xmpp.chapril.org-conversejs/src/converse-core.js

// Converse.js (A browser based XMPP chat client)
// http://conversejs.org
//
// Copyright (c) 2012-2017, Jan-Carel Brand <jc@opkode.com>
// Licensed under the Mozilla Public License (MPLv2)
//
/*global Backbone, define, window, document */

(function (root, factory) {
    define([
        "sizzle",
        "jquery",
        "lodash",
        "polyfill",
        "locales",
        "utils",
        "moment_with_locales",
        "strophe",
        "pluggable",
        "strophe.disco",
        "backbone.browserStorage",
        "backbone.overview",
    ], factory);
}(this, function (sizzle, $, _, dummy, locales, utils, moment, Strophe, pluggable) {
    /*
     * Cannot use this due to Safari bug.
     * See https://github.com/jcbrand/converse.js/issues/196
     */
    // "use strict";

    // Strophe globals
    var $build = Strophe.$build;
    var $iq = Strophe.$iq;
    var $pres = Strophe.$pres;
    var b64_sha1 = Strophe.SHA1.b64_sha1;
    Strophe = Strophe.Strophe;

    // Use Mustache style syntax for variable interpolation
    /* Configuration of Lodash templates (this config is distinct to the
     * config of requirejs-tpl in main.js). This one is for normal inline templates.
     */
    _.templateSettings = {
        evaluate : /\{\[([\s\S]+?)\]\}/g,
        interpolate : /\{\{([\s\S]+?)\}\}/g
    };

    var _converse = {};
    _converse.templates = {};
    _.extend(_converse, Backbone.Events);
    _converse.promises = {
        'cachedRoster': new $.Deferred(),
        'chatBoxesFetched': new $.Deferred(),
        'connected': new $.Deferred(),
        'pluginsInitialized': new $.Deferred(),
        'roster': new $.Deferred(),
        'rosterContactsFetched': new $.Deferred(),
        'rosterGroupsFetched': new $.Deferred(),
        'rosterInitialized': new $.Deferred(),
        'statusInitialized': new $.Deferred()
    };
    _converse.emit = function (name) {
        _converse.trigger.apply(this, arguments);
        var promise = _converse.promises[name];
        if (!_.isUndefined(promise)) {
            promise.resolve();
        }
    };

    _converse.core_plugins = [
        'converse-bookmarks',
        'converse-chatview',
        'converse-controlbox',
        'converse-core',
        'converse-dragresize',
        'converse-headline',
        'converse-mam',
        'converse-minimize',
        'converse-muc',
        'converse-notification',
        'converse-otr',
        'converse-ping',
        'converse-register',
        'converse-rosterview',
        'converse-vcard'
    ];

    // Make converse pluggable
    pluggable.enable(_converse, '_converse', 'pluggable');

    // Module-level constants
    _converse.STATUS_WEIGHTS = {
        'offline':      6,
        'unavailable':  5,
        'xa':           4,
        'away':         3,
        'dnd':          2,
        'chat':         1, // We currently don't differentiate between "chat" and "online"
        'online':       1
    };
    _converse.ANONYMOUS  = "anonymous";
    _converse.CLOSED = 'closed';
    _converse.EXTERNAL = "external";
    _converse.LOGIN = "login";
    _converse.LOGOUT = "logout";
    _converse.OPENED = 'opened';
    _converse.PREBIND = "prebind";

    var PRETTY_CONNECTION_STATUS = {
        0: 'ERROR',
        1: 'CONNECTING',
        2: 'CONNFAIL',
        3: 'AUTHENTICATING',
        4: 'AUTHFAIL',
        5: 'CONNECTED',
        6: 'DISCONNECTED',
        7: 'DISCONNECTING',
        8: 'ATTACHED',
        9: 'REDIRECT'
    };

    var DEFAULT_IMAGE_TYPE = 'image/png';
    var DEFAULT_IMAGE = "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";

    _converse.log = function (txt, level) {
        var logger;
        if (_.isUndefined(console) || _.isUndefined(console.log)) {
            logger = { log: _.noop, error: _.noop };
        } else {
            logger = console;
        }
        if (_converse.debug) {
            if (level === 'error') {
                logger.log('ERROR: '+txt);
            } else {
                logger.log(txt);
            }
        }
    };


    _converse.initialize = function (settings, callback) {
        "use strict";
        settings = !_.isUndefined(settings) ? settings : {};
        var init_deferred = new $.Deferred();

        if (!_.isUndefined(_converse.chatboxes)) {
            // Looks like _converse.initialized was called again without logging
            // out or disconnecting in the previous session.
            // This happens in tests. We therefore first clean up.
            _converse.connection.reset();
            _converse.off();
            _converse.stopListening();
            _converse._tearDown();
        }

        var unloadevent;
        if ('onpagehide' in window) {
            // Pagehide gets thrown in more cases than unload. Specifically it
            // gets thrown when the page is cached and not just
            // closed/destroyed. It's the only viable event on mobile Safari.
            // https://www.webkit.org/blog/516/webkit-page-cache-ii-the-unload-event/
            unloadevent = 'pagehide';
        } else if ('onbeforeunload' in window) {
            unloadevent = 'beforeunload';
        } else if ('onunload' in window) {
            unloadevent = 'unload';
        }

        // Logging
        Strophe.log = function (level, msg) { _converse.log(level+' '+msg, level); };
        Strophe.error = function (msg) { _converse.log(msg, 'error'); };

        // Add Strophe Namespaces
        Strophe.addNamespace('CARBONS', 'urn:xmpp:carbons:2');
        Strophe.addNamespace('CHATSTATES', 'http://jabber.org/protocol/chatstates');
        Strophe.addNamespace('CSI', 'urn:xmpp:csi:0');
        Strophe.addNamespace('ROSTERX', 'http://jabber.org/protocol/rosterx');
        Strophe.addNamespace('XFORM', 'jabber:x:data');
        Strophe.addNamespace('NICK', 'http://jabber.org/protocol/nick');
        Strophe.addNamespace('HINTS', 'urn:xmpp:hints');
        Strophe.addNamespace('PUBSUB', 'http://jabber.org/protocol/pubsub');

        // Instance level constants
        this.TIMEOUTS = { // Set as module attr so that we can override in tests.
            'PAUSED':     10000,
            'INACTIVE':   90000
        };

        // XEP-0085 Chat states
        // http://xmpp.org/extensions/xep-0085.html
        this.INACTIVE = 'inactive';
        this.ACTIVE = 'active';
        this.COMPOSING = 'composing';
        this.PAUSED = 'paused';
        this.GONE = 'gone';

        // Detect support for the user's locale
        // ------------------------------------
        locales = _.isUndefined(locales) ? {} : locales;
        this.isConverseLocale = function (locale) {
            return !_.isUndefined(locales[locale]);
        };
        this.isMomentLocale = function (locale) { return moment.locale() !== moment.locale(locale); };
        if (!moment.locale) { //moment.lang is deprecated after 2.8.1, use moment.locale instead
            moment.locale = moment.lang;
        }
        moment.locale(utils.detectLocale(this.isMomentLocale));
        if (_.includes(_.keys(locales), settings.i18n)) {
            settings.i18n = locales[settings.i18n];
        }
        this.i18n = settings.i18n ? settings.i18n : locales[utils.detectLocale(this.isConverseLocale)] || {};

        // Translation machinery
        // ---------------------
        var __ = _converse.__ = utils.__.bind(_converse);
        _converse.___ = utils.___;
        var DESC_GROUP_TOGGLE = __('Click to hide these contacts');

        // Default configuration values
        // ----------------------------
        this.default_settings = {
            allow_contact_requests: true,
            allow_non_roster_messaging: false,
            animate: true,
            authentication: 'login', // Available values are "login", "prebind", "anonymous" and "external".
            auto_away: 0, // Seconds after which user status is set to 'away'
            auto_login: false, // Currently only used in connection with anonymous login
            auto_reconnect: false,
            auto_subscribe: false,
            auto_xa: 0, // Seconds after which user status is set to 'xa'
            blacklisted_plugins: [],
            bosh_service_url: undefined,
            connection_options: {},
            credentials_url: null, // URL from where login credentials can be fetched
            csi_waiting_time: 0, // Support for XEP-0352. Seconds before client is considered idle and CSI is sent out.
            debug: false,
            default_state: 'online',
            expose_rid_and_sid: false,
            filter_by_resource: false,
            forward_messages: false,
            hide_offline_users: false,
            include_offline_state: false,
            jid: undefined,
            keepalive: false,
            locked_domain: undefined,
            message_carbons: false,
            message_storage: 'session',
            password: undefined,
            prebind_url: null,
            rid: undefined,
            roster_groups: false,
            show_only_online_users: false,
            sid: undefined,
            storage: 'session',
            strict_plugin_dependencies: false,
            synchronize_availability: true,
            websocket_url: undefined,
            whitelisted_plugins: [],
            xhr_custom_status: false,
            xhr_custom_status_url: '',
        };
        _.assignIn(this, this.default_settings);
        // Allow only whitelisted configuration attributes to be overwritten
        _.assignIn(this, _.pick(settings, _.keys(this.default_settings)));

        // BBB
        if (this.prebind === true) { this.authentication = _converse.PREBIND; }

        if (this.authentication === _converse.ANONYMOUS) {
            if (this.auto_login && !this.jid) {
                throw new Error("Config Error: you need to provide the server's " +
                      "domain via the 'jid' option when using anonymous " +
                      "authentication with auto_login.");
            }
        }

        $.fx.off = !this.animate;

        // Module-level variables
        // ----------------------
        this.callback = callback || _.noop;
        /* When reloading the page:
         * For new sessions, we need to send out a presence stanza to notify
         * the server/network that we're online.
         * When re-attaching to an existing session (e.g. via the keepalive
         * option), we don't need to again send out a presence stanza, because
         * it's as if "we never left" (see onConnectStatusChanged).
         * https://github.com/jcbrand/converse.js/issues/521
         */
        this.send_initial_presence = true;
        this.msg_counter = 0;
        this.user_settings = settings; // Save the user settings so that they can be used by plugins

        // Module-level functions
        // ----------------------
        this.wrappedChatBox = function (chatbox) {
            /* Wrap a chatbox for outside consumption (i.e. so that it can be
             * returned via the API.
             */
            if (!chatbox) { return; }
            var view = _converse.chatboxviews.get(chatbox.get('id'));
            return {
                'close': view.close.bind(view),
                'focus': view.focus.bind(view),
                'get': chatbox.get.bind(chatbox),
                'open': view.show.bind(view),
                'set': chatbox.set.bind(chatbox)
            };
        };

        this.generateResource = function () {
            return '/converse.js-' + Math.floor(Math.random()*139749825).toString();
        };

        this.sendCSI = function (stat) {
            /* Send out a Chat Status Notification (XEP-0352)
             *
             * Parameters:
             *  (String) stat: The user's chat status
             */
            /* Send out a Chat Status Notification (XEP-0352) */
            // XXX if (converse.features[Strophe.NS.CSI] || true) {
            _converse.connection.send($build(stat, {xmlns: Strophe.NS.CSI}));
            _converse.inactive = (stat === _converse.INACTIVE) ? true : false;
        };

        this.onUserActivity = function () {
            /* Resets counters and flags relating to CSI and auto_away/auto_xa */
            if (_converse.idle_seconds > 0) {
                _converse.idle_seconds = 0;
            }
            if (!_converse.connection.authenticated) {
                // We can't send out any stanzas when there's no authenticated connection.
                // converse can happen when the connection reconnects.
                return;
            }
            if (_converse.inactive) {
                _converse.sendCSI(_converse.ACTIVE);
            }
            if (_converse.auto_changed_status === true) {
                _converse.auto_changed_status = false;
                // XXX: we should really remember the original state here, and
                // then set it back to that...
                _converse.xmppstatus.setStatus(_converse.default_state);
            }
        };

        this.onEverySecond = function () {
            /* An interval handler running every second.
             * Used for CSI and the auto_away and auto_xa features.
             */
            if (!_converse.connection.authenticated) {
                // We can't send out any stanzas when there's no authenticated connection.
                // This can happen when the connection reconnects.
                return;
            }
            var stat = _converse.xmppstatus.getStatus();
            _converse.idle_seconds++;
            if (_converse.csi_waiting_time > 0 &&
                    _converse.idle_seconds > _converse.csi_waiting_time &&
                    !_converse.inactive) {
                _converse.sendCSI(_converse.INACTIVE);
            }
            if (_converse.auto_away > 0 &&
                    _converse.idle_seconds > _converse.auto_away &&
                    stat !== 'away' && stat !== 'xa') {
                _converse.auto_changed_status = true;
                _converse.xmppstatus.setStatus('away');
            } else if (_converse.auto_xa > 0 &&
                    _converse.idle_seconds > _converse.auto_xa && stat !== 'xa') {
                _converse.auto_changed_status = true;
                _converse.xmppstatus.setStatus('xa');
            }
        };

        this.registerIntervalHandler = function () {
            /* Set an interval of one second and register a handler for it.
             * Required for the auto_away, auto_xa and csi_waiting_time features.
             */
            if (_converse.auto_away < 1 && _converse.auto_xa < 1 && _converse.csi_waiting_time < 1) {
                // Waiting time of less then one second means features aren't used.
                return;
            }
            _converse.idle_seconds = 0;
            _converse.auto_changed_status = false; // Was the user's status changed by _converse.js?
            $(window).on('click mousemove keypress focus'+unloadevent, _converse.onUserActivity);
            _converse.everySecondTrigger = window.setInterval(_converse.onEverySecond, 1000);
        };

        this.giveFeedback = function (subject, klass, message) {
            $('.conn-feedback').each(function (idx, el) {
                el.classList.add('conn-feedback');
                el.textContent = subject;
                if (klass) {
                    el.classList.add(klass);
                } else {
                    el.classList.remove('error');
                }
            });
            _converse.emit('feedback', {
                'klass': klass,
                'message': message,
                'subject': subject
            });
        };

        this.rejectPresenceSubscription = function (jid, message) {
            /* Reject or cancel another user's subscription to our presence updates.
             *
             *  Parameters:
             *    (String) jid - The Jabber ID of the user whose subscription
             *      is being canceled.
             *    (String) message - An optional message to the user
             */
            var pres = $pres({to: jid, type: "unsubscribed"});
            if (message && message !== "") { pres.c("status").t(message); }
            _converse.connection.send(pres);
        };

        this.reconnect = _.debounce(function () {
            _converse.log('RECONNECTING');
            _converse.log('The connection has dropped, attempting to reconnect.');
            _converse.giveFeedback(
                __("Reconnecting"),
                'warn',
                __('The connection has dropped, attempting to reconnect.')
            );
            _converse.connection.reconnecting = true;
            _converse._tearDown();
            _converse.logIn(null, true);
        }, 3000, {'leading': true});

        this.disconnect = function () {
            _converse.log('DISCONNECTED');
            delete _converse.connection.reconnecting;
            _converse._tearDown();
            _converse.chatboxviews.closeAllChatBoxes();
            _converse.emit('disconnected');
        };

        this.onDisconnected = function () {
            /* Gets called once strophe's status reaches Strophe.Status.DISCONNECTED.
             * Will either start a teardown process for converse.js or attempt
             * to reconnect.
             */
            if (_converse.disconnection_cause === Strophe.Status.AUTHFAIL) {
                if (_converse.credentials_url && _converse.auto_reconnect) {
                    /* In this case, we reconnect, because we might be receiving
                     * expirable tokens from the credentials_url.
                     */
                    _converse.emit('will-reconnect');
                    return _converse.reconnect();
                } else {
                    return _converse.disconnect();
                }
            } else if (_converse.disconnection_cause === _converse.LOGOUT ||
                    _converse.disconnection_reason === "host-unknown" ||
                    !_converse.auto_reconnect) {
                return _converse.disconnect();
            }
            _converse.emit('will-reconnect');
            _converse.reconnect();
        };

        this.setDisconnectionCause = function (cause, reason, override) {
            /* Used to keep track of why we got disconnected, so that we can
             * decide on what the next appropriate action is (in onDisconnected)
             */
            if (_.isUndefined(cause)) {
                delete _converse.disconnection_cause;
                delete _converse.disconnection_reason;
            } else if (_.isUndefined(_converse.disconnection_cause) || override) {
                _converse.disconnection_cause = cause;
                _converse.disconnection_reason = reason;
            }
        };

        this.onConnectStatusChanged = function (status, condition) {
            /* Callback method called by Strophe as the Strophe.Connection goes
             * through various states while establishing or tearing down a
             * connection.
             */
            _converse.log("Status changed to: "+PRETTY_CONNECTION_STATUS[status]);
            if (status === Strophe.Status.CONNECTED || status === Strophe.Status.ATTACHED) {
                // By default we always want to send out an initial presence stanza.
                _converse.send_initial_presence = true;
                _converse.setDisconnectionCause();
                if (_converse.connection.reconnecting) {
                    _converse.log(status === Strophe.Status.CONNECTED ? 'Reconnected' : 'Reattached');
                    _converse.onConnected(true);
                } else {
                    _converse.log(status === Strophe.Status.CONNECTED ? 'Connected' : 'Attached');
                    if (_converse.connection.restored) {
                        // No need to send an initial presence stanza when
                        // we're restoring an existing session.
                        _converse.send_initial_presence = false;
                    }
                    _converse.onConnected();
                }
            } else if (status === Strophe.Status.DISCONNECTED) {
                _converse.setDisconnectionCause(status, condition);
                _converse.onDisconnected();
            } else if (status === Strophe.Status.ERROR) {
                _converse.giveFeedback(
                    __('Connection error'), 'error',
                    __('An error occurred while connecting to the chat server.')
                );
            } else if (status === Strophe.Status.CONNECTING) {
                _converse.giveFeedback(__('Connecting'));
            } else if (status === Strophe.Status.AUTHENTICATING) {
                _converse.giveFeedback(__('Authenticating'));
            } else if (status === Strophe.Status.AUTHFAIL) {
                _converse.giveFeedback(__('Authentication Failed'), 'error');
                _converse.setDisconnectionCause(status, condition, true);
                _converse.onDisconnected();
            } else if (status === Strophe.Status.CONNFAIL) {
                _converse.giveFeedback(
                    __('Connection failed'), 'error',
                    __('An error occurred while connecting to the chat server: '+condition)
                );
                _converse.setDisconnectionCause(status, condition);
            } else if (status === Strophe.Status.DISCONNECTING) {
                _converse.setDisconnectionCause(status, condition);
            }
        };

        this.updateMsgCounter = function () {
            if (this.msg_counter > 0) {
                if (document.title.search(/^Messages \(\d+\) /) === -1) {
                    document.title = "Messages (" + this.msg_counter + ") " + document.title;
                } else {
                    document.title = document.title.replace(/^Messages \(\d+\) /, "Messages (" + this.msg_counter + ") ");
                }
            } else if (document.title.search(/^Messages \(\d+\) /) !== -1) {
                document.title = document.title.replace(/^Messages \(\d+\) /, "");
            }
        };

        this.incrementMsgCounter = function () {
            this.msg_counter += 1;
            this.updateMsgCounter();
        };

        this.clearMsgCounter = function () {
            this.msg_counter = 0;
            this.updateMsgCounter();
        };

        this.initStatus = function () {
            var deferred = new $.Deferred();
            this.xmppstatus = new this.XMPPStatus();
            var id = b64_sha1('converse.xmppstatus-'+_converse.bare_jid);
            this.xmppstatus.id = id; // Appears to be necessary for backbone.browserStorage
            this.xmppstatus.browserStorage = new Backbone.BrowserStorage[_converse.storage](id);
            this.xmppstatus.fetch({
                success: deferred.resolve,
                error: deferred.resolve
            });
            _converse.emit('statusInitialized');
            return deferred.promise();
        };

        this.initSession = function () {
            this.session = new this.Session();
            var id = b64_sha1('converse.bosh-session');
            this.session.id = id; // Appears to be necessary for backbone.browserStorage
            this.session.browserStorage = new Backbone.BrowserStorage[_converse.storage](id);
            this.session.fetch();
        };

        this.clearSession = function () {
            if (!_.isUndefined(this.roster)) {
                this.roster.browserStorage._clear();
            }
            this.session.browserStorage._clear();
        };

        this.logOut = function () {
            _converse.setDisconnectionCause(_converse.LOGOUT, undefined, true);
            if (!_.isUndefined(_converse.connection)) {
                _converse.connection.disconnect();
            }
            _converse.chatboxviews.closeAllChatBoxes();
            _converse.clearSession();
            _converse._tearDown();
            _converse.emit('logout');
        };

        this.saveWindowState = function (ev, hidden) {
            // XXX: eventually we should be able to just use
            // document.visibilityState (when we drop support for older
            // browsers).
            var state;
            var v = "visible", h = "hidden",
                event_map = {
                    'focus': v,
                    'focusin': v,
                    'pageshow': v,
                    'blur': h,
                    'focusout': h,
                    'pagehide': h
                };
            ev = ev || document.createEvent('Events');
            if (ev.type in event_map) {
                state = event_map[ev.type];
            } else {
                state = document[hidden] ? "hidden" : "visible";
            }
            if (state  === 'visible') {
                _converse.clearMsgCounter();
            }
            _converse.windowState = state;
        };

        this.registerGlobalEventHandlers = function () {
            // Taken from:
            // http://stackoverflow.com/questions/1060008/is-there-a-way-to-detect-if-a-browser-window-is-not-currently-active
            var hidden = "hidden";
            // Standards:
            if (hidden in document) {
                document.addEventListener("visibilitychange", _.partial(_converse.saveWindowState, _, hidden));
            } else if ((hidden = "mozHidden") in document) {
                document.addEventListener("mozvisibilitychange", _.partial(_converse.saveWindowState, _, hidden));
            } else if ((hidden = "webkitHidden") in document) {
                document.addEventListener("webkitvisibilitychange", _.partial(_converse.saveWindowState, _, hidden));
            } else if ((hidden = "msHidden") in document) {
                document.addEventListener("msvisibilitychange", _.partial(_converse.saveWindowState, _, hidden));
            } else if ("onfocusin" in document) {
                // IE 9 and lower:
                document.onfocusin = document.onfocusout = _.partial(_converse.saveWindowState, _, hidden);
            } else {
                // All others:
                window.onpageshow = window.onpagehide = window.onfocus = window.onblur = _.partial(_converse.saveWindowState, _, hidden);
            }
            // set the initial state (but only if browser supports the Page Visibility API)
            if( document[hidden] !== undefined ) {
                _.partial(_converse.saveWindowState, _, hidden)({type: document[hidden] ? "blur" : "focus"});
            }
        };

        this.enableCarbons = function () {
            /* Ask the XMPP server to enable Message Carbons
             * See XEP-0280 https://xmpp.org/extensions/xep-0280.html#enabling
             */
            if (!this.message_carbons || this.session.get('carbons_enabled')) {
                return;
            }
            var carbons_iq = new Strophe.Builder('iq', {
                from: this.connection.jid,
                id: 'enablecarbons',
                type: 'set'
              })
              .c('enable', {xmlns: Strophe.NS.CARBONS});
            this.connection.addHandler(function (iq) {
                if (iq.querySelectorAll('error').length > 0) {
                    _converse.log('ERROR: An error occured while trying to enable message carbons.');
                } else {
                    this.session.save({carbons_enabled: true});
                    _converse.log('Message carbons have been enabled.');
                }
            }.bind(this), null, "iq", null, "enablecarbons");
            this.connection.send(carbons_iq);
        };

        this.initRoster = function () {
            /* Initialize the Bakcbone collections that represent the contats
             * roster and the roster groups.
             */
            _converse.roster = new _converse.RosterContacts();
            _converse.roster.browserStorage = new Backbone.BrowserStorage.session(
                b64_sha1('converse.contacts-'+_converse.bare_jid));
            _converse.rostergroups = new _converse.RosterGroups();
            _converse.rostergroups.browserStorage = new Backbone.BrowserStorage.session(
                b64_sha1('converse.roster.groups'+_converse.bare_jid));
            _converse.emit('rosterInitialized');
        };

        this.populateRoster = function () {
            /* Fetch all the roster groups, and then the roster contacts.
             * Emit an event after fetching is done in each case.
             */
            _converse.rostergroups.fetchRosterGroups().then(function () {
                _converse.emit('rosterGroupsFetched');
                _converse.roster.fetchRosterContacts().then(function () {
                    _converse.emit('rosterContactsFetched');
                    _converse.sendInitialPresence();
                });
            });
        };

        this.unregisterPresenceHandler = function () {
            if (!_.isUndefined(_converse.presence_ref)) {
                _converse.connection.deleteHandler(_converse.presence_ref);
                delete _converse.presence_ref;
            }
        };

        this.registerPresenceHandler = function () {
            _converse.unregisterPresenceHandler();
            _converse.presence_ref = _converse.connection.addHandler(
                function (presence) {
                    _converse.roster.presenceHandler(presence);
                    return true;
                }, null, 'presence', null);
        };


        this.sendInitialPresence = function () {
            if (_converse.send_initial_presence) {
                _converse.xmppstatus.sendPresence();
            }
        };

        this.onStatusInitialized = function (reconnecting) {
            /* Continue with session establishment (e.g. fetching chat boxes,
             * populating the roster etc.) necessary once the connection has
             * been established.
             */
            if (reconnecting) {
                // No need to recreate the roster, otherwise we lose our
                // cached data. However we still emit an event, to give
                // event handlers a chance to register views for the
                // roster and its groups, before we start populating.
                _converse.emit('rosterReadyAfterReconnection');
            } else {
                _converse.registerIntervalHandler();
                _converse.initRoster();
            }
            // First set up chat boxes, before populating the roster, so that
            // the controlbox is properly set up and ready for the rosterview.
            _converse.chatboxes.onConnected();
            _converse.populateRoster();
            _converse.registerPresenceHandler();
            _converse.giveFeedback(__('Contacts'));
            if (reconnecting) {
                _converse.xmppstatus.sendPresence();
            } else {
                init_deferred.resolve();
                _converse.emit('initialized');
            }
        };

        this.setUserJid = function () {
            _converse.jid = _converse.connection.jid;
            _converse.bare_jid = Strophe.getBareJidFromJid(_converse.connection.jid);
            _converse.resource = Strophe.getResourceFromJid(_converse.connection.jid);
            _converse.domain = Strophe.getDomainFromJid(_converse.connection.jid);
        };

        this.onConnected = function (reconnecting) {
            /* Called as soon as a new connection has been established, either
             * by logging in or by attaching to an existing BOSH session.
             */
            // Solves problem of returned PubSub BOSH response not received
            // by browser.
            _converse.connection.flush();

            _converse.setUserJid();
            _converse.enableCarbons();

            // If there's no xmppstatus obj, then we were never connected to
            // begin with, so we set reconnecting to false.
            reconnecting = _.isUndefined(_converse.xmppstatus) ? false : reconnecting;

            if (reconnecting) {
                _converse.onStatusInitialized(true);
                _converse.emit('reconnected');
            } else {
                // There might be some open chat boxes. We don't
                // know whether these boxes are of the same account or not, so we
                // close them now.
                _converse.chatboxviews.closeAllChatBoxes();
                _converse.features = new _converse.Features();
                _converse.initStatus().done(_.partial(_converse.onStatusInitialized, false));
                _converse.emit('connected');
            }
        };

        this.RosterContact = Backbone.Model.extend({

            initialize: function (attributes) {
                var jid = attributes.jid;
                var bare_jid = Strophe.getBareJidFromJid(jid);
                var resource = Strophe.getResourceFromJid(jid);
                attributes.jid = bare_jid;
                this.set(_.assignIn({
                    'id': bare_jid,
                    'jid': bare_jid,
                    'fullname': bare_jid,
                    'chat_status': 'offline',
                    'user_id': Strophe.getNodeFromJid(jid),
                    'resources': resource ? [resource] : [],
                    'groups': [],
                    'image_type': DEFAULT_IMAGE_TYPE,
                    'image': DEFAULT_IMAGE,
                    'status': ''
                }, attributes));

                this.on('destroy', function () { this.removeFromRoster(); }.bind(this));
                this.on('change:chat_status', function (item) {
                    _converse.emit('contactStatusChanged', item.attributes);
                });
            },

            subscribe: function (message) {
                /* Send a presence subscription request to this roster contact
                 *
                 * Parameters:
                 *    (String) message - An optional message to explain the
                 *      reason for the subscription request.
                 */
                this.save('ask', "subscribe"); // ask === 'subscribe' Means we have ask to subscribe to them.
                var pres = $pres({to: this.get('jid'), type: "subscribe"});
                if (message && message !== "") {
                    pres.c("status").t(message).up();
                }
                var nick = _converse.xmppstatus.get('fullname');
                if (nick && nick !== "") {
                    pres.c('nick', {'xmlns': Strophe.NS.NICK}).t(nick).up();
                }
                _converse.connection.send(pres);
                return this;
            },

            ackSubscribe: function () {
                /* Upon receiving the presence stanza of type "subscribed",
                 * the user SHOULD acknowledge receipt of that subscription
                 * state notification by sending a presence stanza of type
                 * "subscribe" to the contact
                 */
                _converse.connection.send($pres({
                    'type': 'subscribe',
                    'to': this.get('jid')
                }));
            },

            ackUnsubscribe: function () {
                /* Upon receiving the presence stanza of type "unsubscribed",
                 * the user SHOULD acknowledge receipt of that subscription state
                 * notification by sending a presence stanza of type "unsubscribe"
                 * this step lets the user's server know that it MUST no longer
                 * send notification of the subscription state change to the user.
                 *  Parameters:
                 *    (String) jid - The Jabber ID of the user who is unsubscribing
                 */
                _converse.connection.send($pres({'type': 'unsubscribe', 'to': this.get('jid')}));
                this.destroy(); // Will cause removeFromRoster to be called.
            },

            unauthorize: function (message) {
                /* Unauthorize this contact's presence subscription
                 * Parameters:
                 *   (String) message - Optional message to send to the person being unauthorized
                 */
                _converse.rejectPresenceSubscription(this.get('jid'), message);
                return this;
            },

            authorize: function (message) {
                /* Authorize presence subscription
                 * Parameters:
                 *   (String) message - Optional message to send to the person being authorized
                 */
                var pres = $pres({to: this.get('jid'), type: "subscribed"});
                if (message && message !== "") {
                    pres.c("status").t(message);
                }
                _converse.connection.send(pres);
                return this;
            },

            removeResource: function (resource) {
                var resources = this.get('resources'), idx;
                if (resource) {
                    idx = _.indexOf(resources, resource);
                    if (idx !== -1) {
                        resources.splice(idx, 1);
                        this.save({'resources': resources});
                    }
                }
                else {
                    // if there is no resource (resource is null), it probably
                    // means that the user is now completely offline. To make sure
                    // that there isn't any "ghost" resources left, we empty the array
                    this.save({'resources': []});
                    return 0;
                }
                return resources.length;
            },

            removeFromRoster: function (callback) {
                /* Instruct the XMPP server to remove this contact from our roster
                 * Parameters:
                 *   (Function) callback
                 */
                var iq = $iq({type: 'set'})
                    .c('query', {xmlns: Strophe.NS.ROSTER})
                    .c('item', {jid: this.get('jid'), subscription: "remove"});
                _converse.connection.sendIQ(iq, callback, callback);
                return this;
            }
        });


        this.RosterContacts = Backbone.Collection.extend({
            model: _converse.RosterContact,

            comparator: function (contact1, contact2) {
                var name1, name2;
                var status1 = contact1.get('chat_status') || 'offline';
                var status2 = contact2.get('chat_status') || 'offline';
                if (_converse.STATUS_WEIGHTS[status1] === _converse.STATUS_WEIGHTS[status2]) {
                    name1 = contact1.get('fullname').toLowerCase();
                    name2 = contact2.get('fullname').toLowerCase();
                    return name1 < name2 ? -1 : (name1 > name2? 1 : 0);
                } else  {
                    return _converse.STATUS_WEIGHTS[status1] < _converse.STATUS_WEIGHTS[status2] ? -1 : 1;
                }
            },

            fetchRosterContacts: function () {
                /* Fetches the roster contacts, first by trying the
                 * sessionStorage cache, and if that's empty, then by querying
                 * the XMPP server.
                 *
                 * Returns a promise which resolves once the contacts have been
                 * fetched.
                 */
                var deferred = new $.Deferred();
                this.fetch({
                    add: true,
                    success: function (collection) {
                        if (collection.length === 0) {
                            /* We don't have any roster contacts stored in sessionStorage,
                             * so lets fetch the roster from the XMPP server. We pass in
                             * 'sendPresence' as callback method, because after initially
                             * fetching the roster we are ready to receive presence
                             * updates from our contacts.
                             */
                            _converse.send_initial_presence = true;
                            _converse.roster.fetchFromServer(deferred.resolve);
                        } else {
                            _converse.emit('cachedRoster', collection);
                            deferred.resolve();
                        }
                    }
                });
                return deferred.promise();
            },

            subscribeToSuggestedItems: function (msg) {
                _.each(msg.querySelectorAll('item'), function (item) {
                    if (item.getAttribute('action') === 'add') {
                        _converse.roster.addAndSubscribe(
                            item.getAttribute('jid'),
                            null,
                            _converse.xmppstatus.get('fullname')
                        );
                    }
                });
                return true;
            },

            isSelf: function (jid) {
                return (Strophe.getBareJidFromJid(jid) === Strophe.getBareJidFromJid(_converse.connection.jid));
            },

            addAndSubscribe: function (jid, name, groups, message, attributes) {
                /* Add a roster contact and then once we have confirmation from
                 * the XMPP server we subscribe to that contact's presence updates.
                 *  Parameters:
                 *    (String) jid - The Jabber ID of the user being added and subscribed to.
                 *    (String) name - The name of that user
                 *    (Array of Strings) groups - Any roster groups the user might belong to
                 *    (String) message - An optional message to explain the
                 *      reason for the subscription request.
                 *    (Object) attributes - Any additional attributes to be stored on the user's model.
                 */
                this.addContact(jid, name, groups, attributes).done(function (contact) {
                    if (contact instanceof _converse.RosterContact) {
                        contact.subscribe(message);
                    }
                });
            },

            sendContactAddIQ: function (jid, name, groups, callback, errback) {
                /*  Send an IQ stanza to the XMPP server to add a new roster contact.
                 *
                 *  Parameters:
                 *    (String) jid - The Jabber ID of the user being added
                 *    (String) name - The name of that user
                 *    (Array of Strings) groups - Any roster groups the user might belong to
                 *    (Function) callback - A function to call once the IQ is returned
                 *    (Function) errback - A function to call if an error occured
                 */
                name = _.isEmpty(name)? jid: name;
                var iq = $iq({type: 'set'})
                    .c('query', {xmlns: Strophe.NS.ROSTER})
                    .c('item', { jid: jid, name: name });
                _.each(groups, function (group) { iq.c('group').t(group).up(); });
                _converse.connection.sendIQ(iq, callback, errback);
            },

            addContact: function (jid, name, groups, attributes) {
                /* Adds a RosterContact instance to _converse.roster and
                 * registers the contact on the XMPP server.
                 * Returns a promise which is resolved once the XMPP server has
                 * responded.
                 *
                 *  Parameters:
                 *    (String) jid - The Jabber ID of the user being added and subscribed to.
                 *    (String) name - The name of that user
                 *    (Array of Strings) groups - Any roster groups the user might belong to
                 *    (Object) attributes - Any additional attributes to be stored on the user's model.
                 */
                var deferred = new $.Deferred();
                groups = groups || [];
                name = _.isEmpty(name)? jid: name;
                this.sendContactAddIQ(jid, name, groups,
                    function () {
                        var contact = this.create(_.assignIn({
                            ask: undefined,
                            fullname: name,
                            groups: groups,
                            jid: jid,
                            requesting: false,
                            subscription: 'none'
                        }, attributes), {sort: false});
                        deferred.resolve(contact);
                    }.bind(this),
                    function (err) {
                        alert(__("Sorry, there was an error while trying to add "+name+" as a contact."));
                        _converse.log(err);
                        deferred.resolve(err);
                    }
                );
                return deferred.promise();
            },

            addResource: function (bare_jid, resource) {
                var item = this.get(bare_jid),
                    resources;
                if (item) {
                    resources = item.get('resources');
                    if (resources) {
                        if (!_.includes(resources, resource)) {
                            resources.push(resource);
                            item.set({'resources': resources});
                        }
                    } else  {
                        item.set({'resources': [resource]});
                    }
                }
            },

            subscribeBack: function (bare_jid) {
                var contact = this.get(bare_jid);
                if (contact instanceof _converse.RosterContact) {
                    contact.authorize().subscribe();
                } else {
                    // Can happen when a subscription is retried or roster was deleted
                    this.addContact(bare_jid, '', [], { 'subscription': 'from' }).done(function (contact) {
                        if (contact instanceof _converse.RosterContact) {
                            contact.authorize().subscribe();
                        }
                    });
                }
            },

            getNumOnlineContacts: function () {
                var count = 0,
                    ignored = ['offline', 'unavailable'],
                    models = this.models,
                    models_length = models.length,
                    i;
                if (_converse.show_only_online_users) {
                    ignored = _.union(ignored, ['dnd', 'xa', 'away']);
                }
                for (i=0; i<models_length; i++) {
                    if (!_.includes(ignored, models[i].get('chat_status'))) {
                        count++;
                    }
                }
                return count;
            },

            onRosterPush: function (iq) {
                /* Handle roster updates from the XMPP server.
                 * See: https://xmpp.org/rfcs/rfc6121.html#roster-syntax-actions-push
                 *
                 * Parameters:
                 *    (XMLElement) IQ - The IQ stanza received from the XMPP server.
                 */
                var id = iq.getAttribute('id');
                var from = iq.getAttribute('from');
                if (from && from !== "" && Strophe.getBareJidFromJid(from) !== _converse.bare_jid) {
                    // Receiving client MUST ignore stanza unless it has no from or from = user's bare JID.
                    // XXX: Some naughty servers apparently send from a full
                    // JID so we need to explicitly compare bare jids here.
                    // https://github.com/jcbrand/converse.js/issues/493
                    _converse.connection.send(
                        $iq({type: 'error', id: id, from: _converse.connection.jid})
                            .c('error', {'type': 'cancel'})
                            .c('service-unavailable', {'xmlns': Strophe.NS.ROSTER })
                    );
                    return true;
                }
                _converse.connection.send($iq({type: 'result', id: id, from: _converse.connection.jid}));
                // var items = iq.querySelectorAll('query[xmlns="'+Strophe.NS.ROSTER+'"] item');
                var items = sizzle('query[xmlns="'+Strophe.NS.ROSTER+'"] item', iq);
                _.each(items, this.updateContact.bind(this));
                _converse.emit('rosterPush', iq);
                return true;
            },

            fetchFromServer: function (callback) {
                /* Get the roster from the XMPP server */
                var iq = $iq({type: 'get', 'id': _converse.connection.getUniqueId('roster')})
                        .c('query', {xmlns: Strophe.NS.ROSTER});
                return _converse.connection.sendIQ(iq, function () {
                        this.onReceivedFromServer.apply(this, arguments);
                        callback.apply(this, arguments);
                    }.bind(this));
            },

            onReceivedFromServer: function (iq) {
                /* An IQ stanza containing the roster has been received from
                 * the XMPP server.
                 */
                // var items = iq.querySelectorAll('query[xmlns="'+Strophe.NS.ROSTER+'"] item');
                var items = sizzle('query[xmlns="'+Strophe.NS.ROSTER+'"] item', iq);
                _.each(items, this.updateContact.bind(this));
                _converse.emit('roster', iq);
            },

            updateContact: function (item) {
                /* Update or create RosterContact models based on items
                 * received in the IQ from the server.
                 */
                var jid = item.getAttribute('jid');
                if (this.isSelf(jid)) { return; }
                var groups = _.map(item.getElementsByTagName('group'), Strophe.getText),
                    contact = this.get(jid),
                    ask = item.getAttribute("ask"),
                    subscription = item.getAttribute("subscription");
                if (!contact) {
                    if ((subscription === "none" && ask === null) || (subscription === "remove")) {
                        return; // We're lazy when adding contacts.
                    }
                    this.create({
                        ask: ask,
                        fullname: item.getAttribute("name") || jid,
                        groups: groups,
                        jid: jid,
                        subscription: subscription
                    }, {sort: false});
                } else {
                    if (subscription === "remove") {
                        return contact.destroy(); // will trigger removeFromRoster
                    }
                    // We only find out about requesting contacts via the
                    // presence handler, so if we receive a contact
                    // here, we know they aren't requesting anymore.
                    // see docs/DEVELOPER.rst
                    contact.save({
                        subscription: subscription,
                        ask: ask,
                        requesting: null,
                        groups: groups
                    });
                }
            },

            createRequestingContact: function (presence) {
                /* Creates a Requesting Contact.
                 *
                 * Note: this method gets completely overridden by converse-vcard.js
                 */
                var bare_jid = Strophe.getBareJidFromJid(presence.getAttribute('from'));
                var nick_el = presence.querySelector('nick[xmlns="'+Strophe.NS.NICK+'"]');
                var user_data = {
                    jid: bare_jid,
                    subscription: 'none',
                    ask: null,
                    requesting: true,
                    fullname: nick_el && nick_el.textContent || bare_jid,
                };
                this.create(user_data);
                _converse.emit('contactRequest', user_data);
            },

            handleIncomingSubscription: function (presence) {
                var jid = presence.getAttribute('from');
                var bare_jid = Strophe.getBareJidFromJid(jid);
                var contact = this.get(bare_jid);
                if (!_converse.allow_contact_requests) {
                    _converse.rejectPresenceSubscription(
                        jid,
                        __("This client does not allow presence subscriptions")
                    );
                }
                if (_converse.auto_subscribe) {
                    if ((!contact) || (contact.get('subscription') !== 'to')) {
                        this.subscribeBack(bare_jid);
                    } else {
                        contact.authorize();
                    }
                } else {
                    if (contact) {
                        if (contact.get('subscription') !== 'none')  {
                            contact.authorize();
                        } else if (contact.get('ask') === "subscribe") {
                            contact.authorize();
                        }
                    } else if (!contact) {
                        this.createRequestingContact(presence);
                    }
                }
            },

            presenceHandler: function (presence) {
                var presence_type = presence.getAttribute('type');
                if (presence_type === 'error') { return true; }
                var jid = presence.getAttribute('from'),
                    bare_jid = Strophe.getBareJidFromJid(jid),
                    resource = Strophe.getResourceFromJid(jid),
                    chat_status = _.propertyOf(presence.querySelector('show'))('textContent') || 'online',
                    status_message = _.propertyOf(presence.querySelector('status'))('textContent'),
                    contact = this.get(bare_jid);

                if (this.isSelf(bare_jid)) {
                    if ((_converse.connection.jid !== jid) &&
                        (presence_type !== 'unavailable') &&
                        (_converse.synchronize_availability === true ||
                         _converse.synchronize_availability === resource)) {
                        // Another resource has changed its status and
                        // synchronize_availability option set to update,
                        // we'll update ours as well.
                        _converse.xmppstatus.save({'status': chat_status});
                        if (status_message) {
                            _converse.xmppstatus.save({'status_message': status_message});
                        }
                    }
                    return;
                } else if (sizzle('query[xmlns="'+Strophe.NS.MUC+'"]', presence).length) {
                    return; // Ignore MUC
                }
                if (contact && (status_message !== contact.get('status'))) {
                    contact.save({'status': status_message});
                }
                if (presence_type === 'subscribed' && contact) {
                    contact.ackSubscribe();
                } else if (presence_type === 'unsubscribed' && contact) {
                    contact.ackUnsubscribe();
                } else if (presence_type === 'unsubscribe') {
                    return;
                } else if (presence_type === 'subscribe') {
                    this.handleIncomingSubscription(presence);
                } else if (presence_type === 'unavailable' && contact) {
                    // Only set the user to offline if there aren't any
                    // other resources still available.
                    if (contact.removeResource(resource) === 0) {
                        contact.save({'chat_status': "offline"});
                    }
                } else if (contact) { // presence_type is undefined
                    this.addResource(bare_jid, resource);
                    contact.save({'chat_status': chat_status});
                }
            }
        });


        this.RosterGroup = Backbone.Model.extend({
            initialize: function (attributes) {
                this.set(_.assignIn({
                    description: DESC_GROUP_TOGGLE,
                    state: _converse.OPENED
                }, attributes));
                // Collection of contacts belonging to this group.
                this.contacts = new _converse.RosterContacts();
            }
        });


        this.RosterGroups = Backbone.Collection.extend({
            model: _converse.RosterGroup,

            fetchRosterGroups: function () {
                /* Fetches all the roster groups from sessionStorage.
                 *
                 * Returns a promise which resolves once the groups have been
                 * returned.
                 */
                var deferred = new $.Deferred();
                this.fetch({
                    silent: true, // We need to first have all groups before
                                  // we can start positioning them, so we set
                                  // 'silent' to true.
                    success: deferred.resolve
                });
                return deferred.promise();
            }
        });


        this.Message = Backbone.Model.extend({
            defaults: function(){
                return {
                    msgid: _converse.connection.getUniqueId()
                };
            }
        });


        this.Messages = Backbone.Collection.extend({
            model: _converse.Message,
            comparator: 'time'
        });


        this.ChatBox = Backbone.Model.extend({

            initialize: function () {
                this.messages = new _converse.Messages();
                this.messages.browserStorage = new Backbone.BrowserStorage[_converse.message_storage](
                    b64_sha1('converse.messages'+this.get('jid')+_converse.bare_jid));
                this.save({
                    // The chat_state will be set to ACTIVE once the chat box is opened
                    // and we listen for change:chat_state, so shouldn't set it to ACTIVE here.
                    'box_id' : b64_sha1(this.get('jid')),
                    'chat_state': undefined,
                    'num_unread': this.get('num_unread') || 0,
                    'time_opened': this.get('time_opened') || moment().valueOf(),
                    'url': '',
                    'user_id' : Strophe.getNodeFromJid(this.get('jid'))
                });
            },

            getMessageAttributes: function (message, delay, original_stanza) {
                delay = delay || message.querySelector('delay');
                var type = message.getAttribute('type'),
                    body, stamp, time, sender, from;

                if (type === 'error') {
                    body = _.propertyOf(message.querySelector('error text'))('textContent');
                } else {
                    body = _.propertyOf(message.querySelector('body'))('textContent');
                }
                var delayed = !_.isNull(delay),
                    fullname = this.get('fullname'),
                    is_groupchat = type === 'groupchat',
                    chat_state = message.getElementsByTagName(_converse.COMPOSING).length && _converse.COMPOSING ||
                        message.getElementsByTagName(_converse.PAUSED).length && _converse.PAUSED ||
                        message.getElementsByTagName(_converse.INACTIVE).length && _converse.INACTIVE ||
                        message.getElementsByTagName(_converse.ACTIVE).length && _converse.ACTIVE ||
                        message.getElementsByTagName(_converse.GONE).length && _converse.GONE;

                if (is_groupchat) {
                    from = Strophe.unescapeNode(Strophe.getResourceFromJid(message.getAttribute('from')));
                } else {
                    from = Strophe.getBareJidFromJid(message.getAttribute('from'));
                }
                if (_.isEmpty(fullname)) {
                    fullname = from;
                }
                if (delayed) {
                    stamp = delay.getAttribute('stamp');
                    time = stamp;
                } else {
                    time = moment().format();
                }
                if ((is_groupchat && from === this.get('nick')) || (!is_groupchat && from === _converse.bare_jid)) {
                    sender = 'me';
                } else {
                    sender = 'them';
                }
                return {
                    'type': type,
                    'chat_state': chat_state,
                    'delayed': delayed,
                    'fullname': fullname,
                    'message': body || undefined,
                    'msgid': message.getAttribute('id'),
                    'sender': sender,
                    'time': time
                };
            },

            createMessage: function (message, delay, original_stanza) {
                return this.messages.create(this.getMessageAttributes.apply(this, arguments));
            }
        });

        this.ChatBoxes = Backbone.Collection.extend({
            model: _converse.ChatBox,
            comparator: 'time_opened',

            registerMessageHandler: function () {
                _converse.connection.addHandler(this.onMessage.bind(this), null, 'message', 'chat');
                _converse.connection.addHandler(this.onErrorMessage.bind(this), null, 'message', 'error');
            },

            chatBoxMayBeShown: function (chatbox) {
                return true;
            },

            onChatBoxesFetched: function (collection) {
                /* Show chat boxes upon receiving them from sessionStorage
                 *
                 * This method gets overridden entirely in src/converse-controlbox.js
                 * if the controlbox plugin is active.
                 */
                var that = this;
                collection.each(function (chatbox) {
                    if (that.chatBoxMayBeShown(chatbox)) {
                        chatbox.trigger('show');
                    }
                });
                _converse.emit('chatBoxesFetched');
            },

            onConnected: function () {
                this.browserStorage = new Backbone.BrowserStorage[_converse.storage](
                    b64_sha1('converse.chatboxes-'+_converse.bare_jid));
                this.registerMessageHandler();
                this.fetch({
                    add: true,
                    success: this.onChatBoxesFetched.bind(this)
                });
            },

            onErrorMessage: function (message) {
                /* Handler method for all incoming error message stanzas
                 */
                // TODO: we can likely just reuse "onMessage" below
                var from_jid =  Strophe.getBareJidFromJid(message.getAttribute('from'));
                if (from_jid === _converse.bare_jid) {
                    return true;
                }
                // Get chat box, but only create a new one when the message has a body.
                var chatbox = this.getChatBox(from_jid);
                if (!chatbox) {
                    return true;
                }
                chatbox.createMessage(message, null, message);
                return true;
            },

            onMessage: function (message) {
                /* Handler method for all incoming single-user chat "message"
                 * stanzas.
                 */
                var original_stanza = message,
                    contact_jid, forwarded, delay, from_bare_jid,
                    from_resource, is_me, msgid,
                    chatbox, resource,
                    from_jid = message.getAttribute('from'),
                    to_jid = message.getAttribute('to'),
                    to_resource = Strophe.getResourceFromJid(to_jid);

                if (_converse.filter_by_resource && (to_resource && to_resource !== _converse.resource)) {
                    _converse.log(
                        'onMessage: Ignoring incoming message intended for a different resource: '+to_jid,
                        'info'
                    );
                    return true;
                } else if (utils.isHeadlineMessage(message)) {
                    // XXX: Ideally we wouldn't have to check for headline
                    // messages, but Prosody sends headline messages with the
                    // wrong type ('chat'), so we need to filter them out here.
                    _converse.log(
                        "onMessage: Ignoring incoming headline message sent with type 'chat' from JID: "+from_jid,
                        'info'
                    );
                    return true;
                }
                forwarded = message.querySelector('forwarded');
                if (!_.isNull(forwarded)) {
                    var forwarded_message = forwarded.querySelector('message');
                    var forwarded_from = forwarded_message.getAttribute('from');
                    if (Strophe.getBareJidFromJid(forwarded_from) !== from_jid) {
                        // Prevent message forging via carbons
                        //
                        // https://xmpp.org/extensions/xep-0280.html#security
                        return true;
                    }
                    message = forwarded_message;
                    delay = forwarded.querySelector('delay');
                    from_jid = message.getAttribute('from');
                    to_jid = message.getAttribute('to');
                }
                from_bare_jid = Strophe.getBareJidFromJid(from_jid);
                from_resource = Strophe.getResourceFromJid(from_jid);
                is_me = from_bare_jid === _converse.bare_jid;
                msgid = message.getAttribute('id');
                if (is_me) {
                    // I am the sender, so this must be a forwarded message...
                    contact_jid = Strophe.getBareJidFromJid(to_jid);
                    resource = Strophe.getResourceFromJid(to_jid);
                } else {
                    contact_jid = from_bare_jid;
                    resource = from_resource;
                }
                _converse.emit('message', message);
                // Get chat box, but only create a new one when the message has a body.
                chatbox = this.getChatBox(contact_jid, !_.isNull(message.querySelector('body')));
                if (!chatbox) {
                    return true;
                }
                if (msgid && chatbox.messages.findWhere({msgid: msgid})) {
                    return true; // We already have this message stored.
                }
                chatbox.createMessage(message, delay, original_stanza);
                return true;
            },

            getChatBox: function (jid, create, attrs) {
                /* Returns a chat box or optionally return a newly
                 * created one if one doesn't exist.
                 *
                 * Parameters:
                 *    (String) jid - The JID of the user whose chat box we want
                 *    (Boolean) create - Should a new chat box be created if none exists?
                 *    (Object) attrs - Optional chat box atributes.
                 */
                jid = jid.toLowerCase();
                var bare_jid = Strophe.getBareJidFromJid(jid);
                var chatbox = this.get(bare_jid);
                if (!chatbox && create) {
                    var roster_info = {};
                    var roster_item = _converse.roster.get(bare_jid);
                    if (! _.isUndefined(roster_item)) {
                        roster_info = {
                            'fullname': _.isEmpty(roster_item.get('fullname'))? jid: roster_item.get('fullname'),
                            'image_type': roster_item.get('image_type'),
                            'image': roster_item.get('image'),
                            'url': roster_item.get('url'),
                        };
                    } else if (!_converse.allow_non_roster_messaging) {
                        _converse.log('Could not get roster item for JID '+bare_jid+
                                    ' and allow_non_roster_messaging is set to false', 'error');
                        return;
                    }
                    chatbox = this.create(_.assignIn({
                        'id': bare_jid,
                        'jid': bare_jid,
                        'fullname': jid,
                        'image_type': DEFAULT_IMAGE_TYPE,
                        'image': DEFAULT_IMAGE,
                        'url': '',
                    }, roster_info, attrs || {}));
                }
                return chatbox;
            }
        });

        this.ChatBoxViews = Backbone.Overview.extend({

            initialize: function () {
                this.model.on("add", this.onChatBoxAdded, this);
                this.model.on("destroy", this.removeChat, this);
            },

            _ensureElement: function () {
                /* Override method from backbone.js
                 * If the #conversejs element doesn't exist, create it.
                 */
                if (!this.el) {
                    var $el = $('#conversejs');
                    if (!$el.length) {
                        $el = $('<div id="conversejs">');
                        $('body').append($el);
                    }
                    $el.html('');
                    this.setElement($el, false);
                } else {
                    this.setElement(_.result(this, 'el'), false);
                }
            },

            onChatBoxAdded: function (item) {
                // Views aren't created here, since the core code doesn't
                // contain any views. Instead, they're created in overrides in
                // plugins, such as in converse-chatview.js and converse-muc.js
                return this.get(item.get('id'));
            },

            removeChat: function (item) {
                this.remove(item.get('id'));
            },

            closeAllChatBoxes: function () {
                /* This method gets overridden in src/converse-controlbox.js if
                 * the controlbox plugin is active.
                 */
                this.each(function (view) { view.close(); });
                return this;
            },

            chatBoxMayBeShown: function (chatbox) {
                return this.model.chatBoxMayBeShown(chatbox);
            },

            getChatBox: function (attrs, create) {
                var chatbox  = this.model.get(attrs.jid);
                if (!chatbox && create) {
                    chatbox = this.model.create(attrs, {
                        'error': function (model, response) {
                            _converse.log(response.responseText);
                        }
                    });
                }
                return chatbox;
            },

            showChat: function (attrs) {
                /* Find the chat box and show it (if it may be shown).
                 * If it doesn't exist, create it.
                 */
                var chatbox = this.getChatBox(attrs, true);
                if (this.chatBoxMayBeShown(chatbox)) {
                    chatbox.trigger('show', true);
                }
                return chatbox;
            }
        });


        this.XMPPStatus = Backbone.Model.extend({
            initialize: function () {
                this.set({
                    'status' : this.getStatus()
                });
                this.on('change', function (item) {
                    if (_.has(item.changed, 'status')) {
                        _converse.emit('statusChanged', this.get('status'));
                    }
                    if (_.has(item.changed, 'status_message')) {
                        _converse.emit('statusMessageChanged', this.get('status_message'));
                    }
                }.bind(this));
            },

            constructPresence: function (type, status_message) {
                var presence;
                type = _.isString(type) ? type : (this.get('status') || _converse.default_state);
                status_message = _.isString(status_message) ? status_message : undefined;
                // Most of these presence types are actually not explicitly sent,
                // but I add all of them here for reference and future proofing.
                if ((type === 'unavailable') ||
                        (type === 'probe') ||
                        (type === 'error') ||
                        (type === 'unsubscribe') ||
                        (type === 'unsubscribed') ||
                        (type === 'subscribe') ||
                        (type === 'subscribed')) {
                    presence = $pres({'type': type});
                } else if (type === 'offline') {
                    presence = $pres({'type': 'unavailable'});
                } else if (type === 'online') {
                    presence = $pres();
                } else {
                    presence = $pres().c('show').t(type).up();
                }
                if (status_message) {
                    presence.c('status').t(status_message);
                }
                return presence;
            },

            sendPresence: function (type, status_message) {
                _converse.connection.send(this.constructPresence(type, status_message));
            },

            setStatus: function (value) {
                this.sendPresence(value);
                this.save({'status': value});
            },

            getStatus: function () {
                return this.get('status') || _converse.default_state;
            },

            setStatusMessage: function (status_message) {
                this.sendPresence(this.getStatus(), status_message);
                var prev_status = this.get('status_message');
                this.save({'status_message': status_message});
                if (this.xhr_custom_status) {
                    $.ajax({
                        url:  this.xhr_custom_status_url,
                        type: 'POST',
                        data: {'msg': status_message}
                    });
                }
                if (prev_status === status_message) {
                    this.trigger("update-status-ui", this);
                }
            }
        });

        this.Session = Backbone.Model; // General session settings to be saved to sessionStorage.
        this.Feature = Backbone.Model;
        this.Features = Backbone.Collection.extend({
            /* Service Discovery
             * -----------------
             * This collection stores Feature Models, representing features
             * provided by available XMPP entities (e.g. servers)
             * See XEP-0030 for more details: http://xmpp.org/extensions/xep-0030.html
             * All features are shown here: http://xmpp.org/registrar/disco-features.html
             */
            model: _converse.Feature,
            initialize: function () {
                this.addClientIdentities().addClientFeatures();
                this.browserStorage = new Backbone.BrowserStorage[_converse.storage](
                    b64_sha1('converse.features'+_converse.bare_jid)
                );
                this.on('add', this.onFeatureAdded, this);
                if (this.browserStorage.records.length === 0) {
                    // browserStorage is empty, so we've likely never queried this
                    // domain for features yet
                    _converse.connection.disco.info(_converse.domain, null, this.onInfo.bind(this));
                    _converse.connection.disco.items(_converse.domain, null, this.onItems.bind(this));
                } else {
                    this.fetch({add:true});
                }
            },

            onFeatureAdded: function (feature) {
                _converse.emit('serviceDiscovered', feature);
            },

            addClientIdentities: function () {
                /* See http://xmpp.org/registrar/disco-categories.html
                 */
                 _converse.connection.disco.addIdentity('client', 'web', 'Converse.js');
                 return this;
            },

            addClientFeatures: function () {
                /* The strophe.disco.js plugin keeps a list of features which
                 * it will advertise to any #info queries made to it.
                 *
                 * See: http://xmpp.org/extensions/xep-0030.html#info
                 */
                _converse.connection.disco.addFeature(Strophe.NS.BOSH);
                _converse.connection.disco.addFeature(Strophe.NS.CHATSTATES);
                _converse.connection.disco.addFeature(Strophe.NS.DISCO_INFO);
                _converse.connection.disco.addFeature(Strophe.NS.ROSTERX); // Limited support
                if (_converse.message_carbons) {
                    _converse.connection.disco.addFeature(Strophe.NS.CARBONS);
                }
                return this;
            },

            onItems: function (stanza) {
                var that = this;
                _.each(stanza.querySelectorAll('query item'), function (item) {
                    _converse.connection.disco.info(
                        item.getAttribute('jid'),
                        null,
                        that.onInfo.bind(that));
                });
            },

            onInfo: function (stanza) {
                var $stanza = $(stanza);
                if (($stanza.find('identity[category=server][type=im]').length === 0) &&
                    ($stanza.find('identity[category=conference][type=text]').length === 0)) {
                    // This isn't an IM server component
                    return;
                }
                $stanza.find('feature').each(function (idx, feature) {
                    var namespace = feature.getAttribute('var');
                    this[namespace] = true;
                    this.create({
                        'var': namespace,
                        'from': stanza.getAttribute('from')
                    });
                }.bind(this));
            }
        });

        this.setUpXMLLogging = function () {
            Strophe.log = function (level, msg) {
                _converse.log(msg, level);
            };
            if (this.debug) {
                this.connection.xmlInput = function (body) { _converse.log(body.outerHTML); };
                this.connection.xmlOutput = function (body) { _converse.log(body.outerHTML); };
            }
        };

        this.fetchLoginCredentials = function () {
            var deferred = new $.Deferred();
            $.ajax({
                url:  _converse.credentials_url,
                type: 'GET',
                dataType: "json",
                success: function (response) {
                    deferred.resolve({
                        'jid': response.jid,
                        'password': response.password
                    });
                },
                error: function (response) {
                    delete _converse.connection;
                    _converse.emit('noResumeableSession');
                    deferred.reject(response);
                }
            });
            return deferred.promise();
        };

        this.startNewBOSHSession = function () {
            var that = this;
            $.ajax({
                url:  this.prebind_url,
                type: 'GET',
                dataType: "json",
                success: function (response) {
                    that.connection.attach(
                            response.jid,
                            response.sid,
                            response.rid,
                            that.onConnectStatusChanged
                    );
                },
                error: function (response) {
                    delete that.connection;
                    that.emit('noResumeableSession');
                }
            });
        };

        this.attemptPreboundSession = function (reconnecting) {
            /* Handle session resumption or initialization when prebind is being used.
             */
            if (!reconnecting && this.keepalive) {
                if (!this.jid) {
                    throw new Error("attemptPreboundSession: when using 'keepalive' with 'prebind, "+
                                    "you must supply the JID of the current user.");
                }
                try {
                    return this.connection.restore(this.jid, this.onConnectStatusChanged);
                } catch (e) {
                    this.log("Could not restore session for jid: "+this.jid+" Error message: "+e.message);
                    this.clearSession(); // If there's a roster, we want to clear it (see #555)
                }
            }

            // No keepalive, or session resumption has failed.
            if (!reconnecting && this.jid && this.sid && this.rid) {
                return this.connection.attach(this.jid, this.sid, this.rid, this.onConnectStatusChanged);
            } else if (this.prebind_url) {
                return this.startNewBOSHSession();
            } else {
                throw new Error("attemptPreboundSession: If you use prebind and not keepalive, "+
                    "then you MUST supply JID, RID and SID values or a prebind_url.");
            }
        };

        this.autoLogin = function (credentials) {
            if (credentials) {
                // If passed in, then they come from credentials_url, so we
                // set them on the _converse object.
                this.jid = credentials.jid;
                this.password = credentials.password;
            }
            if (this.authentication === _converse.ANONYMOUS) {
                if (!this.jid) {
                    throw new Error("Config Error: when using anonymous login " +
                        "you need to provide the server's domain via the 'jid' option. " +
                        "Either when calling converse.initialize, or when calling " +
                        "_converse.api.user.login.");
                }
                this.connection.connect(this.jid.toLowerCase(), null, this.onConnectStatusChanged);
            } else if (this.authentication === _converse.LOGIN) {
                var password = _converse.connection.pass || this.password;
                if (!password) {
                    if (this.auto_login && !this.password) {
                        throw new Error("initConnection: If you use auto_login and "+
                            "authentication='login' then you also need to provide a password.");
                    }
                    _converse.setDisconnectionCause(Strophe.Status.AUTHFAIL, undefined, true);
                    _converse.disconnect();
                    return;
                }
                var resource = Strophe.getResourceFromJid(this.jid);
                if (!resource) {
                    this.jid = this.jid.toLowerCase() + _converse.generateResource();
                } else {
                    this.jid = Strophe.getBareJidFromJid(this.jid).toLowerCase()+'/'+resource;
                }
                this.connection.connect(this.jid, password, this.onConnectStatusChanged);
            }
        };

        this.attemptNonPreboundSession = function (credentials, reconnecting) {
            /* Handle session resumption or initialization when prebind is not being used.
             *
             * Two potential options exist and are handled in this method:
             *  1. keepalive
             *  2. auto_login
             */
            if (this.keepalive && !reconnecting) {
                try {
                    return this.connection.restore(this.jid, this.onConnectStatusChanged);
                } catch (e) {
                    this.log("Could not restore session. Error message: "+e.message);
                    this.clearSession(); // If there's a roster, we want to clear it (see #555)
                }
            }
            if (this.auto_login) {
                if (credentials) {
                    // When credentials are passed in, they override prebinding
                    // or credentials fetching via HTTP
                    this.autoLogin(credentials);
                } else if (this.credentials_url) {
                    this.fetchLoginCredentials().done(this.autoLogin.bind(this));
                } else if (!this.jid) {
                    throw new Error(
                        "initConnection: If you use auto_login, you also need"+
                        "to give either a jid value (and if applicable a "+
                        "password) or you need to pass in a URL from where the "+
                        "username and password can be fetched (via credentials_url)."
                    );
                } else {
                    // Probably ANONYMOUS login
                    this.autoLogin();
                }
            } else if (reconnecting) {
                this.autoLogin();
            }
        };

        this.logIn = function (credentials, reconnecting) {
            // We now try to resume or automatically set up a new session.
            // Otherwise the user will be shown a login form.
            if (this.authentication === _converse.PREBIND) {
                this.attemptPreboundSession(reconnecting);
            } else {
                this.attemptNonPreboundSession(credentials, reconnecting);
            }
        };

        this.initConnection = function () {
            if (this.connection) {
                return;
            }
            if (!this.bosh_service_url && ! this.websocket_url) {
                throw new Error("initConnection: you must supply a value for either the bosh_service_url or websocket_url or both.");
            }
            if (('WebSocket' in window || 'MozWebSocket' in window) && this.websocket_url) {
                this.connection = new Strophe.Connection(this.websocket_url, this.connection_options);
            } else if (this.bosh_service_url) {
                this.connection = new Strophe.Connection(
                    this.bosh_service_url,
                    _.assignIn(this.connection_options, {'keepalive': this.keepalive})
                );
            } else {
                throw new Error("initConnection: this browser does not support websockets and bosh_service_url wasn't specified.");
            }
        };

        this._tearDown = function () {
            /* Remove those views which are only allowed with a valid
             * connection.
             */
            this.unregisterPresenceHandler();
            if (this.roster) {
                this.roster.off().reset(); // Removes roster contacts
            }
            this.chatboxes.remove(); // Don't call off(), events won't get re-registered upon reconnect.
            if (this.features) {
                this.features.reset();
            }
            $(window).off('click mousemove keypress focus'+unloadevent, _converse.onUserActivity);
            window.clearInterval(_converse.everySecondTrigger);
            return this;
        };

        this.initChatBoxes = function () {
            this.chatboxes = new this.ChatBoxes();
            this.chatboxviews = new this.ChatBoxViews({model: this.chatboxes});
        };

        this._initialize = function () {
            this.initChatBoxes();
            this.initSession();
            this.initConnection();
            this.setUpXMLLogging();
            this.logIn();
            return this;
        };

        // Initialization
        // --------------
        // This is the end of the initialize method.
        if (settings.connection) {
            this.connection = settings.connection;
        }
        var updateSettings = function (settings) {
            /* Helper method which gets put on the plugin and allows it to
             * add more user-facing config settings to converse.js.
             */
            utils.merge(_converse.default_settings, settings);
            utils.merge(_converse, settings);
            utils.applyUserSettings(_converse, settings, _converse.user_settings);
        };

        // If initialize gets called a second time (e.g. during tests), then we
        // need to re-apply all plugins (for a new converse instance), and we
        // therefore need to clear this array that prevents plugins from being
        // initialized twice.
        // If initialize is called for the first time, then this array is empty
        // in any case.
        _converse.pluggable.initialized_plugins = [];

        var whitelist = _converse.core_plugins.concat(_converse.whitelisted_plugins);

        _converse.pluggable.initializePlugins({
            'updateSettings': updateSettings,
            '_converse': _converse
        }, whitelist, _converse.blacklisted_plugins);

        _converse.emit('pluginsInitialized');
        _converse._initialize();
        _converse.registerGlobalEventHandlers();

        if (!_.isUndefined(_converse.connection) &&
            _converse.connection.service === 'jasmine tests') {
            return _converse;
        } else {
            return init_deferred.promise();
        }
    };
    return _converse;
}));