Question

I want to program a HTTP client with boost. I could use the asynchronous model if I manage to do the following:

• In a first step, send the request to the server.
• In a second step, either read the the response that has already arrived or wait synchronously until it arrives.

This is a class that looks similar to what I have produce:

class HTTPClient {
public:
    void sendTheRequest(...) {
        // Send the HTTP request
    }

    std::string getTheResponse(...) {
        // return the already (asynchronously) received response, or wait for it
        // in this function
    }
}

Can someone point out how to realize this? I fear I am lacking the knowledge in boost.

Edit for clarification: The method sendTheRequest will be called at a point. Maybe directly after it getTheResponse will be called, but this can also happen some (milli)seconds later. Thats why I want to send the request asynchronously, but need to wait for it synchronously too.

Answer 1

Mabye a bit late, but I think this should do it. std::future::get returns the value of the send_request_function or waits if that didn’t return yet and returns it after it has completed.

class HTTPClient {
public:
    void sendTheRequest(...) {
        // Send the HTTP request
        f = std::async(std::launch::async, send_request_function, args ...);

    }

    std::string getTheResponse(...) {
        // return the already (asynchronously) received response, or wait for it
        // in this function
        return f.get();

    }
private:
    std::future<std::string> f;

}