Runtime C++ Download Portable [2027]
class DownloadManager public: using ProgressCallback = std::function<void(float progress, size_t downloaded, size_t total)>; using CompleteCallback = std::function<void(bool success, const std::string& error)>; struct DownloadOptions std::string url; std::string output_path; int timeout_seconds = 30; int max_retries = 3; bool resume_on_failure = true; std::string username; // Optional for auth std::string password; // Optional for auth std::string user_agent = "C++DownloadManager/1.0"; ; DownloadManager(); ~DownloadManager(); // Start async download void downloadAsync(const DownloadOptions& options, ProgressCallback progress = nullptr, CompleteCallback complete = nullptr); // Sync download with progress bool downloadSync(const DownloadOptions& options, ProgressCallback progress = nullptr); // Cancel active download void cancel(); // Check if download is active bool isActive() const return m_active; // Get last error std::string getLastError() const return m_lastError;
add_executable(downloader download_manager.cpp)
void DownloadManager::downloadAsync(const DownloadOptions& options, ProgressCallback progress, CompleteCallback complete) if (m_active) if (complete) complete(false, "Download already in progress"); return; m_active = true; m_downloadThread = std::thread([this, options, progress, complete]() bool result = downloadSync(options, progress); m_active = false; if (complete) complete(result, m_lastError); ); runtime c++ download
(for building):
private: static size_t writeCallback(void* contents, size_t size, size_t nmemb, void* userp); static int progressCallback(void* userp, curl_off_t dltotal, curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow); struct DownloadContext std::ofstream file; size_t downloaded_bytes = 0; size_t total_bytes = 0; ProgressCallback progress_cb; std::string output_path; bool resume_mode = false; ; std::unique_ptr<DownloadContext> m_context; std::thread m_downloadThread; std::atomic<bool> m_activefalse; std::atomic<bool> m_cancelfalse; std::string m_lastError; CURL* m_curl; ; using CompleteCallback = std::function<
int main() DownloadManager dm; DownloadManager::DownloadOptions options; options.url = "https://example.com/file.zip"; options.output_path = "downloaded_file.zip"; options.max_retries = 2; options.resume_on_failure = true; std::cout << "Starting download..." << std::endl; auto start_time = std::chrono::steady_clock::now(); // Async download with callbacks dm.downloadAsync(options, // Progress callback [](float progress, size_t downloaded, size_t total) std::cout << "\rProgress: " << (progress * 100) << "% (" << downloaded << "/" << total << " bytes)" << std::flush; , // Complete callback [&start_time](bool success, const std::string& error) auto end_time = std::chrono::steady_clock::now(); auto duration = std::chrono::duration_cast<std::chrono::seconds>(end_time - start_time); if (success) std::cout << "\nDownload completed in " << duration.count() << " seconds!" << std::endl; else std::cout << "\nDownload failed: " << error << std::endl; ); // Wait for completion while (dm.isActive()) std::this_thread::sleep_for(std::chrono::milliseconds(100)); return 0;
// download_manager.h #pragma once #include <string> #include <functional> #include <thread> #include <atomic> #include <fstream> #include <memory> #include <curl/curl.h> const std::string& error)>
find_package(CURL REQUIRED)