cpp

C++ implementation of the Foxglove WebSocket protocol

Instructions

• Run make build
• Run make example_server_protobuf or make example_server_flatbuffers

For websocket throughput testing, you can use make example_server_perf_test and connect with https://foxglove.github.io/ws-protocol or with make example_client_perf_test.

Thread safety

The C++ foxglove websocket implementation uses websocketpp which is thread safe. However, you cannot send data through the websocket inside a connection handler callback of the same websocket connection. For example, if you want to implement message latching, you might want to flush buffered messages upon client connection (using subscribeHandler). But nothing would get sent out inside the callback thread. To fix this, you can simply spin up a new thread. You could do something like:

auto server_ptr = foxglove::ServerFactory::createServer<websocketpp::connection_hdl>(server_name, log_handler, options);

// Setup handlers.
foxglove::ServerHandlers<foxglove::ConnHandle> hdlrs;
hdlrs.subscribeHandler = [&](foxglove::ChannelId channel_id, foxglove::ConnHandle) {
    // Spin up new thread here to publish messages through the same websocket
    std::thread t([&, channel_id]() {
        flush_buffered_messages(channel_id);
    });
    t.detach();
};

server_ptr->setHandlers(std::move(hdlrs));
server_ptr->start(ip, port);