Use t6-gsc-utils as a base.

src/utils/http.cpp

@@ -0,0 +1,101 @@
+#include <stdinc.hpp>
+#include "http.hpp"
+#include <curl/curl.h>
+#include <gsl/gsl>
+
+#pragma comment(lib, "ws2_32.lib")
+
+namespace utils::http
+{
+	namespace
+	{
+		struct progress_helper
+		{
+			const std::function<void(size_t)>* callback{};
+			std::exception_ptr exception{};
+		};
+
+		int progress_callback(void* clientp, const curl_off_t /*dltotal*/, const curl_off_t dlnow, const curl_off_t /*ultotal*/, const curl_off_t /*ulnow*/)
+		{
+			auto* helper = static_cast<progress_helper*>(clientp);
+
+			try
+			{
+				if (*helper->callback)
+				{
+					(*helper->callback)(dlnow);
+				}
+			}
+			catch (...)
+			{
+				helper->exception = std::current_exception();
+				return -1;
+			}
+
+			return 0;
+		}
+
+		size_t write_callback(void* contents, const size_t size, const size_t nmemb, void* userp)
+		{
+			auto* buffer = static_cast<std::string*>(userp);
+
+			const auto total_size = size * nmemb;
+			buffer->append(static_cast<char*>(contents), total_size);
+			return total_size;
+		}
+	}
+
+	std::optional<std::string> get_data(const std::string& url, const headers& headers, const std::function<void(size_t)>& callback)
+	{
+		curl_slist* header_list = nullptr;
+		auto* curl = curl_easy_init();
+		if (!curl)
+		{
+			return {};
+		}
+
+		auto _ = gsl::finally([&]()
+		{
+			curl_slist_free_all(header_list);
+			curl_easy_cleanup(curl);
+		});
+
+		for (const auto& header : headers)
+		{
+			auto data = header.first + ": " + header.second;
+			header_list = curl_slist_append(header_list, data.data());
+		}
+
+		std::string buffer{};
+		progress_helper helper{};
+		helper.callback = &callback;
+
+		curl_easy_setopt(curl, CURLOPT_HTTPHEADER, header_list);
+		curl_easy_setopt(curl, CURLOPT_URL, url.data());
+		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
+		curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
+		curl_easy_setopt(curl, CURLOPT_XFERINFOFUNCTION, progress_callback);
+		curl_easy_setopt(curl, CURLOPT_XFERINFODATA, &helper);
+		curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 0);
+
+		if (curl_easy_perform(curl) == CURLE_OK)
+		{
+			return {std::move(buffer)};
+		}
+
+		if (helper.exception)
+		{
+			std::rethrow_exception(helper.exception);
+		}
+
+		return {};
+	}
+
+	std::future<std::optional<std::string>> get_data_async(const std::string& url, const headers& headers)
+	{
+		return std::async(std::launch::async, [url, headers]()
+		{
+			return get_data(url, headers);
+		});
+	}
+}