WebResourceLoader class

IMPORTANT: The class cannot download from https:// sources because OpenSSL is turned off in curl CMakeLists.txt

openVulkanoCpp/Host/WebResourceLoader.cpp

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+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include "WebResourceLoader.hpp"
+#include "IO/AppFolders.hpp"
+#include "Base/Utils.hpp"
+
+#include <fstream>
+#include <sstream>
+#include <curl/curl.h>
+
+namespace OpenVulkano
+{
+	namespace
+	{
+		size_t curlDownloader(void* contents, size_t size, size_t memBlockCount, void* userData)
+		{
+			size_t totalSize = size * memBlockCount;
+			std::vector<char>* buffer = static_cast<std::vector<char>*>(userData);
+			buffer->insert(buffer->end(), static_cast<char*>(contents), static_cast<char*>(contents) + totalSize);
+			return totalSize;
+		}
+	}
+
+	WebResourceLoader::WebResourceLoader()
+	{
+		m_cacheDirectory = AppFolders::GetAppCacheDir() / "resources";
+		std::filesystem::create_directories(m_cacheDirectory);
+		curl_global_init(CURL_GLOBAL_DEFAULT);
+	}
+
+	WebResourceLoader::~WebResourceLoader() { curl_global_cleanup(); }
+
+	std::filesystem::path WebResourceLoader::GetCacheFilePath(const std::string& url)
+	{
+		size_t hash = std::hash<std::string> {}(url);
+		std::string hashedUrl = std::to_string(hash);
+
+		return m_cacheDirectory / hashedUrl;
+	}
+
+	Array<char> WebResourceLoader::DownloadResource(const std::string& url)
+	{
+		std::vector<char> buffer;
+
+		CURL* curl = curl_easy_init();
+		if (curl)
+		{
+			curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
+			curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &curlDownloader);
+			curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
+
+#ifdef __APPLE__
+			curl_easy_setopt(curl, CURLOPT_SSLENGINE, "DarwinSSL");
+#endif
+
+			CURLcode result = curl_easy_perform(curl);
+			if (result != CURLE_OK)
+			{
+				curl_easy_cleanup(curl);
+				throw std::runtime_error("Failed to download resource: '" + url + "' - " + curl_easy_strerror(result));
+			}
+			curl_easy_cleanup(curl);
+		}
+
+		std::filesystem::path cacheFilePath = GetCacheFilePath(url);
+		std::ofstream file(cacheFilePath, std::ios::binary);
+		file.write(buffer.data(), buffer.size());
+		return Array<char>(buffer);
+	}
+
+	bool WebResourceLoader::IsUrl(const std::string& str)
+	{
+		return str.find("http://") == 0 || str.find("https://") == 0 || str.find("ftp://") == 0;
+	}
+
+	Array<char> WebResourceLoader::GetResource(const std::string& resourceName)
+	{
+		if (IsUrl(resourceName))
+		{
+			std::filesystem::path cacheFilePath = GetCacheFilePath(resourceName);
+			if (std::filesystem::exists(cacheFilePath)) { return Utils::ReadFile(cacheFilePath.string()); }
+			else { return DownloadResource(resourceName); }
+		}
+		throw std::runtime_error("Resource name is not a valid URL");
+	}
+}