Post application/json in gjs

postjson.js

const Lang = imports.lang;
const Soup = imports.gi.Soup;
 
let _session = new Soup.SessionAsync(); 

function POSTJSON(url, params, callback) { 
    log('post started');
    let request = Soup.Message.new('POST', url); 
    log('req created');
    let _params = JSON.stringify(params)         
    log('params created');
 
    request.set_request('application/json',                  
                    Soup.MemoryUse.COPY, 
                    _params, 
                    _params.length); 
 
    _session.queue_message(request, Lang.bind(this, 
                                             function(session, message) { 
                                                callback(message.status_code, request.response_body.data);
                                             } 
                         ) 
        );
    log('message qd');
} 


// Standalone script only section
const Mainloop = imports.mainloop;
POSTJSON('http://example.org/create', {'foo': 'bar'}, function(code, data) { log('post done'); log(code); log(data); Mainloop.quit(true); });
Mainloop.run(true);