C++ websocket client without receive callback - c++

Question

We've a WebSocket server and clients in C#. The server is designed to slow down depending on how fast/slow the client reads and processes the messages. The C# clients reads one message at a time.
I'm looking to write a client in c++ and all the libraries I looked so far have a message handler or callback mechanism for receiving message from server.
This would mean that the client is receiving messages continuously, queue it and the client reads from the queue. This is not the behavior we're looking for. We require the client to read a message and process it and once the processing is complete, read the next message. Is there any library available we could use to achieve this?
I've so far checked cpprestsdk, websocketpp, libwebsocket

Answer 1

you can use Boost.ASIO Library.
I made a server that works with Websocket and multiple connections. Each connection uses an asynchronous way to receive data which will be handled before receiving the next message:
/**
* This method is used to read the incoming message on the WebSocket
* and handled it before reading the other message.
*/
void wscnx::read()
{
if (!is_ssl && !m_ws->is_open())
return;
else if (is_ssl && !m_wss->is_open())
return;
auto f_read = [self{shared_from_this()}](const boost::system::error_code &ec, std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
// This indicates that the session was closed
if (ec == websocket::error::closed)
{
self->close(beast::websocket::close_code::normal, ec);
return;
}
if (ec)
{
self->close(beast::websocket::close_code::abnormal, ec);
return;
}
std::string data = beast::buffers_to_string(self->m_rx_buffer.data());
self->m_rx_buffer.consume(bytes_transferred);
if (!self->m_server.expired())
{
std::string_view vdata(data.c_str());
/*************************************
Here is where the datas are handled
**************************************/
self->m_server.lock()->on_data_rx(self->m_cnx_info.id, vdata, self->cnx_info());
}
/*************************************
Read the next message in the buffer.
**************************************/
self->read();
};//lambda
if (!is_ssl)
m_ws->async_read(m_rx_buffer, f_read);
else
m_wss->async_read(m_rx_buffer, f_read);
}
In this sample the connection could be plain or secure, using SSL, both of them are using a lambda function to receive the data.
I tested this service with a JS application, on the browser and there is no problem with the sequence to attend each message.