CachingDownloadManager.h

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/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

#ifndef ALEXA_CLIENT_SDK_LIBIPCSERVERSAMPLEAPP_INCLUDE_IPCSERVERSAMPLEAPP_CACHINGDOWNLOADMANAGER_H_
#define ALEXA_CLIENT_SDK_LIBIPCSERVERSAMPLEAPP_INCLUDE_IPCSERVERSAMPLEAPP_CACHINGDOWNLOADMANAGER_H_

#include <cstdint>
#include <memory>

#include <AVSCommon/Utils/LibcurlUtils/HTTPContentFetcherFactory.h>
#include <AVSCommon/Utils/Threading/Executor.h>
#include <AVSCommon/SDKInterfaces/Storage/MiscStorageInterface.h>

#include <RegistrationManager/CustomerDataHandler.h>

namespace alexaClientSDK {
namespace sampleApplications {
namespace ipcServerSampleApp {

class CachingDownloadManager : public registrationManager::CustomerDataHandler {
public:
    class Observer {
    public:
        Observer() = default;
        virtual ~Observer() = default;

        virtual void onDownloadStarted(){};

        virtual void onDownloadComplete(){};

        virtual void onDownloadFailed(){};

        virtual void onCacheHit(){};

        virtual void onBytesRead(uint64_t numberOfBytes){};
    };

    CachingDownloadManager(
        std::shared_ptr<avsCommon::sdkInterfaces::HTTPContentFetcherInterfaceFactoryInterface>
            httpContentFetcherInterfaceFactoryInterface,
        unsigned long cachePeriodInSeconds,
        unsigned long maxCacheSize,
        std::shared_ptr<avsCommon::sdkInterfaces::storage::MiscStorageInterface> miscStorage,
        const std::shared_ptr<registrationManager::CustomerDataManagerInterface> customerDataManager);

    std::string retrieveContent(const std::string& source, std::shared_ptr<Observer> observer = nullptr);

    class CachedContent {
    public:
        std::chrono::system_clock::time_point importTime;
        std::string content;

        CachedContent() = default;

        CachedContent(std::chrono::system_clock::time_point importTime, const std::string& content);
    };

private:
    std::string downloadFromSource(const std::string& source, std::shared_ptr<Observer> observer);
    void cleanUpCache();
    void writeToStorage(std::string source, CachedContent content);

    void clearData() override;

    void removeFromStorage(std::string source);
    std::shared_ptr<avsCommon::sdkInterfaces::HTTPContentFetcherInterfaceFactoryInterface> m_contentFetcherFactory;
    std::chrono::duration<double> m_cachePeriod;
    unsigned long m_maxCacheSize;
    std::unordered_map<std::string, CachingDownloadManager::CachedContent> cachedContentMap;
    std::mutex cachedContentMapMutex;
    std::shared_ptr<avsCommon::sdkInterfaces::storage::MiscStorageInterface> m_miscStorage;
    avsCommon::utils::threading::Executor m_executor;
};

inline std::string cachedContentToString(CachingDownloadManager::CachedContent content, std::string delimiter) {
    auto time = std::chrono::duration_cast<std::chrono::seconds>(content.importTime.time_since_epoch()).count();
    return std::to_string(time) + delimiter + content.content;
}

}  // namespace ipcServerSampleApp
}  // namespace sampleApplications
}  // namespace alexaClientSDK

#endif  // ALEXA_CLIENT_SDK_LIBIPCSERVERSAMPLEAPP_INCLUDE_IPCSERVERSAMPLEAPP_CACHINGDOWNLOADMANAGER_H_