Connection state with doowb/angular-pusher - angularjs

Question

I am trying to build an Angular project with Pusher using the angular-pusher wrapper. It's working well but I need to detect when the user loses internet briefly so that they can retrieve missed changes to data from my server.
It looks like the way to handle this is to reload the data on Pusher.connection.state('connected'...) but this does not seem to work with angular-pusher - I am receiving "Pusher.connection" is undefined.
Here is my code:
angular.module('respondersapp', ['doowb.angular-pusher']).
config(['PusherServiceProvider',
function(PusherServiceProvider) {
PusherServiceProvider
.setToken('Foooooooo')
.setOptions({});
}
]);
var ResponderController = function($scope, $http, Pusher) {
$scope.responders = [];
Pusher.subscribe('responders', 'status', function (item) {
// an item was updated. find it in our list and update it.
var found = false;
for (var i = 0; i < $scope.responders.length; i++) {
if ($scope.responders[i].id === item.id) {
found = true;
$scope.responders[i] = item;
break;
}
}
if (!found) {
$scope.responders.push(item);
}
});
Pusher.subscribe('responders', 'unavail', function(item) {
$scope.responders.splice($scope.responders.indexOf(item), 1);
});
var retrieveResponders = function () {
// get a list of responders from the api located at '/api/responders'
console.log('getting responders');
$http.get('/app/dashboard/avail-responders')
.success(function (responders) {
$scope.responders = responders;
});
};
$scope.updateItem = function (item) {
console.log('updating item');
$http.post('/api/responders', item);
};
// load the responders
retrieveResponders();
};
Under this setup how would I go about monitoring connection state? I'm basically trying to replicate the Firebase "catch up" functionality for spotty connections, Firebase was not working overall for me, too confusing trying to manage multiple data sets (not looking to replace back-end at all).
Thanks!

Answer 1

It looks like the Pusher dependency only exposes subscribe and unsubscribe. See:
https://github.com/doowb/angular-pusher/blob/gh-pages/angular-pusher.js#L86
However, if you access the PusherService you get access to the Pusher instance (the one provided by the Pusher JS library) using PusherService.then. See:
https://github.com/doowb/angular-pusher/blob/gh-pages/angular-pusher.js#L91
I'm not sure why the PusherService provides a level of abstraction and why it doesn't just return the pusher instance. It's probably so that it can add some of the Angular specific functionality ($rootScope.$broadcast and $rootScope.$digest).
Maybe you can set the PusherService as a dependency and access the pusher instance using the following?
PusherService.then(function (pusher) {
var state = pusher.connection.state;
});

Answer 2

To clarify #leggetters answer, you might do something like:
app.controller("MyController", function(PusherService) {
PusherService.then(function(pusher) {
pusher.connection.bind("state_change", function(states) {
console.log("Pusher's state changed from %o to %o", states.previous, states.current);
});
});
});
Also note that pusher-js (which angular-pusher uses) has activityTimeout and pongTimeout configuration to tweak the connection state detection.
From my limited experiments, connection states can't be relied on. With the default values, you can go offline for many seconds and then back online without them being any the wiser.
Even if you lower the configuration values, someone could probably drop offline for just a millisecond and miss a message if they're unlucky.