owncloud/core

/**
 * ownCloud
 *
 * @author Robin Appelman
 * @copyright Copyright (c) 2012 Robin Appelman icewind1991@gmail.com
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library 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 AFFERO GENERAL PUBLIC LICENSE for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/**
 * Wrapper for server side events
 * (http://en.wikipedia.org/wiki/Server-sent_events)
 * includes a fallback for older browsers and IE
 *
 * use server side events with caution, too many open requests can hang the
 * server
 */

/* global EventSource */

/**
 * Create a new event source
 * @param {string} src
 * @param {object} [data] to be send as GET
 *
 * @constructs OC.EventSource
 */
OC.EventSource=function(src,data){
    var dataStr='';
    var name;
    var joinChar;
    this.typelessListeners=[];
    this.closed = false;
    this.listeners={};
    if(data){
        for(name in data){
            dataStr+=name+'='+encodeURIComponent(data[name])+'&';
        }
    }
    dataStr+='requesttoken='+encodeURIComponent(oc_requesttoken);
    if(!this.useFallBack && typeof EventSource !== 'undefined'){
        joinChar = '&';
        if(src.indexOf('?') === -1) {
            joinChar = '?';
        }
        this.source= new EventSource(src+joinChar+dataStr);
        this.source.onmessage=function(e){
            for(var i=0;i<this.typelessListeners.length;i++){
                this.typelessListeners[i](JSON.parse(e.data));
            }
        }.bind(this);
    }else{
        var iframeId='oc_eventsource_iframe_'+OC.EventSource.iframeCount;
        OC.EventSource.fallBackSources[OC.EventSource.iframeCount]=this;
        this.iframe=$('<iframe/>');
        this.iframe.attr('id',iframeId);
        this.iframe.hide();

        joinChar = '&';
        if(src.indexOf('?') === -1) {
            joinChar = '?';
        }
        this.iframe.attr('src',src+joinChar+'fallback=true&fallback_id='+OC.EventSource.iframeCount+'&'+dataStr);
        $('body').append(this.iframe);
        this.useFallBack=true;
        OC.EventSource.iframeCount++;
    }
    //add close listener
    this.listen('__internal__',function(data){
        if(data === 'close'){
            this.close();
        }
    }.bind(this));
};
OC.EventSource.fallBackSources=[];
OC.EventSource.iframeCount=0;//number of fallback iframes
OC.EventSource.fallBackCallBack=function(id,type,data){
    OC.EventSource.fallBackSources[id].fallBackCallBack(type,data);
};
OC.EventSource.prototype={
    typelessListeners:[],
    iframe:null,
    listeners:{},//only for fallback
    useFallBack:false,
    /**
     * Fallback callback for browsers that don't have the
     * native EventSource object.
     *
     * Calls the registered listeners.
     *
     * @private
     * @param {String} type event type
     * @param {Object} data received data
     */
    fallBackCallBack:function(type,data){
        var i;
        // ignore messages that might appear after closing
        if (this.closed) {
            return;
        }
        if(type){
            if (typeof this.listeners.done !== 'undefined') {
                for(i=0;i<this.listeners[type].length;i++){
                    this.listeners[type][i](data);
                }
            }
        }else{
            for(i=0;i<this.typelessListeners.length;i++){
                this.typelessListeners[i](data);
            }
        }
    },
    lastLength:0,//for fallback
    /**
     * Listen to a given type of events.
     *
     * @param {String} type event type
     * @param {Function} callback event callback
     */
    listen:function(type,callback){
        if(callback && callback.call){

            if(type){
                if(this.useFallBack){
                    if(!this.listeners[type]){
                        this.listeners[type]=[];
                    }
                    this.listeners[type].push(callback);
                }else{
                    this.source.addEventListener(type,function(e){
                        if (typeof e.data !== 'undefined') {
                            callback(JSON.parse(e.data));
                        } else {
                            callback('');
                        }
                    },false);
                }
            }else{
                this.typelessListeners.push(callback);
            }
        }
    },
    /**
     * Closes this event source.
     */
    close:function(){
        this.closed = true;
        if (typeof this.source !== 'undefined') {
            this.source.close();
        }
    }
};