app.factory('$rpc', ['$syscall', '$globalTimeout', function(syscall, time) { var subscriptions = [] , configurations = [{ host: 'localhost', port: 6800 }] , timeout = null , forceNextUpdate = false; // update is implemented such that // only one syscall at max is ongoing // (i.e. serially) so should be private // to maintain that invariant var update = function() { if (!subscriptions.length) return; if (configurations.length) syscall.init(configurations.pop()); subscriptions = _.filter(subscriptions, function(e) { return !!e }); var params = _.map(subscriptions, function(s) { return { methodName: s.name, params: s.params && s.params.length ? s.params : undefined }; }); syscall.invoke({ name: 'system.multicall', params: [params], success: function(data) { // configuration worked, leave this as it is configurations = []; _.each(data.result, function(d, i) { var handle = subscriptions[i]; if (handle) { handle.cb(d); if (handle.once) { subscriptions[i] = null; } } }); if (forceNextUpdate) { forceNextUpdate = false; return update(); } timeout = setTimeout(update, time); }, error: function() { // If some proposed configurations are still in the pipeline then retry if (configurations.length) update(); else { console.log('cannot connect!!!'); timeout = setTimeout(update, time); } } }); } return { // conf can be configuration or array of configurations, // each one will be tried one after the other till success, // for all options for one conf read rpc/syscall.js configure: function(conf) { if (conf instanceof Array) configurations = conf; else configurations = [conf]; }, // syscall is done only once once: function(name, params, cb) { cb = cb || angular.noop; params = params || []; subscriptions.push({ once: true, name: 'aria2.' + name, params: params, cb: cb }); this.forceUpdate(); }, // callback is called each time with updated syscall data // after the global timeout subscribe: function(name, params, cb) { cb = cb || angular.noop; params = params || []; var handle = { once: false, name: 'aria2.' + name, params: params, cb: cb }; subscriptions.push(handle); this.forceUpdate(); return handle; }, // remove the subscribed callback by passing // the returned handle bysubscribe unsubscribe: function(handle) { var ind = subscriptions.indexOf(handle); subscriptions[ind] = null; }, // force the global syscall update forceUpdate: function() { if (timeout) { clearTimeout(timeout); timeout = null; update(); } else if (subscriptions.length) { update(); } else { // a batch call is already in progress, // wait till it returns and force the next one forceNextUpdate = true; } } }; }]);