Simple post example for libmicrohttpd

#include <string>
#include <vector>
#include <string>
#include <sstream>
#include <iostream>
#include <cstring>
#include <microhttpd.h>

using namespace std;

struct ConnectionData
{
    bool is_parsing;
    stringstream read_post_data;
};


int handle_request(void *cls, struct MHD_Connection *connection,
                   const char *url,
                   const char *method, const char *version,
                   const char *upload_data,
                   size_t *upload_data_size, void **con_cls)
{
    int http_code;
    string output;
    string content_type = "text/plain";

    if (strcmp(method, MHD_HTTP_METHOD_POST) == 0)
    {
        ConnectionData* connection_data = NULL;

        connection_data = static_cast<ConnectionData*>(*con_cls);
        if (NULL == connection_data)
        {
            connection_data = new ConnectionData();
            connection_data->is_parsing = false;
            *con_cls = connection_data;
        }

        if (!connection_data->is_parsing)
        {
            // First this method gets called with *upload_data_size == 0
            // just to let us know that we need to start receiving POST data
            connection_data->is_parsing = true;
            return MHD_YES;
        }
        else
        {
            if (*upload_data_size != 0)
            {
                // Receive the post data and write them into the bufffer
                connection_data->read_post_data << string(upload_data, *upload_data_size);
                *upload_data_size = 0;
                return MHD_YES;
            }
            else
            {
                // *upload_data_size == 0 so all data have been received
                output = "Received data:\n\n";
                output += connection_data->read_post_data.str();

                delete connection_data;
                connection_data = NULL;
                *con_cls = NULL;
            }
        }
    }
    else
    {
        http_code = MHD_HTTP_NOT_FOUND;
        content_type = "text/plain";
        output = "Unknown request method";
    }

    const char* output_const = output.c_str();

    struct MHD_Response *response = MHD_create_response_from_buffer(
                    strlen(output_const), (void*)output_const, MHD_RESPMEM_MUST_COPY);

    MHD_add_response_header(response, MHD_HTTP_HEADER_CONTENT_TYPE, content_type.c_str());

    int ret = MHD_queue_response(connection, http_code, response);

    MHD_destroy_response(response);

    return ret;
}

int main (int argc, char** argv)
{

    MHD_Daemon* daemon = MHD_start_daemon(
                    MHD_USE_SELECT_INTERNALLY, 8001, NULL, NULL,
                    &handle_request, NULL, MHD_OPTION_END);

    if(!daemon) {
        cerr << "Failed to start HTTP server " << endl;
        return 1;
    }

    // Handle requests until we're asked to stop
    for(;;) {
        MHD_run (daemon);
        usleep(1000*1000);
    }
    return 0;
}