cURLio

The simple C++ 17 glue between ASIO and cURL. The library is fully templated and header-only. It follows the basic principles of the ASIO design and defines async_ functions that can take different completion handlers.

On the cURL side the multi_socket approach is implemented with the cURLio::Session class which can handle thousands of requests in parallel. The current implementation of a session is synchronized via ASIO's strand mechanism in order to avoid concurrent access to the cURL handles in the background.

This library is only brings cURLio into the world of ASIO and is not meant to be easy-to-use wrapper for cURL. There are other libraries for that.

Example

The following examples uses the coroutines which were introduced in C++ 20:

#include <cURLio.hpp>

asio::io_service service{};

cURLio::Session session{ service.get_executor() };

// Create request and set options.
auto request = std::make_shared<cURLio::Request>(session);
request->set_option<CURLOPT_URL>("http://example.com");
request->set_option<CURLOPT_USERAGENT>("cURLio");

// Launches the request which will then run in the background.
auto response = co_await session.async_start(request, asio::use_awaitable);

// Read all and do something with the data.
char data[4096];
while (true) {
	const auto [ec, bytes_transferred] = co_await response->async_read_some(
	                                        asio::buffer(data), 
	                                        asio::as_tuple(asio::use_awaitable));
	if (ec) {
		break;
	}
	/* Do something. */
}

// When all data was read and the `response->async_read_some()` returned `asio::error::eof`
// the request is removed from the session and can be used again.

Configuration

The library provides two CMake targets cURLio::cURLio-asio and cURLio::cURLio-boost-asio that link to the standalone ASIO and the Boost.ASIO library respectively. The target cURLio::cURLio is an alias depending on the value of CURLIO_USE_STANDALONE_ASIO (default OFF).

Installation

git clone https://github.com/terrakuh/cURLio.git
cmake -S cURLio -B cURLio/build
cmake --install cURLio/build

And then in your CMakeLists.txt:

find_package(cURLio 0.6 REQUIRED)
target_link_libraries(my-target PRIVATE cURLio::cURLio)

Debugging

To enable logging output compile your executable with the definition CURLIO_ENABLE_LOGGING.