webrtc - Google App Engine. Channel API. The provided token is invalid. -

i've been trying make application calling browser browser using webrtc. wrote simple servlet creating channel:

  prefclubchannelservletservlet extends httpservlet { public void dopost(httpservletrequest req, httpservletresponse resp)         throws ioexception {     string channelkey = req.getparameter("userid");     resp.addheader("access-control-allow-origin", "*");      channelservice channelservice = channelservicefactory.getchannelservice();     string token = channelservice.createchannel(channelkey);     resp.setcontenttype("text/plain");     resp.getwriter().println(token); } } 

i've deployed in google app engine. in web application i've got page java script, similar https://apprtc.appspot.com. in code caller calls prepare(1), , callee – prepare(0).

function prepare(ini) {     initiator = ini;     card = document.getelementbyid("card");     localvideo = document.getelementbyid("localvideo");     minivideo = document.getelementbyid("minivideo");     remotevideo = document.getelementbyid("remotevideo");     resetstatus();      console.log("try token");     gettoken(); }  function gettoken() {     var token;     if (initiator) {         var xhr = new xmlhttprequest();         var url = 'http://pref-club.appspot.com/prefclubchannelservlet?userid=gggg';         xhr.open('post', url, true);          // specify body of request contains form data         xhr.setrequestheader("content-type",             "application/x-www-form-urlencoded");          xhr.send(url);          xhr.onreadystatechange = function () {             if (xhr.readystate == 4 && xhr.status == 200) {                 token = xhr.responsetext;                 console.log("token = " + token);                 document.getelementbyid("token").value = token;                  openchannel(token);                 dogetusermedia();             }         };     } else {         token = document.getelementbyid("token").value;         console.log("token = " + token);          openchannel(token);         dogetusermedia();     } }; 

so, both caller , callee use same token open channel, , indeed open channel, got media , made rtcpeerconnection

function openchannel(channeltoken) {     console.log("opening channel.");     var channel = new goog.appengine.channel(channeltoken);     var handler = {         'onopen': onchannelopened,         'onmessage': onchannelmessage,         'onerror': onchannelerror,         'onclose': onchannelclosed     };     socket = channel.open(handler); } 

the main problem event handler onchannelmessage doesn't work. don't see s->c: in console log. callee doesn't see offer caller.

then, refreshed servlet, redeployed it, , discovered can't open channel @ all. while opening channel i'm getting uncaught error:

the provided token invalid.