Amazon IoT 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 iot)

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

# 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_iot.cpp)

target_link_libraries(${PROJECT_NAME}
        ${AWSSDK_LINK_LIBRARIES})

Code for the hello_iot.cpp source file.

#include <aws/core/Aws.h>
#include <aws/iot/IoTClient.h>
#include <aws/iot/model/ListThingsRequest.h>
#include <iostream>

/*
 *  A "Hello IoT" starter application which initializes an AWS IoT client and
 *  lists the AWS IoT topics in the current account.
 *
 *  main function
 *
 *  Usage: 'hello_iot'
 *
 */

int main(int argc, char **argv) {
    Aws::SDKOptions options;
    //  Optional: change the log level for debugging.
    //  options.loggingOptions.logLevel = Aws::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::IoT::IoTClient iotClient(clientConfig);
        // List the things in the current account.
        Aws::IoT::Model::ListThingsRequest listThingsRequest;

        Aws::String nextToken; // Used for pagination.
        Aws::Vector<Aws::IoT::Model::ThingAttribute> allThings;

        do {
            if (!nextToken.empty()) {
                listThingsRequest.SetNextToken(nextToken);
            }

            Aws::IoT::Model::ListThingsOutcome listThingsOutcome = iotClient.ListThings(
                    listThingsRequest);
            if (listThingsOutcome.IsSuccess()) {
                const Aws::Vector<Aws::IoT::Model::ThingAttribute> &things = listThingsOutcome.GetResult().GetThings();
                allThings.insert(allThings.end(), things.begin(), things.end());
                nextToken = listThingsOutcome.GetResult().GetNextToken();
            }
            else {
                std::cerr << "List things failed"
                          << listThingsOutcome.GetError().GetMessage() << std::endl;
                break;
            }
        } while (!nextToken.empty());

        std::cout << allThings.size() << " thing(s) found." << std::endl;
        for (auto const &thing: allThings) {
            std::cout << thing.GetThingName() << std::endl;
        }
    }

    Aws::ShutdownAPI(options); // Should only be called once.
    return 0;
}

//! Attach a principal to an AWS IoT thing.
/*!
  \param principal: A principal to attach.
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::attachThingPrincipal(const Aws::String &principal,
                                       const Aws::String &thingName,
                                       const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient client(clientConfiguration);
    Aws::IoT::Model::AttachThingPrincipalRequest request;
    request.SetPrincipal(principal);
    request.SetThingName(thingName);
    Aws::IoT::Model::AttachThingPrincipalOutcome outcome = client.AttachThingPrincipal(
            request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully attached principal to thing." << std::endl;
    }
    else {
        std::cerr << "Failed to attach principal to thing." <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Create keys and certificate for an Aws IoT device.
//! This routine will save certificates and keys to an output folder, if provided.
/*!
  \param outputFolder: Location for storing output in files, ignored when string is empty.
  \param certificateARNResult: A string to receive the ARN of the created certificate.
  \param certificateID: A string to receive the ID of the created certificate.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::createKeysAndCertificate(const Aws::String &outputFolder,
                                           Aws::String &certificateARNResult,
                                           Aws::String &certificateID,
                                           const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient client(clientConfiguration);
    Aws::IoT::Model::CreateKeysAndCertificateRequest createKeysAndCertificateRequest;

    Aws::IoT::Model::CreateKeysAndCertificateOutcome outcome =
            client.CreateKeysAndCertificate(createKeysAndCertificateRequest);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully created a certificate and keys" << std::endl;
        certificateARNResult = outcome.GetResult().GetCertificateArn();
        certificateID = outcome.GetResult().GetCertificateId();
        std::cout << "Certificate ARN: " << certificateARNResult << ", certificate ID: "
                  << certificateID << std::endl;

        if (!outputFolder.empty()) {
            std::cout << "Writing certificate and keys to the folder '" << outputFolder
                      << "'." << std::endl;
            std::cout << "Be sure these files are stored securely." << std::endl;

            Aws::String certificateFilePath = outputFolder + "/certificate.pem.crt";
            std::ofstream certificateFile(certificateFilePath);
            if (!certificateFile.is_open()) {
                std::cerr << "Error opening certificate file, '" << certificateFilePath
                          << "'."
                          << std::endl;
                return false;
            }
            certificateFile << outcome.GetResult().GetCertificatePem();
            certificateFile.close();

            const Aws::IoT::Model::KeyPair &keyPair = outcome.GetResult().GetKeyPair();

            Aws::String privateKeyFilePath = outputFolder + "/private.pem.key";
            std::ofstream privateKeyFile(privateKeyFilePath);
            if (!privateKeyFile.is_open()) {
                std::cerr << "Error opening private key file, '" << privateKeyFilePath
                          << "'."
                          << std::endl;
                return false;
            }
            privateKeyFile << keyPair.GetPrivateKey();
            privateKeyFile.close();

            Aws::String publicKeyFilePath = outputFolder + "/public.pem.key";
            std::ofstream publicKeyFile(publicKeyFilePath);
            if (!publicKeyFile.is_open()) {
                std::cerr << "Error opening public key file, '" << publicKeyFilePath
                          << "'."
                          << std::endl;
                return false;
            }
            publicKeyFile << keyPair.GetPublicKey();
        }
    }
    else {
        std::cerr << "Error creating keys and certificate: "
                  << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Create an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::createThing(const Aws::String &thingName,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::CreateThingRequest createThingRequest;
    createThingRequest.SetThingName(thingName);

    Aws::IoT::Model::CreateThingOutcome outcome = iotClient.CreateThing(
            createThingRequest);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully created thing " << thingName << std::endl;
    }
    else {
        std::cerr << "Failed to create thing " << thingName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Create an AWS IoT rule with an SNS topic as the target.
/*!
  \param ruleName: The name for the rule.
  \param snsTopic: The SNS topic ARN for the action.
  \param sql: The SQL statement used to query the topic.
  \param roleARN: The IAM role ARN for the action.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool
AwsDoc::IoT::createTopicRule(const Aws::String &ruleName,
                             const Aws::String &snsTopicARN, const Aws::String &sql,
                             const Aws::String &roleARN,
                             const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::CreateTopicRuleRequest request;
    request.SetRuleName(ruleName);

    Aws::IoT::Model::SnsAction snsAction;
    snsAction.SetTargetArn(snsTopicARN);
    snsAction.SetRoleArn(roleARN);

    Aws::IoT::Model::Action action;
    action.SetSns(snsAction);

    Aws::IoT::Model::TopicRulePayload topicRulePayload;
    topicRulePayload.SetSql(sql);
    topicRulePayload.SetActions({action});

    request.SetTopicRulePayload(topicRulePayload);
    auto outcome = iotClient.CreateTopicRule(request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully created topic rule " << ruleName << "." << std::endl;
    }
    else {
        std::cerr << "Error creating topic rule " << ruleName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }
    return outcome.IsSuccess();
}

//! Delete a certificate.
/*!
  \param certificateID: The ID of a certificate.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::deleteCertificate(const Aws::String &certificateID,
                                    const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::DeleteCertificateRequest request;
    request.SetCertificateId(certificateID);

    Aws::IoT::Model::DeleteCertificateOutcome outcome = iotClient.DeleteCertificate(
            request);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted certificate " << certificateID << std::endl;
    }
    else {
        std::cerr << "Error deleting certificate " << certificateID << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Delete an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::deleteThing(const Aws::String &thingName,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::DeleteThingRequest request;
    request.SetThingName(thingName);
    const auto outcome = iotClient.DeleteThing(request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted thing " << thingName << std::endl;
    }
    else {
        std::cerr << "Error deleting thing " << thingName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Delete an AWS IoT rule.
/*!
  \param ruleName: The name for the rule.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::deleteTopicRule(const Aws::String &ruleName,
                                  const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::DeleteTopicRuleRequest request;
    request.SetRuleName(ruleName);

    Aws::IoT::Model::DeleteTopicRuleOutcome outcome = iotClient.DeleteTopicRule(
            request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted rule " << ruleName << std::endl;
    }
    else {
        std::cerr << "Failed to delete rule " << ruleName <<
                  ": " << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Describe the endpoint specific to the AWS account making the call.
/*!
  \param endpointResult: String to receive the endpoint result.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::describeEndpoint(Aws::String &endpointResult,
                                   const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::String endpoint;
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::DescribeEndpointRequest describeEndpointRequest;
    describeEndpointRequest.SetEndpointType(
            "iot:Data-ATS"); // Recommended endpoint type.

    Aws::IoT::Model::DescribeEndpointOutcome outcome = iotClient.DescribeEndpoint(
            describeEndpointRequest);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully described endpoint." << std::endl;
        endpointResult = outcome.GetResult().GetEndpointAddress();
    }
    else {
        std::cerr << "Error describing endpoint" << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

//! Describe an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::describeThing(const Aws::String &thingName,
                                const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::DescribeThingRequest request;
    request.SetThingName(thingName);

    Aws::IoT::Model::DescribeThingOutcome outcome = iotClient.DescribeThing(request);

    if (outcome.IsSuccess()) {
        const Aws::IoT::Model::DescribeThingResult &result = outcome.GetResult();
        std::cout << "Retrieved thing '" << result.GetThingName() << "'" << std::endl;
        std::cout << "thingArn: " << result.GetThingArn() << std::endl;
        std::cout << result.GetAttributes().size() << " attribute(s) retrieved"
                  << std::endl;
        for (const auto &attribute: result.GetAttributes()) {
            std::cout << "  attribute: " << attribute.first << "=" << attribute.second
                      << std::endl;
        }
    }
    else {
        std::cerr << "Error describing thing " << thingName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Detach a principal from an AWS IoT thing.
/*!
  \param principal: A principal to detach.
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::detachThingPrincipal(const Aws::String &principal,
                                       const Aws::String &thingName,
                                       const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::DetachThingPrincipalRequest detachThingPrincipalRequest;
    detachThingPrincipalRequest.SetThingName(thingName);
    detachThingPrincipalRequest.SetPrincipal(principal);

    Aws::IoT::Model::DetachThingPrincipalOutcome outcome = iotClient.DetachThingPrincipal(
            detachThingPrincipalRequest);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully detached principal " << principal << " from thing "
                  << thingName << std::endl;
    }
    else {
        std::cerr << "Failed to detach principal " << principal << " from thing "
                  << thingName << ": "
                  << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! List certificates registered in the AWS account making the call.
/*!
   \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::listCertificates(
        const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::ListCertificatesRequest request;

    Aws::Vector<Aws::IoT::Model::Certificate> allCertificates;
    Aws::String marker; // Used to paginate results.
    do {
        if (!marker.empty()) {
            request.SetMarker(marker);
        }

        Aws::IoT::Model::ListCertificatesOutcome outcome = iotClient.ListCertificates(
                request);

        if (outcome.IsSuccess()) {
            const Aws::IoT::Model::ListCertificatesResult &result = outcome.GetResult();
            marker = result.GetNextMarker();
            allCertificates.insert(allCertificates.end(),
                                   result.GetCertificates().begin(),
                                   result.GetCertificates().end());
        }
        else {
            std::cerr << "Error: " << outcome.GetError().GetMessage() << std::endl;
            return false;
        }
    } while (!marker.empty());

    std::cout << allCertificates.size() << " certificate(s) found." << std::endl;

    for (auto &certificate: allCertificates) {
        std::cout << "Certificate ID: " << certificate.GetCertificateId() << std::endl;
        std::cout << "Certificate ARN: " << certificate.GetCertificateArn()
                  << std::endl;
        std::cout << std::endl;
    }

    return true;
}

//! Query the AWS IoT fleet index.
//! For query information, see https://docs.aws.amazon.com/iot/latest/developerguide/query-syntax.html
/*!
  \param: query: The query string.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::searchIndex(const Aws::String &query,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::SearchIndexRequest request;
    request.SetQueryString(query);

    Aws::Vector<Aws::IoT::Model::ThingDocument> allThingDocuments;
    Aws::String nextToken; // Used for pagination.
    do {
        if (!nextToken.empty()) {
            request.SetNextToken(nextToken);
        }

        Aws::IoT::Model::SearchIndexOutcome outcome = iotClient.SearchIndex(request);

        if (outcome.IsSuccess()) {
            const Aws::IoT::Model::SearchIndexResult &result = outcome.GetResult();
            allThingDocuments.insert(allThingDocuments.end(),
                                     result.GetThings().cbegin(),
                                     result.GetThings().cend());
            nextToken = result.GetNextToken();

        }
        else {
            std::cerr << "Error in SearchIndex: " << outcome.GetError().GetMessage()
                      << std::endl;
            return false;
        }
    } while (!nextToken.empty());

    std::cout << allThingDocuments.size() << " thing document(s) found." << std::endl;
    for (const auto thingDocument: allThingDocuments) {
        std::cout << "  Thing name: " << thingDocument.GetThingName() << "."
                  << std::endl;
    }
    return true;
}

//! Update the indexing configuration.
/*!
  \param thingIndexingConfiguration: A ThingIndexingConfiguration object which is ignored if not set.
  \param thingGroupIndexingConfiguration: A ThingGroupIndexingConfiguration object which is ignored if not set.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::updateIndexingConfiguration(
        const Aws::IoT::Model::ThingIndexingConfiguration &thingIndexingConfiguration,
        const Aws::IoT::Model::ThingGroupIndexingConfiguration &thingGroupIndexingConfiguration,
        const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::UpdateIndexingConfigurationRequest request;

    if (thingIndexingConfiguration.ThingIndexingModeHasBeenSet()) {
        request.SetThingIndexingConfiguration(thingIndexingConfiguration);
    }

    if (thingGroupIndexingConfiguration.ThingGroupIndexingModeHasBeenSet()) {
        request.SetThingGroupIndexingConfiguration(thingGroupIndexingConfiguration);
    }

    Aws::IoT::Model::UpdateIndexingConfigurationOutcome outcome = iotClient.UpdateIndexingConfiguration(
            request);

    if (outcome.IsSuccess()) {
        std::cout << "UpdateIndexingConfiguration succeeded." << std::endl;
    }
    else {
        std::cerr << "UpdateIndexingConfiguration failed."
                  << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Update an AWS IoT thing with attributes.
/*!
  \param thingName: The name for the thing.
  \param attributeMap: A map of key/value attributes/
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::updateThing(const Aws::String &thingName,
                              const std::map<Aws::String, Aws::String> &attributeMap,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::UpdateThingRequest request;
    request.SetThingName(thingName);
    Aws::IoT::Model::AttributePayload attributePayload;
    for (const auto &attribute: attributeMap) {
        attributePayload.AddAttributes(attribute.first, attribute.second);
    }
    request.SetAttributePayload(attributePayload);

    Aws::IoT::Model::UpdateThingOutcome outcome = iotClient.UpdateThing(request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully updated thing " << thingName << std::endl;
    }
    else {
        std::cerr << "Failed to update thing " << thingName << ":" <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

Create an Amazon IoT thing.

    Aws::String thingName = askQuestion("Enter a thing name: ");

    if (!createThing(thingName, clientConfiguration)) {
        std::cerr << "Exiting because createThing failed." << std::endl;
        cleanup("", "", "", "", "", false, clientConfiguration);
        return false;
    }

//! Create an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::createThing(const Aws::String &thingName,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::CreateThingRequest createThingRequest;
    createThingRequest.SetThingName(thingName);

    Aws::IoT::Model::CreateThingOutcome outcome = iotClient.CreateThing(
            createThingRequest);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully created thing " << thingName << std::endl;
    }
    else {
        std::cerr << "Failed to create thing " << thingName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

Generate and attach a device certificate.

    Aws::String certificateARN;
    Aws::String certificateID;
    if (askYesNoQuestion("Would you like to create a certificate for your thing? (y/n) ")) {
        Aws::String outputFolder;
        if (askYesNoQuestion(
                "Would you like to save the certificate and keys to file? (y/n) ")) {
            outputFolder = std::filesystem::current_path();
            outputFolder += "/device_keys_and_certificates";

            std::filesystem::create_directories(outputFolder);

            std::cout << "The certificate and keys will be saved to the folder: "
                      << outputFolder << std::endl;
        }

        if (!createKeysAndCertificate(outputFolder, certificateARN, certificateID,
                                      clientConfiguration)) {
            std::cerr << "Exiting because createKeysAndCertificate failed."
                      << std::endl;
            cleanup(thingName, "", "", "", "", false, clientConfiguration);
            return false;
        }

        std::cout << "\nNext, the certificate will be attached to the thing.\n"
                  << std::endl;
        if (!attachThingPrincipal(certificateARN, thingName, clientConfiguration)) {
            std::cerr << "Exiting because attachThingPrincipal failed." << std::endl;
            cleanup(thingName, certificateARN, certificateID, "", "",
                    false,
                    clientConfiguration);
            return false;
        }
    }

//! Create keys and certificate for an Aws IoT device.
//! This routine will save certificates and keys to an output folder, if provided.
/*!
  \param outputFolder: Location for storing output in files, ignored when string is empty.
  \param certificateARNResult: A string to receive the ARN of the created certificate.
  \param certificateID: A string to receive the ID of the created certificate.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::createKeysAndCertificate(const Aws::String &outputFolder,
                                           Aws::String &certificateARNResult,
                                           Aws::String &certificateID,
                                           const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient client(clientConfiguration);
    Aws::IoT::Model::CreateKeysAndCertificateRequest createKeysAndCertificateRequest;

    Aws::IoT::Model::CreateKeysAndCertificateOutcome outcome =
            client.CreateKeysAndCertificate(createKeysAndCertificateRequest);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully created a certificate and keys" << std::endl;
        certificateARNResult = outcome.GetResult().GetCertificateArn();
        certificateID = outcome.GetResult().GetCertificateId();
        std::cout << "Certificate ARN: " << certificateARNResult << ", certificate ID: "
                  << certificateID << std::endl;

        if (!outputFolder.empty()) {
            std::cout << "Writing certificate and keys to the folder '" << outputFolder
                      << "'." << std::endl;
            std::cout << "Be sure these files are stored securely." << std::endl;

            Aws::String certificateFilePath = outputFolder + "/certificate.pem.crt";
            std::ofstream certificateFile(certificateFilePath);
            if (!certificateFile.is_open()) {
                std::cerr << "Error opening certificate file, '" << certificateFilePath
                          << "'."
                          << std::endl;
                return false;
            }
            certificateFile << outcome.GetResult().GetCertificatePem();
            certificateFile.close();

            const Aws::IoT::Model::KeyPair &keyPair = outcome.GetResult().GetKeyPair();

            Aws::String privateKeyFilePath = outputFolder + "/private.pem.key";
            std::ofstream privateKeyFile(privateKeyFilePath);
            if (!privateKeyFile.is_open()) {
                std::cerr << "Error opening private key file, '" << privateKeyFilePath
                          << "'."
                          << std::endl;
                return false;
            }
            privateKeyFile << keyPair.GetPrivateKey();
            privateKeyFile.close();

            Aws::String publicKeyFilePath = outputFolder + "/public.pem.key";
            std::ofstream publicKeyFile(publicKeyFilePath);
            if (!publicKeyFile.is_open()) {
                std::cerr << "Error opening public key file, '" << publicKeyFilePath
                          << "'."
                          << std::endl;
                return false;
            }
            publicKeyFile << keyPair.GetPublicKey();
        }
    }
    else {
        std::cerr << "Error creating keys and certificate: "
                  << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Attach a principal to an AWS IoT thing.
/*!
  \param principal: A principal to attach.
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::attachThingPrincipal(const Aws::String &principal,
                                       const Aws::String &thingName,
                                       const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient client(clientConfiguration);
    Aws::IoT::Model::AttachThingPrincipalRequest request;
    request.SetPrincipal(principal);
    request.SetThingName(thingName);
    Aws::IoT::Model::AttachThingPrincipalOutcome outcome = client.AttachThingPrincipal(
            request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully attached principal to thing." << std::endl;
    }
    else {
        std::cerr << "Failed to attach principal to thing." <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

Perform various operations on the Amazon IoT thing.

    if (!updateThing(thingName, { {"location", "Office"}, {"firmwareVersion", "v2.0"} }, clientConfiguration)) {
        std::cerr << "Exiting because updateThing failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, "", "", false,
                clientConfiguration);
        return false;
    }

    printAsterisksLine();

    std::cout << "Now an endpoint will be retrieved for your account.\n" << std::endl;
    std::cout << "An IoT Endpoint refers to a specific URL or Uniform Resource Locator that serves as the entry point\n"
    << "for communication between IoT devices and the AWS IoT service." << std::endl;

    askQuestion("Press Enter to continue:", alwaysTrueTest);

    Aws::String endpoint;
    if (!describeEndpoint(endpoint, clientConfiguration)) {
        std::cerr << "Exiting because getEndpoint failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, "", "", false,
                clientConfiguration);
        return false;
    }
    std::cout <<"Your endpoint is " << endpoint << "." << std::endl;
    printAsterisksLine();

    std::cout << "Now the certificates in your account will be listed." << std::endl;
    askQuestion("Press Enter to continue:", alwaysTrueTest);

    if (!listCertificates(clientConfiguration)) {
        std::cerr << "Exiting because listCertificates failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, "", "", false,
                clientConfiguration);
        return false;
    }

    printAsterisksLine();

    std::cout << "Now the shadow for the thing will be updated.\n" << std::endl;
    std::cout << "A thing shadow refers to a feature that enables you to create a virtual representation, or \"shadow,\"\n"
    << "of a physical device or thing. The thing shadow allows you to synchronize and control the state of a device between\n"
    << "the cloud and the device itself. and the AWS IoT service. For example, you can write and retrieve JSON data from a thing shadow." << std::endl;
    askQuestion("Press Enter to continue:", alwaysTrueTest);

    if (!updateThingShadow(thingName, R"({"state":{"reported":{"temperature":25,"humidity":50}}})", clientConfiguration)) {
        std::cerr << "Exiting because updateThingShadow failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, "", "", false,
                clientConfiguration);
        return false;
    }

    printAsterisksLine();

    std::cout << "Now, the state information for the shadow will be retrieved.\n" << std::endl;
    askQuestion("Press Enter to continue:", alwaysTrueTest);

    Aws::String shadowState;
    if (!getThingShadow(thingName, shadowState, clientConfiguration)) {
        std::cerr << "Exiting because getThingShadow failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, "", "", false,
                clientConfiguration);
        return false;
    }
    std::cout << "The retrieved shadow state is: " << shadowState << std::endl;

    printAsterisksLine();

    std::cout << "A rule with now be added to to the thing.\n" << std::endl;
    std::cout << "Any user who has permission to create rules will be able to access data processed by the rule." << std::endl;
    std::cout << "In this case, the rule will use an Simple Notification Service (SNS) topic and an IAM rule." << std::endl;
    std::cout << "These resources will be created using a CloudFormation template." << std::endl;
    std::cout << "Stack creation may take a few minutes." << std::endl;

    askQuestion("Press Enter to continue: ", alwaysTrueTest);
    Aws::Map<Aws::String, Aws::String> outputs =createCloudFormationStack(STACK_NAME,clientConfiguration);
    if (outputs.empty()) {
        std::cerr << "Exiting because createCloudFormationStack failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, "", "", false,
                clientConfiguration);
        return false;
    }

    // Retrieve the topic ARN and role ARN from the CloudFormation stack outputs.
    auto topicArnIter = outputs.find(SNS_TOPIC_ARN_OUTPUT);
    auto roleArnIter = outputs.find(ROLE_ARN_OUTPUT);
    if ((topicArnIter == outputs.end()) || (roleArnIter == outputs.end())) {
        std::cerr << "Exiting because output '" << SNS_TOPIC_ARN_OUTPUT <<
        "' or '" << ROLE_ARN_OUTPUT << "'not found in the CloudFormation stack."  << std::endl;
        cleanup(thingName, certificateARN, certificateID, STACK_NAME, "",
                false,
                clientConfiguration);
        return false;
    }

    Aws::String topicArn = topicArnIter->second;
    Aws::String roleArn = roleArnIter->second;
    Aws::String sqlStatement = "SELECT * FROM '";
    sqlStatement += MQTT_MESSAGE_TOPIC_FILTER;
    sqlStatement += "'";

    printAsterisksLine();

    std::cout << "Now a rule will be created.\n" << std::endl;
    std::cout << "Rules are an administrator-level action. Any user who has permission\n"
                 << "to create rules will be able to access data processed by the rule." << std::endl;
    std::cout << "In this case, the rule will use an SNS topic" << std::endl;
    std::cout << "and the following SQL statement '" << sqlStatement << "'." << std::endl;
    std::cout << "For more information on IoT SQL, see https://docs.aws.amazon.com/iot/latest/developerguide/iot-sql-reference.html" << std::endl;
    Aws::String ruleName = askQuestion("Enter a rule name: ");
    if (!createTopicRule(ruleName, topicArn, sqlStatement, roleArn, clientConfiguration)) {
        std::cerr << "Exiting because createRule failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, STACK_NAME, "",
                false,
                clientConfiguration);
        return false;
    }

    printAsterisksLine();

    std::cout << "Now your rules will be listed.\n" << std::endl;
    askQuestion("Press Enter to continue: ", alwaysTrueTest);
    if (!listTopicRules(clientConfiguration)) {
        std::cerr << "Exiting because listRules failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, STACK_NAME, ruleName,
                false,
                clientConfiguration);
        return false;
    }

    printAsterisksLine();
    Aws::String queryString = "thingName:" + thingName;
    std::cout << "Now the AWS IoT fleet index will be queried with the query\n'"
    << queryString << "'.\n" << std::endl;
    std::cout << "For query information, see https://docs.aws.amazon.com/iot/latest/developerguide/query-syntax.html" << std::endl;

    std::cout << "For this query to work, thing indexing must be enabled in your account.\n"
    << "This can be done with the awscli command line by calling 'aws iot update-indexing-configuration'\n"
       << "or it can be done programmatically." << std::endl;
    std::cout << "For more information, see https://docs.aws.amazon.com/iot/latest/developerguide/managing-index.html" << std::endl;
    if (askYesNoQuestion("Do you want to enable thing indexing in your account? (y/n) "))
    {
        Aws::IoT::Model::ThingIndexingConfiguration thingIndexingConfiguration;
        thingIndexingConfiguration.SetThingIndexingMode(Aws::IoT::Model::ThingIndexingMode::REGISTRY_AND_SHADOW);
        thingIndexingConfiguration.SetThingConnectivityIndexingMode(Aws::IoT::Model::ThingConnectivityIndexingMode::STATUS);
        // The ThingGroupIndexingConfiguration object is ignored if not set.
        Aws::IoT::Model::ThingGroupIndexingConfiguration thingGroupIndexingConfiguration;
        if (!updateIndexingConfiguration(thingIndexingConfiguration, thingGroupIndexingConfiguration, clientConfiguration)) {
            std::cerr << "Exiting because updateIndexingConfiguration failed." << std::endl;
            cleanup(thingName, certificateARN, certificateID, STACK_NAME,
                    ruleName, false,
                    clientConfiguration);
            return false;
        }
    }

    if (!searchIndex(queryString, clientConfiguration)) {

        std::cerr << "Exiting because searchIndex failed." << std::endl;
        cleanup(thingName, certificateARN, certificateID, STACK_NAME, ruleName,
                false,
                clientConfiguration);
        return false;
    }

//! Update an AWS IoT thing with attributes.
/*!
  \param thingName: The name for the thing.
  \param attributeMap: A map of key/value attributes/
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::updateThing(const Aws::String &thingName,
                              const std::map<Aws::String, Aws::String> &attributeMap,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::UpdateThingRequest request;
    request.SetThingName(thingName);
    Aws::IoT::Model::AttributePayload attributePayload;
    for (const auto &attribute: attributeMap) {
        attributePayload.AddAttributes(attribute.first, attribute.second);
    }
    request.SetAttributePayload(attributePayload);

    Aws::IoT::Model::UpdateThingOutcome outcome = iotClient.UpdateThing(request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully updated thing " << thingName << std::endl;
    }
    else {
        std::cerr << "Failed to update thing " << thingName << ":" <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Describe the endpoint specific to the AWS account making the call.
/*!
  \param endpointResult: String to receive the endpoint result.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::describeEndpoint(Aws::String &endpointResult,
                                   const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::String endpoint;
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::DescribeEndpointRequest describeEndpointRequest;
    describeEndpointRequest.SetEndpointType(
            "iot:Data-ATS"); // Recommended endpoint type.

    Aws::IoT::Model::DescribeEndpointOutcome outcome = iotClient.DescribeEndpoint(
            describeEndpointRequest);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully described endpoint." << std::endl;
        endpointResult = outcome.GetResult().GetEndpointAddress();
    }
    else {
        std::cerr << "Error describing endpoint" << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

//! List certificates registered in the AWS account making the call.
/*!
   \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::listCertificates(
        const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::ListCertificatesRequest request;

    Aws::Vector<Aws::IoT::Model::Certificate> allCertificates;
    Aws::String marker; // Used to paginate results.
    do {
        if (!marker.empty()) {
            request.SetMarker(marker);
        }

        Aws::IoT::Model::ListCertificatesOutcome outcome = iotClient.ListCertificates(
                request);

        if (outcome.IsSuccess()) {
            const Aws::IoT::Model::ListCertificatesResult &result = outcome.GetResult();
            marker = result.GetNextMarker();
            allCertificates.insert(allCertificates.end(),
                                   result.GetCertificates().begin(),
                                   result.GetCertificates().end());
        }
        else {
            std::cerr << "Error: " << outcome.GetError().GetMessage() << std::endl;
            return false;
        }
    } while (!marker.empty());

    std::cout << allCertificates.size() << " certificate(s) found." << std::endl;

    for (auto &certificate: allCertificates) {
        std::cout << "Certificate ID: " << certificate.GetCertificateId() << std::endl;
        std::cout << "Certificate ARN: " << certificate.GetCertificateArn()
                  << std::endl;
        std::cout << std::endl;
    }

    return true;
}

//! Update the shadow of an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param document: The state information, in JSON format.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::updateThingShadow(const Aws::String &thingName,
                                    const Aws::String &document,
                                    const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoTDataPlane::IoTDataPlaneClient iotDataPlaneClient(clientConfiguration);
    Aws::IoTDataPlane::Model::UpdateThingShadowRequest updateThingShadowRequest;
    updateThingShadowRequest.SetThingName(thingName);
    std::shared_ptr<std::stringstream> streamBuf = std::make_shared<std::stringstream>(
            document);
    updateThingShadowRequest.SetBody(streamBuf);
    Aws::IoTDataPlane::Model::UpdateThingShadowOutcome outcome = iotDataPlaneClient.UpdateThingShadow(
            updateThingShadowRequest);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully updated thing shadow." << std::endl;
    }
    else {
        std::cerr << "Error while updating thing shadow."
                  << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Get the shadow of an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param documentResult: String to receive the state information, in JSON format.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::getThingShadow(const Aws::String &thingName,
                                 Aws::String &documentResult,
                                 const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoTDataPlane::IoTDataPlaneClient iotClient(clientConfiguration);
    Aws::IoTDataPlane::Model::GetThingShadowRequest request;
    request.SetThingName(thingName);
    auto outcome = iotClient.GetThingShadow(request);
    if (outcome.IsSuccess()) {
        std::stringstream ss;
        ss << outcome.GetResult().GetPayload().rdbuf();
        documentResult = ss.str();
    }
    else {
        std::cerr << "Error getting thing shadow: " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Create an AWS IoT rule with an SNS topic as the target.
/*!
  \param ruleName: The name for the rule.
  \param snsTopic: The SNS topic ARN for the action.
  \param sql: The SQL statement used to query the topic.
  \param roleARN: The IAM role ARN for the action.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool
AwsDoc::IoT::createTopicRule(const Aws::String &ruleName,
                             const Aws::String &snsTopicARN, const Aws::String &sql,
                             const Aws::String &roleARN,
                             const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::CreateTopicRuleRequest request;
    request.SetRuleName(ruleName);

    Aws::IoT::Model::SnsAction snsAction;
    snsAction.SetTargetArn(snsTopicARN);
    snsAction.SetRoleArn(roleARN);

    Aws::IoT::Model::Action action;
    action.SetSns(snsAction);

    Aws::IoT::Model::TopicRulePayload topicRulePayload;
    topicRulePayload.SetSql(sql);
    topicRulePayload.SetActions({action});

    request.SetTopicRulePayload(topicRulePayload);
    auto outcome = iotClient.CreateTopicRule(request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully created topic rule " << ruleName << "." << std::endl;
    }
    else {
        std::cerr << "Error creating topic rule " << ruleName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }
    return outcome.IsSuccess();
}

//! Lists the AWS IoT topic rules.
/*!
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::listTopicRules(
        const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::ListTopicRulesRequest request;

    Aws::Vector<Aws::IoT::Model::TopicRuleListItem> allRules;
    Aws::String nextToken; // Used for pagination.
    do {
        if (!nextToken.empty()) {
            request.SetNextToken(nextToken);
        }

        Aws::IoT::Model::ListTopicRulesOutcome outcome = iotClient.ListTopicRules(
                request);

        if (outcome.IsSuccess()) {
            const Aws::IoT::Model::ListTopicRulesResult &result = outcome.GetResult();
            allRules.insert(allRules.end(),
                            result.GetRules().cbegin(),
                            result.GetRules().cend());

            nextToken = result.GetNextToken();
        }
        else {
            std::cerr << "ListTopicRules error: " <<
                      outcome.GetError().GetMessage() << std::endl;
            return false;
        }

    } while (!nextToken.empty());

    std::cout << "ListTopicRules: " << allRules.size() << " rule(s) found."
              << std::endl;
    for (auto &rule: allRules) {
        std::cout << "  Rule name: " << rule.GetRuleName() << ", rule ARN: "
                  << rule.GetRuleArn() << "." << std::endl;
    }

    return true;
}

//! Query the AWS IoT fleet index.
//! For query information, see https://docs.aws.amazon.com/iot/latest/developerguide/query-syntax.html
/*!
  \param: query: The query string.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::searchIndex(const Aws::String &query,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::SearchIndexRequest request;
    request.SetQueryString(query);

    Aws::Vector<Aws::IoT::Model::ThingDocument> allThingDocuments;
    Aws::String nextToken; // Used for pagination.
    do {
        if (!nextToken.empty()) {
            request.SetNextToken(nextToken);
        }

        Aws::IoT::Model::SearchIndexOutcome outcome = iotClient.SearchIndex(request);

        if (outcome.IsSuccess()) {
            const Aws::IoT::Model::SearchIndexResult &result = outcome.GetResult();
            allThingDocuments.insert(allThingDocuments.end(),
                                     result.GetThings().cbegin(),
                                     result.GetThings().cend());
            nextToken = result.GetNextToken();

        }
        else {
            std::cerr << "Error in SearchIndex: " << outcome.GetError().GetMessage()
                      << std::endl;
            return false;
        }
    } while (!nextToken.empty());

    std::cout << allThingDocuments.size() << " thing document(s) found." << std::endl;
    for (const auto thingDocument: allThingDocuments) {
        std::cout << "  Thing name: " << thingDocument.GetThingName() << "."
                  << std::endl;
    }
    return true;
}

Clean up resources.

bool
AwsDoc::IoT::cleanup(const Aws::String &thingName, const Aws::String &certificateARN,
                     const Aws::String &certificateID, const Aws::String &stackName,
                     const Aws::String &ruleName, bool askForConfirmation,
                     const Aws::Client::ClientConfiguration &clientConfiguration) {
    bool result = true;

    if (!ruleName.empty() && (!askForConfirmation ||
                               askYesNoQuestion("Delete the rule '" + ruleName +
                                                "'? (y/n) "))) {
        result &= deleteTopicRule(ruleName, clientConfiguration);
    }

    Aws::CloudFormation::CloudFormationClient cloudFormationClient(clientConfiguration);

    if (!stackName.empty() && (!askForConfirmation ||
                               askYesNoQuestion(
                                       "Delete the CloudFormation stack '" + stackName +
                                       "'? (y/n) "))) {
        result &= deleteStack(stackName, clientConfiguration);
    }

    if (!certificateARN.empty() && (!askForConfirmation ||
                                    askYesNoQuestion("Delete the certificate '" +
                                                     certificateARN + "'? (y/n) "))) {
        result &= detachThingPrincipal(certificateARN, thingName, clientConfiguration);
        result &= deleteCertificate(certificateID, clientConfiguration);
    }

    if (!thingName.empty() && (!askForConfirmation ||
                               askYesNoQuestion("Delete the thing '" + thingName +
                                                "'? (y/n) "))) {
        result &= deleteThing(thingName, clientConfiguration);
    }

    return result;
}

//! Detach a principal from an AWS IoT thing.
/*!
  \param principal: A principal to detach.
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::detachThingPrincipal(const Aws::String &principal,
                                       const Aws::String &thingName,
                                       const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::DetachThingPrincipalRequest detachThingPrincipalRequest;
    detachThingPrincipalRequest.SetThingName(thingName);
    detachThingPrincipalRequest.SetPrincipal(principal);

    Aws::IoT::Model::DetachThingPrincipalOutcome outcome = iotClient.DetachThingPrincipal(
            detachThingPrincipalRequest);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully detached principal " << principal << " from thing "
                  << thingName << std::endl;
    }
    else {
        std::cerr << "Failed to detach principal " << principal << " from thing "
                  << thingName << ": "
                  << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Delete a certificate.
/*!
  \param certificateID: The ID of a certificate.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::deleteCertificate(const Aws::String &certificateID,
                                    const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);

    Aws::IoT::Model::DeleteCertificateRequest request;
    request.SetCertificateId(certificateID);

    Aws::IoT::Model::DeleteCertificateOutcome outcome = iotClient.DeleteCertificate(
            request);

    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted certificate " << certificateID << std::endl;
    }
    else {
        std::cerr << "Error deleting certificate " << certificateID << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Delete an AWS IoT rule.
/*!
  \param ruleName: The name for the rule.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::deleteTopicRule(const Aws::String &ruleName,
                                  const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::DeleteTopicRuleRequest request;
    request.SetRuleName(ruleName);

    Aws::IoT::Model::DeleteTopicRuleOutcome outcome = iotClient.DeleteTopicRule(
            request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted rule " << ruleName << std::endl;
    }
    else {
        std::cerr << "Failed to delete rule " << ruleName <<
                  ": " << outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}

//! Delete an AWS IoT thing.
/*!
  \param thingName: The name for the thing.
  \param clientConfiguration: AWS client configuration.
  \return bool: Function succeeded.
 */
bool AwsDoc::IoT::deleteThing(const Aws::String &thingName,
                              const Aws::Client::ClientConfiguration &clientConfiguration) {
    Aws::IoT::IoTClient iotClient(clientConfiguration);
    Aws::IoT::Model::DeleteThingRequest request;
    request.SetThingName(thingName);
    const auto outcome = iotClient.DeleteThing(request);
    if (outcome.IsSuccess()) {
        std::cout << "Successfully deleted thing " << thingName << std::endl;
    }
    else {
        std::cerr << "Error deleting thing " << thingName << ": " <<
                  outcome.GetError().GetMessage() << std::endl;
    }

    return outcome.IsSuccess();
}