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Watson Assistant context is not updated

I use watson assistant v1
My problem is that every time I make a call to the code in Nodejs, where I return the context, to have a coordinated conversation, the context is only updated once and I get stuck in a node of the conversation
this is my code
client.on('message', message => {
//general variables
var carpetaIndividual = <../../../>
var cuerpoMensaje = <....>
var emisorMensaje = <....>
//detect if context exists
if(fs.existsSync(carpetaIndividual+'/contexto.json')) {
var watsonContexto = require(carpetaIndividual+'/contexto.json');
var variableContexto = watsonContexto;
} else {
var variableContexto = {}
}
//conection with Watson Assistant
assistant.message(
{
input: { text: cuerpoMensaje },
workspaceId: '<>',
context: variableContexto,
})
.then(response => {
let messageWatson = response.result.output.text[0];
let contextoWatson = response.result.context;
console.log('Chatbot: ' + messageWatson);
//Save and create JSON file for context
fs.writeFile(carpetaIndividual+'/contexto.json', JSON.stringify(contextoWatson), 'utf8', function (err) {
if (err) {
console.error(err);
}
});
//Send messages to my application
client.sendMessage(emisorMensaje, messageWatson)
})
.catch(err => {
console.log(err);
});
}
client.initialize();
the context.json file is updated, but when it is read the code only reads the first update of the context.json file and not the other updates

This will be because you are using require to read the .json file. For all subsequent requires of an already-required file, the data is cached and reused.
You will need to use fs.readfile and JSON.parse
// detect if context exists
if (fs.existsSync(carpetaIndividual+'/contexto.json')) {
var watsonContexto = fs.readFileSync(carpetaIndividual+'/contexto.json');
// Converting to JSON
var variableContexto = JSON.parse(watsonContexto);
} else {
var variableContexto = {}
}
There is another subtle problem with your code, in that you are relying on
your async call to fs.writeFile completing before you read the file. This will be the case most of the time, but as you don't wait for the fs.writeFile to complete there is the chance that you may try to read the file, before it is written.

Connect JS secure websocket to C# websocket server (Fleck)

I have an API in C# (asp.net) in which i'm running this websocket server using fleck:
SocketService.start();
SocketService.server.Start(socket =>
{
socket.OnOpen = () =>
{
SocketService.Connessione(socket);
};
socket.OnClose = () =>
{
SocketService.Disconnesione(socket);
};
socket.OnMessage = message =>
{
SocketService.Messaggio(message, socket);
};
});
This is SocketService.Start():
public static void start()
{
server = new WebSocketServer($"wss://{GetLocalIPAddress()}:{"4450"}/BNS/");
}
I have tried with a simple HTML/JS page using unsecure ws and it worked fine.
Then I have tried in my main program which i need it to be run on HTTPS so when using unsecure ws chrome told me to use wss instead.
So i change my ws server to wss but then it does nothing, it gives me timeout error.
This is the JS code:
var start = function () {
var wsImpl = window.WebSocket || window.MozWebSocket;
var form = document.getElementById('sendForm');
var input = document.getElementById('sendText');
alert("Connessione...");
// create a new websocket and connect
window.ws = new wsImpl('#Percorsi.IndirizzoSocket');
alert("conn");
// when the connection is established, this method is called
ws.onopen = function () {
alert("Connessione aperta");
var openJson = {
"Id": "#Model.accountCorrente.Id",
"type": "Identificazione"
};
alert("send");
ws.send(stringify(openJson));
};
// when the connection is closed, this method is called
ws.onclose = function () {
alert("Connessione chiusa");
}
// when data is comming from the server, this metod is called
ws.onmessage = function (val) {
if (confirm("Hai ricevuto un nuovo messaggio!\nPremi ok per visualizzarlo.")) {
window.location("/Annunci/Chat/" + val);
} else { }
};
}
I can't figured out how to make it works.
Thanks in advance for your help!

It seems like you are not setting the server certificate to be used under WS over TLS (not to be confused with HTTPS which is HTTP over TLS).
If you see the example in fleck's webpage, you will realize that you have to set the Certificate:
server.Certificate = new X509Certificate2("MyCert.pfx");

NodeJS/ES6: Cannot set property of undefined

Using NodeJS/ES6 I have created a MongoDB connector class.
class DBClient {
constructor(host, port) {
this.host = host;
this.port = port
this.dbConnection = null;
}
buildConnectionString() {
return 'mongodb://' + this.host + ':' + this.port;
}
connect() {
var connectionString = this.buildConnectionString();
console.log('[MongoDB] - Connecting to instance # ' + connectionString);
var DBConnection = MongoClient.connect(connectionString, function(error, db) {
if (error) {
console.log('[MongoDB] - Error connecting to instance');
console.log(error);
}
else {
console.log('[MongoDB] - Connection Successful');
this.dbConnection = db;
}
});
}
}
Which is then being created in a different file like so
var client = new DBClient('127.0.0.1', '1337');
client.connect();
When the database is connected to, NodeJS crashes when it reaches this.dbConnection = db;, stating TypeError: Cannot set property 'dbConnection' of undefined.
I'm pretty sure it has something to do with being used in a callback, which is screwing up the scope. How can I get around this though? Wouldn't any operation from the callback scope be isolated and unable to reference this?
Also, as a side question, is this a bad code practice to initialize a null property like I'm doing in the constructor? If so, what would be a more proper way of doing it?

Indeed if you want to keep your scope use lambda instead like :
var DBConnection = MongoClient.connect(connectionString, (error, db) =>
{
...
});
if you have to keep your function because of your transpilation settings or the lib does not support lambda, save your scope in a variable like :
var self = this;
var DBConnection = MongoClient.connect(connectionString, function(error, db)
{
... self.dbConnection = db;
});

How to mock http.ServerResponse and http.IncomingMessage for express.static

I've had no trouble testing my own route handlers but in this case I want to test express's static handler. I can't for the life of me figure out why it's hanging. Clearly there's some callback I'm missing or some event I need to emit.
I tried to make the smallest example I could.
var events = require('events');
var express = require('express');
var stream = require('stream');
var util = require('util');
function MockResponse(callback) {
stream.Writable.call(this);
this.headers = {};
this.statusCode = -1;
this.body = undefined;
this.setHeader = function(key, value) {
this.headers[key] = value;
}.bind(this);
this.on('finish', function() {
console.log("finished response");
callback();
});
};
util.inherits(MockResponse, stream.Writable);
MockResponse.prototype._write = function(chunk, encoding, done) {
if (this.body === undefined) {
this.body = "";
}
this.body += chunk.toString(encoding !== 'buffer' ? encoding : undefined);
done();
};
function createRequest(req) {
var emitter = new events.EventEmitter();
req.on = emitter.on.bind(emitter);
req.once = emitter.once.bind(emitter);
req.addListener = emitter.addListener.bind(emitter);
req.emit = emitter.emit.bind(emitter);
return req;
};
describe('test', function() {
var app;
before(function() {
app = express();
app.use(express.static(__dirname));
});
it('gets test.js', function(done) {
var req = createRequest({
url: "http://foo.com/test.js",
method: 'GET',
headers: {
},
});
var res = new MockResponse(responseDone);
app(req, res);
function responseDone() {
console.log("done");
done();
}
});
});
Setup,
mkdir foo
cd foo
mkdir test
cat > test/test.js # copy and paste code above
^D
npm install express
npm install mocha
node node_modules/mocha/bin/mocha --recursive
it just times out.
What am I missing?
I also tried making the request a Readable stream. No change
var events = require('events');
var express = require('express');
var stream = require('stream');
var util = require('util');
function MockResponse(callback) {
stream.Writable.call(this);
this.headers = {};
this.statusCode = -1;
this.body = undefined;
this.setHeader = function(key, value) {
this.headers[key] = value;
}.bind(this);
this.on('finish', function() {
console.log("finished response");
callback();
});
};
util.inherits(MockResponse, stream.Writable);
MockResponse.prototype._write = function(chunk, encoding, done) {
if (this.body === undefined) {
this.body = "";
}
this.body += chunk.toString(encoding !== 'buffer' ? encoding : undefined);
done();
};
function MockMessage(req) {
stream.Readable.call(this);
var self = this;
Object.keys(req).forEach(function(key) {
self[key] = req[key];
});
}
util.inherits(MockMessage, stream.Readable);
MockMessage.prototype._read = function() {
this.push(null);
};
describe('test', function() {
var app;
before(function() {
app = express();
app.use(express.static(__dirname));
});
it('gets test.js', function(done) {
var req = new MockMessage({
url: "http://foo.com/test.js",
method: 'GET',
headers: {
},
});
var res = new MockResponse(responseDone);
app(req, res);
function responseDone() {
console.log("done");
done();
}
});
});
I've still been digging. Look inside static-server I see it creates a Readable stream by calling fs.createReadStream. It does effectively
var s = fs.createReadStream(filename);
s.pipe(res);
So trying that myself works just fine
it('test stream', function(done) {
var s = fs.createReadStream(__dirname + "/test.js");
var res = new MockResponse(responseDone);
s.pipe(res);
function responseDone() {
console.log("done");
done();
}
});
I thought maybe it's something about express waiting for the input stream to finish but that doesn't seem to be it either. If I consume the mock input stream with the response it works just fine
it('test msg->res', function(done) {
var req = new MockMessage({});
var res = new MockResponse(responseDone);
req.pipe(res);
function responseDone() {
console.log("done");
done();
}
});
Any insight what I might be missing would be helpful
Note: while suggestions for 3rd party mocking libraries are appreciated I'm still really looking to understand what I'm missing to do it myself. Even if I eventually switch to some library I still want to know why this isn't working.

I found two issues that prevent the finish callback from being executed.
serve-static uses send module which is used to create file readstream from the path and pipe it to res object. But that module uses on-finished module which checks if finished attribute is set to false in response object, otherwise it destroys the file readstream. So filestream never gets a chance to emit data event.
express initialization overwrites the response object prototype. So the default stream methods like end() method is overwritten by http response prototype:
exports.init = function(app){
return function expressInit(req, res, next){
...
res.__proto__ = app.response;
..
};
};
To prevent this, I added another middleware right before static middleware to reset it back to MockResponse prototype:
app.use(function(req, res, next){
res.__proto__ = MockResponse.prototype; //change it back to MockResponse prototype
next();
});
Here are the changes made to make it work with MockResponse:
...
function MockResponse(callback) {
...
this.finished = false; // so `on-finished` module doesn't emit finish event prematurely
//required because of 'send' module
this.getHeader = function(key) {
return this.headers[key];
}.bind(this);
...
};
...
describe('test', function() {
var app;
before(function() {
app = express();
//another middleware to reset the res object
app.use(function(req, res, next){
res.__proto__ = MockResponse.prototype;
next();
});
app.use(express.static(__dirname));
});
...
});
EDIT:
As #gman pointed out, it is possible to use direct property instead of prototype method. In that case the extra middleware to overwrite prototype isn't necessary:
function MockResponse(callback) {
...
this.finished = false; // so `on-finished` module doesn't emit finish event prematurely
//required because of 'send' module
this.getHeader = function(key) {
return this.headers[key];
}.bind(this);
...
//using direct property for _write, write, end - since all these are changed when prototype is changed
this._write = function(chunk, encoding, done) {
if (this.body === undefined) {
this.body = "";
}
this.body += chunk.toString(encoding !== 'buffer' ? encoding : undefined);
done();
};
this.write = stream.Writable.prototype.write;
this.end = stream.Writable.prototype.end;
};

It appears my answer is not complete. For some reason the app works only if the file is not found. First thing to debug is do the following in your shell (or cmd):
export DEBUG=express:router,send
then run the test, you'll get more info.
Meanwhile I am still looking into this, for now, ignore my answer below.
----------- ignore this till I verify that it does work -----------
It seems like express static does not favor the absolute path you give it (__dirname).
Try:
app.use(express.static('.'));
and it will work. Note that your current dir for the mocha runner is 'test/'
I have to admit this is quite a mistery. I tried 'fulling' it by doing:
app.use(express.static(__dirname + '/../test')
but still it didn't work. Even specifying a full path did not solve this. Strange.

how to prevent new connection on every page refresh in sockjs

So, every time I refresh the page, it seems like sockjs is creating a new connection.
I am saving every message to my mongodb on every channel.onmessage, so if I refresh my page 7 times and send a message, I would save 7 messages of the same content into my mongodb.
This is very problematic because when I retrieve those messages when I go into the chat room, to see the log, I would see bunch of duplicate messages.
I want to keep track of all connections that are 'active', and if a user tries to make another connection, I want to terminate the old one so there is only one connection listening to each message at a time.
How do I do this ?
var connections = {};
//creating the sockjs server
var chat = sockjs.createServer();
//installing handlers for sockjs server instance, with the same url as client
chat.installHandlers(server, {prefix:'/chat/private'});
var multiplexer = new multiplexServer.MultiplexServer(chat);
var configChannel = function (channelId, userId, userName){
var channel = multiplexer.registerChannel(channelId);
channel.on('connection', function (conn) {
// console.log('connection');
console.log(connections);
connections[channelId] = connections[channelId] || {};
if (connections[channelId][userId]) {
//want to close the extra connection
} else {
connections[channelId][userId] = conn;
}
// }
// if (channels[channelId][userId]) {
// conn = channels[channelId][userId];
// } else {
// channels[channelId][userId] = conn;
// }
// console.log('accessing channel! ', channels[channelId]);
conn.on('new user', function (data, message) {
console.log('new user! ', data, message);
});
// var number = connections.length;
conn.on('data', function(message) {
var messageObj = JSON.parse(message);
handler.saveMessage(messageObj.channelId, messageObj.user, messageObj.message);
console.log('received the message, ', messageObj.message);
conn.write(JSON.stringify({channelId: messageObj.channelId, user: messageObj.user, message: messageObj.message }));
});
conn.on('close', function() {
conn.write(userName + ' has disconnected');
});
});
return channel;
};

The way I resolve a problem like yours was with a Closure and Promises, I don't know if that could help you. I let you the code that help me, this is with EventBus from Vertx:
window.Events = (function NewEvents() {
var eventBusUrl = $('#eventBusUrl').val();
var eventBus = null;
return new RSVP.Promise(function(resolve, reject) {
if(!eventBus) {
eventBus = new vertx.EventBus(eventBusUrl);
eventBus.onopen = function eventBusOpened() {
console.log('Event bus online');
resolve(eventBus);
}
eventBus.onclose = function() {
eventBus = null;
};
}
});
}());
And then in other script I call it in this way:
Events.then(function(eventBus) {
console.log("registering handlers for comments");
eventBus.registerHandler(address, function(incomingMessage) {
console.log(incomingMessage);
});
});
I hope this can help you.
Regards.