Cable-Desktop/libtextsecure/websocket.js

/* vim: ts=4:sw=4:expandtab
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * var socket = TextSecureWebSocket(url);
 *
 * Returns an adamantium-reinforced super socket, capable of sending
 * app-level keep alives and automatically reconnecting.
 *
 */

TextSecureWebSocket = function (url) {
    'use strict';
    var keepAliveTimer;
    var reconnectSemaphore = 0;
    var reconnectTimeout = 1000;
    var socket;
    var calledClose = false;
    var socketWrapper = {
        onmessage : function() {},
        onclose   : function() {},
        onerror   : function() {},
        getStatus : function() { return socket.readyState; },
        close     : function() { calledClose = true; }
    };
    var error;

    function resetKeepAliveTimer() {
        clearTimeout(keepAliveTimer);
        if (calledClose) { return; }
        keepAliveTimer = setTimeout(function() {
            if (socket.readyState === WebSocket.OPEN) {
                socket.send(
                    new textsecure.protobuf.WebSocketMessage({
                        type: textsecure.protobuf.WebSocketMessage.Type.REQUEST,
                        request: { verb: 'GET', path: '/v1/keepalive' }
                    }).encode().toArrayBuffer()
                );
            }

            resetKeepAliveTimer();
        }, 55000);
    };

    function onclose(e) {
        if (!error && !calledClose) {
            reconnectSemaphore--;
            setTimeout(connect, reconnectTimeout);
        }
        if (e !== 1000 ) { // CLOSE_NORMAL
            console.log('websocket closed', e.code);
        }
        socketWrapper.onclose(e);
    };

    function onerror(e) {
        error = e;
        console.log('websocket error');
        socketWrapper.onerror(e);
    };

    function onmessage(response) {
        socketWrapper.onmessage(response);
        resetKeepAliveTimer();
    };

    function send(msg) {
        resetKeepAliveTimer();
        socket.send(msg);
    };

    function connect() {
        clearTimeout(keepAliveTimer);
        if (++reconnectSemaphore <= 0) { return; }

        if (socket) { socket.close(); }
        socket = new WebSocket(url);

        socket.onopen      = resetKeepAliveTimer;
        socket.onerror     = onerror
        socket.onclose     = onclose;
        socket.onmessage   = onmessage;
        socketWrapper.send = send;
    };

    connect();
    return socketWrapper;
};