Using event loop

It's possible to perform heavy operations from another thread and perform response asynchronously. For this event loop is introduced.

Please note, to make posting tasks from another thread possible, ngrest must be compiled with option WITH_THREAD_LOCK=1. You must have this environment variable when you installing ngrest.

Currently event loop is only supported with simple ngrest server.

Long synchronous operation can be performed without blocking event look like that:

#include <chrono>
#include <thread>

void ExampleService::echoASync(const std::string& value, ngrest::Callback<const std::string&>& callback)
{
    // take callback by reference because it's allocated in mempool
    // take argument(s) by value because it's allocated in stack
    std::thread([&callback, value]{
        // perform some long synchronous operation
        std::this_thread::sleep_for(std::chrono::seconds(1));
        // post to event loop
        Handler::post([&callback, value]{
            // this will be executed from main thread
            callback.success("You said " + value);
        });
    })
    .detach();
}

Please note, you must take arguments by value and callback by reference else UB may occur.