catch "connection refused"

[farfromrefug]

I am wondering how i can catch connection refused when doing

var socket = io.connect('http://domain.com');

I cant find anything that would give me an event when it s happening.

What i see is that there no "onerror" when launching the handshake
https://github.com/LearnBoost/socket.io-client/blob/master/lib/socket.js#L151

[shimondoodkin]

in file \node_modules\socket.io\node_modules\socket.io-client\lib\socket.js
near line 164
after:
} else {
add this line:
self.publish('connect_failed', xhr.responseText, xhr, self.reconnecting );
like this::

/**
 * Performs the handshake
 *
 * @api private
 */

function empty () { };

Socket.prototype.handshake = function (fn) {
  var self = this
    , options = this.options;

  function complete (data) {
    if (data instanceof Error) {
      self.connecting = false;
      self.onError(data.message);
    } else {
      fn.apply(null, data.split(':'));
    }
  };

  var url = [
        'http' + (options.secure ? 's' : '') + ':/'
      , options.host + ':' + options.port
      , options.resource
      , io.protocol
      , io.util.query(this.options.query, 't=' + +new Date)
    ].join('/');

  if (this.isXDomain() && !io.util.ua.hasCORS) {
    var insertAt = document.getElementsByTagName('script')[0]
      , script = document.createElement('script');

    script.src = url + '&jsonp=' + io.j.length;
    insertAt.parentNode.insertBefore(script, insertAt);

    io.j.push(function (data) {
      complete(data);
      script.parentNode.removeChild(script);
    });
  } else {
    var xhr = io.util.request();

    xhr.open('GET', url, true);
    if (this.isXDomain()) {
      //xhr.withCredentials = true;
      try {xhr.withCredentials = true;}catch(e) {}
    }
    xhr.onreadystatechange = function () {
      if (xhr.readyState == 4) {
        xhr.onreadystatechange = empty;

        if (xhr.status == 200) {
          complete(xhr.responseText);
        } else if (xhr.status == 403) {
          self.onError(xhr.responseText);
        } else {
          // generally a 500 error through proxy is expected and it is ok to reconnect without error.

          // it is bad only if it is 'handshake error' or 'Protocol version not supported.' otherwise it is ok
          // decided to fire an error always for debug

          // #311 people expect that connect_failed should fire always but reconnect as usual so this is the best solution
          self.publish('connect_failed', xhr.responseText, xhr, self.reconnecting );

          /*
          if (xhr.responseText.indexOf('handshake error') !=-1
            ||xhr.responseText.indexOf('Protocol version not supported.') !=-1
             ) self.publish('connect_failed', xhr.responseText);

          if (xhr.status == 500) self.publish('connect_failed', xhr.responseText,xhr); 
          */
          self.connecting = false;            
          !self.reconnecting && self.onError(xhr.responseText);
        }
      }
    };
    xhr.send(null);
  }
};

tried to fix it in github(forked socket io client) but could not find the place in the source, seems like there is a new version in the master here, that looks different.

i use it like this to re create session for the sockets with session auth

socket.on('connect_failed', function (reason) {
if(reason.indexOf('handshake error')!=-1)
{
var o={}
o.img= new Image()
o.img.src="http://123.123.123.123:1234/keepsession.gif?"+((new Date).getTime())
o.img.onload=function(){setTimeout(function(){delete o.img;delete o;},0);}
}
console.log('unable to connect to namespace', reason);
})

https://gist.github.com/4072034 my express 3 integration of - socket.io with sessions and sessionid handshake

[shimondoodkin]

other bugs:
#214
#375

also has patch for something different #486

maybe related
#311

[farfromrefug]

Thanks a lot for your work @shimondoodkin !