dl/examples/nsess.js

DreamLab Libs

var JsonRpcMethod = require('core').jsonrpc.JsonRpcMethod,
    Event = require('core').event.Event,
    ErrorEvent = require('core').event.ErrorEvent,
    Request = require('core').http.Request,
    Response = require('core').http.Response,
    BinaryData = require('core').data.BinaryData,
    NsessManager = require('dl').nsess.NsessManager;

var QueryMethod = function () {
    JsonRpcMethod.apply(this, arguments);
};

QueryMethod.prototype = Object.create(JsonRpcMethod.prototype);

QueryMethod.prototype.execute = function (params) {
    var request = new Request(params.request),
        response = new Response({
            "headers": {
                "content-type": "text/javascript; charset=utf-8",
                "cache-control": "no-cache, must-revalidate, post-check=0, pre-check=0",
                "pargma": "no-cache"
            }
        }),
        session = new NsessManager(request, response),
        dispatched = false,
        that = this;
    
    session.addEventListener(NsessManager.Event.ERROR, function (e) {
        var body;
        
        if (!dispatched) {
            dispatched = true;
            body = new BinaryData(JSON.stringify(e.toJson()), BinaryData.Encoding.TEXT, BinaryData.CharacterEncoding.UTF8);
            response.setStatusCode(503);
            response.setBody(body);
            response.setHeader("content-length", body.length());
            this.dispatchEvent(new Event(JsonRpcMethod.Event.OK, response.toJson()));
        }
    }, this);
    
    session.get(function (err, data) {
        if (!err) {
            if (data) {
                data = JSON.parse(JSON.stringify(data));    // clone
            } else {
                data = {};
            }
            if (data.counter) {
                ++data.counter;
            } else {
                data.counter = 1;
            }
            data.time = new Date();
            try {
                session.set(data);
            } catch (e) {
                session.dispatchEvent(new ErrorEvent(NsessManager.Event.ERROR, null, -1, e.toString()));
                return;
            }

            session.addEventListener(NsessManager.Event.WRITE_OK, function (e) {
                var body;
                
                if (!dispatched) {
                    dispatched = true;
                    body = new BinaryData(JSON.stringify(data), BinaryData.Encoding.TEXT, BinaryData.CharacterEncoding.UTF8);
                    response.setStatusCode(200);
                    response.setBody(body);
                    response.setHeader("content-length", body.length());
                    this.dispatchEvent(new Event(JsonRpcMethod.Event.OK, response.toJson()));
                }
            }, that);
            
            try {
                session.write();
            } catch (e) {
                session.dispatchEvent(new ErrorEvent(NsessManager.Event.ERROR, null, -1, e.toString()));
                return;
            }
        }
    });
};

exports.QueryMethod = QueryMethod;