unsubscribe(const Aws::String &subscriptionARN,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::UnsubscribeRequest request;
    request.SetSubscriptionArn(subscriptionARN);

    const Aws::SNS::Model::UnsubscribeOutcome outcome = snsClient.Unsubscribe(request);

    if (outcome.IsSuccess()) {
        std::cout << "Unsubscribed successfully " << std::endl;
    }
    else {
        std::cerr << "Error while unsubscribing " << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

/**
 * Publish SMS: use Amazon Simple Notification Service (Amazon SNS) to send an SMS text message to a phone number.
 * Note: This requires additional AWS configuration prior to running example. 
 * 
 *  NOTE: When you start using Amazon SNS to send SMS messages, your AWS account is in the SMS sandbox and you can only
 *  use verified destination phone numbers. See https://docs.aws.amazon.com/sns/latest/dg/sns-sms-sandbox.html.
 *  NOTE: If destination is in the US, you also have an additional restriction that you have use a dedicated
 *  origination ID (phone number). You can request an origination number using Amazon Pinpoint for a fee.
 *  See https://aws.amazon.com/blogs/compute/provisioning-and-using-10dlc-origination-numbers-with-amazon-sns/ 
 *  for more information. 
 * 
 *  <phone_number_value> input parameter uses E.164 format. 
 *  For example, in United States, this input value should be of the form: +12223334444
 */

//! Send an SMS text message to a phone number.
/*!
  \param message: The message to publish.
  \param phoneNumber: The phone number of the recipient in E.164 format.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::SNS::publishSms(const Aws::String &message,
                             const Aws::String &phoneNumber,
                             const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::SNS::SNSClient snsClient(clientConfiguration);

    Aws::SNS::Model::PublishRequest request;
    request.SetMessage(message);
    request.SetPhoneNumber(phoneNumber);

    const Aws::SNS::Model::PublishOutcome outcome = snsClient.Publish(request);

    if (outcome.IsSuccess()) {
        std::cout << "Message published successfully with message id, '"
                  << outcome.GetResult().GetMessageId() << "'."
                  << std::endl;
    }
    else {
        std::cerr << "Error while publishing message "
                  << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

        Aws::Client::ClientConfiguration clientConfig;
        // Optional: Set to the AWS Region (overrides config file).
        // clientConfig.region = "us-east-1";

//! Workflow for messaging with topics and queues using Amazon SNS and Amazon SQS.
/*!
 \param clientConfig Aws client configuration.
 \return bool: Successful completion.
 */
bool AwsDoc::TopicsAndQueues::messagingWithTopicsAndQueues(
        const Aws::Client::ClientConfiguration &clientConfiguration) {
    std::cout << "Welcome to messaging with topics and queues." << std::endl;
    printAsterisksLine();
    std::cout << "In this workflow, you will create an SNS topic and subscribe "
              << NUMBER_OF_QUEUES <<
              " SQS queues to the topic." << std::endl;
    std::cout
            << "You can select from several options for configuring the topic and the subscriptions for the "
            << NUMBER_OF_QUEUES << " queues." << std::endl;
    std::cout << "You can then post to the topic and see the results in the queues."
              << std::endl;

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

    printAsterisksLine();

    std::cout << "SNS topics can be configured as FIFO (First-In-First-Out)."
              << std::endl;
    std::cout
            << "FIFO topics deliver messages in order and support deduplication and message filtering."
            << std::endl;
    bool isFifoTopic = askYesNoQuestion(
            "Would you like to work with FIFO topics? (y/n) ");

    bool contentBasedDeduplication = false;
    Aws::String topicName;
    if (isFifoTopic) {
        printAsterisksLine();
        std::cout << "Because you have chosen a FIFO topic, deduplication is supported."
                  << std::endl;
        std::cout
                << "Deduplication IDs are either set in the message or automatically generated "
                << "from content using a hash function." << std::endl;
        std::cout
                << "If a message is successfully published to an SNS FIFO topic, any message "
                << "published and determined to have the same deduplication ID, "
                << std::endl;
        std::cout
                << "within the five-minute deduplication interval, is accepted but not delivered."
                << std::endl;
        std::cout
                << "For more information about deduplication, "
                << "see https://docs.aws.amazon.com/sns/latest/dg/fifo-message-dedup.html."
                << std::endl;
        contentBasedDeduplication = askYesNoQuestion(
                "Use content-based deduplication instead of entering a deduplication ID? (y/n) ");
    }

    printAsterisksLine();

    Aws::SQS::SQSClient sqsClient(clientConfiguration);
    Aws::Vector<Aws::String> queueURLS;
    Aws::Vector<Aws::String> subscriptionARNS;

    Aws::String topicARN;
    {
        topicName = askQuestion("Enter a name for your SNS topic. ");

        // 1.  Create an Amazon SNS topic, either FIFO or non-FIFO.
        Aws::SNS::Model::CreateTopicRequest request;

        if (isFifoTopic) {
            request.AddAttributes("FifoTopic", "true");
            if (contentBasedDeduplication) {
                request.AddAttributes("ContentBasedDeduplication", "true");
            }
            topicName = topicName + FIFO_SUFFIX;

            std::cout
                    << "Because you have selected a FIFO topic, '.fifo' must be appended to the topic name."
                    << std::endl;
        }

        request.SetName(topicName);

        Aws::SNS::Model::CreateTopicOutcome outcome = snsClient.CreateTopic(request);

        if (outcome.IsSuccess()) {
            topicARN = outcome.GetResult().GetTopicArn();
            std::cout << "Your new topic with the name '" << topicName
                      << "' and the topic Amazon Resource Name (ARN) " << std::endl;
            std::cout << "'" << topicARN << "' has been created." << std::endl;

        }
        else {
            std::cerr << "Error with TopicsAndQueues::CreateTopic. "
                      << outcome.GetError().GetMessage()
                      << std::endl;

            cleanUp(topicARN,
                    queueURLS,
                    subscriptionARNS,
                    snsClient,
                    sqsClient);

            return false;
        }
    }

    printAsterisksLine();

    std::cout << "Now you will create " << NUMBER_OF_QUEUES
              << " SQS queues to subscribe to the topic." << std::endl;
    Aws::Vector<Aws::String> queueNames;
    bool filteringMessages = false;
    bool first = true;
    for (int i = 1; i <= NUMBER_OF_QUEUES; ++i) {
        Aws::String queueURL;
        Aws::String queueName;
        {
            printAsterisksLine();
            std::ostringstream ostringstream;
            ostringstream << "Enter a name for " << (first ? "an" : "the next")
                          << " SQS queue. ";
            queueName = askQuestion(ostringstream.str());

            // 2.  Create an SQS queue.
            Aws::SQS::Model::CreateQueueRequest request;
            if (isFifoTopic) {
                request.AddAttributes(Aws::SQS::Model::QueueAttributeName::FifoQueue,
                                      "true");
                queueName = queueName + FIFO_SUFFIX;

                if (first) // Only explain this once.
                {
                    std::cout
                            << "Because you are creating a FIFO SQS queue, '.fifo' must "
                            << "be appended to the queue name." << std::endl;
                }
            }

            request.SetQueueName(queueName);
            queueNames.push_back(queueName);

            Aws::SQS::Model::CreateQueueOutcome outcome =
                    sqsClient.CreateQueue(request);

            if (outcome.IsSuccess()) {
                queueURL = outcome.GetResult().GetQueueUrl();
                std::cout << "Your new SQS queue with the name '" << queueName
                          << "' and the queue URL " << std::endl;
                std::cout << "'" << queueURL << "' has been created." << std::endl;
            }
            else {
                std::cerr << "Error with SQS::CreateQueue. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }
        }
        queueURLS.push_back(queueURL);

        if (first) // Only explain this once.
        {
            std::cout
                    << "The queue URL is used to retrieve the queue ARN, which is "
                    << "used to create a subscription." << std::endl;
        }

        Aws::String queueARN;
        {
            // 3.  Get the SQS queue ARN attribute.
            Aws::SQS::Model::GetQueueAttributesRequest request;
            request.SetQueueUrl(queueURL);
            request.AddAttributeNames(Aws::SQS::Model::QueueAttributeName::QueueArn);

            Aws::SQS::Model::GetQueueAttributesOutcome outcome =
                    sqsClient.GetQueueAttributes(request);

            if (outcome.IsSuccess()) {
                const Aws::Map<Aws::SQS::Model::QueueAttributeName, Aws::String> &attributes =
                        outcome.GetResult().GetAttributes();
                const auto &iter = attributes.find(
                        Aws::SQS::Model::QueueAttributeName::QueueArn);
                if (iter != attributes.end()) {
                    queueARN = iter->second;
                    std::cout << "The queue ARN '" << queueARN
                              << "' has been retrieved."
                              << std::endl;
                }
                else {
                    std::cerr
                            << "Error ARN attribute not returned by GetQueueAttribute."
                            << std::endl;

                    cleanUp(topicARN,
                            queueURLS,
                            subscriptionARNS,
                            snsClient,
                            sqsClient);

                    return false;
                }
            }
            else {
                std::cerr << "Error with SQS::GetQueueAttributes. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }
        }

        if (first) {
            std::cout
                    << "An IAM policy must be attached to an SQS queue, enabling it to receive "
                       "messages from an SNS topic." << std::endl;
        }

        {
            // 4.  Set the SQS queue policy attribute with a policy enabling the receipt of SNS messages.
            Aws::SQS::Model::SetQueueAttributesRequest request;
            request.SetQueueUrl(queueURL);
            Aws::String policy = createPolicyForQueue(queueARN, topicARN);
            request.AddAttributes(Aws::SQS::Model::QueueAttributeName::Policy,
                                  policy);

            Aws::SQS::Model::SetQueueAttributesOutcome outcome =
                    sqsClient.SetQueueAttributes(request);

            if (outcome.IsSuccess()) {
                std::cout << "The attributes for the queue '" << queueName
                          << "' were successfully updated." << std::endl;
            }
            else {
                std::cerr << "Error with SQS::SetQueueAttributes. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }
        }

        printAsterisksLine();

        {
            // 5.  Subscribe the SQS queue to the SNS topic.
            Aws::SNS::Model::SubscribeRequest request;
            request.SetTopicArn(topicARN);
            request.SetProtocol("sqs");
            request.SetEndpoint(queueARN);
            if (isFifoTopic) {
                if (first) {
                    std::cout << "Subscriptions to a FIFO topic can have filters."
                              << std::endl;
                    std::cout
                            << "If you add a filter to this subscription, then only the filtered messages "
                            << "will be received in the queue." << std::endl;
                    std::cout << "For information about message filtering, "
                              << "see https://docs.aws.amazon.com/sns/latest/dg/sns-message-filtering.html"
                              << std::endl;
                    std::cout << "For this example, you can filter messages by a \""
                              << TONE_ATTRIBUTE << "\" attribute." << std::endl;
                }

                std::ostringstream ostringstream;
                ostringstream << "Filter messages for \"" << queueName
                              << "\"'s subscription to the topic \""
                              << topicName << "\"?  (y/n)";

                // Add filter if user answers yes.
                if (askYesNoQuestion(ostringstream.str())) {
                    Aws::String jsonPolicy = getFilterPolicyFromUser();
                    if (!jsonPolicy.empty()) {
                        filteringMessages = true;

                        std::cout << "This is the filter policy for this subscription."
                                  << std::endl;
                        std::cout << jsonPolicy << std::endl;

                        request.AddAttributes("FilterPolicy", jsonPolicy);
                    }
                    else {
                        std::cout
                                << "Because you did not select any attributes, no filter "
                                << "will be added to this subscription." << std::endl;
                    }
                }
            }  // if (isFifoTopic)
            Aws::SNS::Model::SubscribeOutcome outcome = snsClient.Subscribe(request);

            if (outcome.IsSuccess()) {
                Aws::String subscriptionARN = outcome.GetResult().GetSubscriptionArn();
                std::cout << "The queue '" << queueName
                          << "' has been subscribed to the topic '"
                          << "'" << topicName << "'" << std::endl;
                std::cout << "with the subscription ARN '" << subscriptionARN << "."
                          << std::endl;
                subscriptionARNS.push_back(subscriptionARN);
            }
            else {
                std::cerr << "Error with TopicsAndQueues::Subscribe. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }
        }

        first = false;
    }

    first = true;
    do {
        printAsterisksLine();

        // 6.  Publish a message to the SNS topic.
        Aws::SNS::Model::PublishRequest request;
        request.SetTopicArn(topicARN);
        Aws::String message = askQuestion("Enter a message text to publish.  ");
        request.SetMessage(message);
        if (isFifoTopic) {
            if (first) {
                std::cout
                        << "Because you are using a FIFO topic, you must set a message group ID."
                        << std::endl;
                std::cout
                        << "All messages within the same group will be received in the "
                        << "order they were published." << std::endl;
            }
            Aws::String messageGroupID = askQuestion(
                    "Enter a message group ID for this message. ");
            request.SetMessageGroupId(messageGroupID);
            if (!contentBasedDeduplication) {
                if (first) {
                    std::cout
                            << "Because you are not using content-based deduplication, "
                            << "you must enter a deduplication ID." << std::endl;
                }
                Aws::String deduplicationID = askQuestion(
                        "Enter a deduplication ID for this message. ");
                request.SetMessageDeduplicationId(deduplicationID);
            }
        }

        if (filteringMessages && askYesNoQuestion(
                "Add an attribute to this message? (y/n) ")) {
            for (size_t i = 0; i < TONES.size(); ++i) {
                std::cout << "  " << (i + 1) << ". " << TONES[i] << std::endl;
            }
            int selection = askQuestionForIntRange(
                    "Enter a number for an attribute. ",
                    1, static_cast<int>(TONES.size()));
            Aws::SNS::Model::MessageAttributeValue messageAttributeValue;
            messageAttributeValue.SetDataType("String");
            messageAttributeValue.SetStringValue(TONES[selection - 1]);
            request.AddMessageAttributes(TONE_ATTRIBUTE, messageAttributeValue);
        }

        Aws::SNS::Model::PublishOutcome outcome = snsClient.Publish(request);

        if (outcome.IsSuccess()) {
            std::cout << "Your message was successfully published." << std::endl;
        }
        else {
            std::cerr << "Error with TopicsAndQueues::Publish. "
                      << outcome.GetError().GetMessage()
                      << std::endl;

            cleanUp(topicARN,
                    queueURLS,
                    subscriptionARNS,
                    snsClient,
                    sqsClient);

            return false;
        }

        first = false;
    } while (askYesNoQuestion("Post another message? (y/n) "));

    printAsterisksLine();

    std::cout << "Now the SQS queue will be polled to retrieve the messages."
              << std::endl;
    askQuestion("Press any key to continue...", alwaysTrueTest);

    for (size_t i = 0; i < queueURLS.size(); ++i) {
        // 7.  Poll an SQS queue for its messages.
        std::vector<Aws::String> messages;
        std::vector<Aws::String> receiptHandles;
        while (true) {
            Aws::SQS::Model::ReceiveMessageRequest request;
            request.SetMaxNumberOfMessages(10);
            request.SetQueueUrl(queueURLS[i]);

            // Setting WaitTimeSeconds to non-zero enables long polling.
            // For information about long polling, see
            // https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-short-and-long-polling.html
            request.SetWaitTimeSeconds(1);
            Aws::SQS::Model::ReceiveMessageOutcome outcome =
                    sqsClient.ReceiveMessage(request);

            if (outcome.IsSuccess()) {
                const Aws::Vector<Aws::SQS::Model::Message> &newMessages = outcome.GetResult().GetMessages();
                if (newMessages.empty()) {
                    break;
                }
                else {
                    for (const Aws::SQS::Model::Message &message: newMessages) {
                        messages.push_back(message.GetBody());
                        receiptHandles.push_back(message.GetReceiptHandle());
                    }
                }
            }
            else {
                std::cerr << "Error with SQS::ReceiveMessage. "
                          << outcome.GetError().GetMessage()
                          << std::endl;

                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }
        }

        printAsterisksLine();

        if (messages.empty()) {
            std::cout << "No messages were ";
        }
        else if (messages.size() == 1) {
            std::cout << "One message was ";
        }
        else {
            std::cout << messages.size() << " messages were ";
        }
        std::cout << "received by the queue '" << queueNames[i]
                  << "'." << std::endl;
        for (const Aws::String &message: messages) {
            std::cout << "  Message : '" << message << "'."
                      << std::endl;
        }

        // 8.  Delete a batch of messages from an SQS queue.
        if (!receiptHandles.empty()) {
            Aws::SQS::Model::DeleteMessageBatchRequest request;
            request.SetQueueUrl(queueURLS[i]);
            int id = 1; // Ids must be unique within a batch delete request.
            for (const Aws::String &receiptHandle: receiptHandles) {
                Aws::SQS::Model::DeleteMessageBatchRequestEntry entry;
                entry.SetId(std::to_string(id));
                ++id;
                entry.SetReceiptHandle(receiptHandle);
                request.AddEntries(entry);
            }

            Aws::SQS::Model::DeleteMessageBatchOutcome outcome =
                    sqsClient.DeleteMessageBatch(request);

            if (outcome.IsSuccess()) {
                std::cout << "The batch deletion of messages was successful."
                          << std::endl;
            }
            else {
                std::cerr << "Error with SQS::DeleteMessageBatch. "
                          << outcome.GetError().GetMessage()
                          << std::endl;
                cleanUp(topicARN,
                        queueURLS,
                        subscriptionARNS,
                        snsClient,
                        sqsClient);

                return false;
            }
        }
    }

    return cleanUp(topicARN,
                   queueURLS,
                   subscriptionARNS,
                   snsClient,
                   sqsClient,
                   true); // askUser
}


bool AwsDoc::TopicsAndQueues::cleanUp(const Aws::String &topicARN,
                                      const Aws::Vector<Aws::String> &queueURLS,
                                      const Aws::Vector<Aws::String> &subscriptionARNS,
                                      const Aws::SNS::SNSClient &snsClient,
                                      const Aws::SQS::SQSClient &sqsClient,
                                      bool askUser) {
    bool result = true;
    printAsterisksLine();
    if (!queueURLS.empty() && askUser &&
        askYesNoQuestion("Delete the SQS queues? (y/n) ")) {

        for (const auto &queueURL: queueURLS) {
            // 9.  Delete an SQS queue.
            Aws::SQS::Model::DeleteQueueRequest request;
            request.SetQueueUrl(queueURL);

            Aws::SQS::Model::DeleteQueueOutcome outcome =
                    sqsClient.DeleteQueue(request);

            if (outcome.IsSuccess()) {
                std::cout << "The queue with URL '" << queueURL
                          << "' was successfully deleted." << std::endl;
            }
            else {
                std::cerr << "Error with SQS::DeleteQueue. "
                          << outcome.GetError().GetMessage()
                          << std::endl;
                result = false;
            }
        }

        for (const auto &subscriptionARN: subscriptionARNS) {
            // 10. Unsubscribe an SNS subscription.
            Aws::SNS::Model::UnsubscribeRequest request;
            request.SetSubscriptionArn(subscriptionARN);

            Aws::SNS::Model::UnsubscribeOutcome outcome =
                    snsClient.Unsubscribe(request);

            if (outcome.IsSuccess()) {
                std::cout << "Unsubscribe of subscription ARN '" << subscriptionARN
                          << "' was successful." << std::endl;
            }
            else {
                std::cerr << "Error with TopicsAndQueues::Unsubscribe. "
                          << outcome.GetError().GetMessage()
                          << std::endl;
                result = false;
            }
        }
    }

    printAsterisksLine();
    if (!topicARN.empty() && askUser &&
        askYesNoQuestion("Delete the SNS topic? (y/n) ")) {

        // 11. Delete an SNS topic.
        Aws::SNS::Model::DeleteTopicRequest request;
        request.SetTopicArn(topicARN);

        Aws::SNS::Model::DeleteTopicOutcome outcome = snsClient.DeleteTopic(request);

        if (outcome.IsSuccess()) {
            std::cout << "The topic with ARN '" << topicARN
                      << "' was successfully deleted." << std::endl;
        }
        else {
            std::cerr << "Error with TopicsAndQueues::DeleteTopicRequest. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            result = false;
        }
    }

    return result;
}

//! Create an IAM policy that gives an SQS queue permission to receive messages from an SNS topic.
/*!
 \sa createPolicyForQueue()
 \param queueARN: The SQS queue Amazon Resource Name (ARN).
 \param topicARN: The SNS topic ARN.
 \return Aws::String: The policy as JSON.
 */
Aws::String AwsDoc::TopicsAndQueues::createPolicyForQueue(const Aws::String &queueARN,
                                                          const Aws::String &topicARN) {
    std::ostringstream policyStream;
    policyStream << R"({
        "Statement": [
        {
            "Effect": "Allow",
                    "Principal": {
                "Service": "sns.amazonaws.com"
            },
            "Action": "sqs:SendMessage",
                    "Resource": ")" << queueARN << R"(",
                    "Condition": {
                "ArnEquals": {
                    "aws:SourceArn": ")" << topicARN << R"("
                }
            }
        }
        ]
    })";

    return policyStream.str();
}