Alexa: Emit not working in chaining of function - node.js

I am trying to ask a question to the user and using AMAZON.yesIntent and noIntent to capture the response. In case I get response, I am calling other function which should emit something back to user. But the emit is not being called. Code below:
'use strict';
var Alexa = require("alexa-sdk");
var https = require('https');
var alexa;
exports.handler = function(event, context, callback) {
alexa = Alexa.handler(event, context);
alexa.registerHandlers(handlers);
alexa.execute();
};
var handlers = {
'LaunchRequest': function() {
alexa.emit(':ask', 'my text');
},
'oneShotIntent': function() {
var self = this;
// removed the code for simplicity
self.attributes['yes_no'] = true;
alexa.emit(':ask', 'sample yes no question');
})
},
'AMAZON.YesIntent': function () {
if (this.attributes['yes_no']) {
delete this.attributes['yes_no'];
alexa.emit('oneShotSecond');
}
},
'oneShotSecond': function() {
delete this.attributes['yes_no']; // already deleted
// removed code for simplicity
var self = this;
// removed code for simplicity
console.log(info);
if (info) {
console.log('here in if condition');
self.emit(':tell', 'sample text');
} else {
self.emit(':tell', 'sorry failed');
}
});
}
};
The first emit is working. The console.log in other function are happening. But emit is failing.
No logs in cloudwatch also. It just ends after printing the console.log data points.
Any help?

I am not sure if I understand
alexa.emit('oneShotSecond');
However I would have done it like below
oneShotSecond(this);
And then
'oneShotSecond': function(self) { // use self.emit}

Related

How to pass full request or response in Redis Bull queue

It may be a wrong way to use bull queue but here is what I want to do:
var Promise = require('bluebird');
var redis = require('redis');
var Queue = require('bull');
var redisClient = redis.createClient(6379);
var pdfQueue = new Queue('msg');
function check(resolve, reject,i) {
console.log('check called');
//Or if it is in Router then I want to send request, response in queue so that I can call them in on complete function
pdfQueue.add('msg',{'msg':'Hello', 'resolve':resolve,'reject':reject}).then(job=>{
console.log('added to the pdf')
});
}
pdfQueue.on('completed', function (job, result) {
//Here I want to call request.send('some msg');
//and resolve('complete');
resolve('final callback');
})
pdfQueue.process('msg',100,function (job,done) {
console.log('process');
done(null,'job done ')
})
function check2 () {
return new Promise(function(resolve, reject){
check(resolve,reject);
})
}
check2().then(data => {
console.log('got the value ', data)
});
In my real project I want to implement queue where I will be sending pdf to the user. Like res.download(pdf path); but this function should be in pdf.on('completed',()=>{ res.download(pdf path); }); or in resolve(pdfPath) but I am not able to find anyway to send pdf to the user using queue because I don't know how to call response or resolve in other functions by using queue jobs.
Please help me. Thanks you

RabbitMQ request, always timesout

I have a weird problem where my callback is never published and the message goes to timeout, even though the method runs in the queue. This happens in some specific queues and after it happens once, i cannot make any other requests from client which even previously worked, they all timeout. Have to restart the client and sever to make it working again.
This is the code, where its happening, and i cant seem to understand whats wrong.
Server.js file where i am creating the queues. I have several such queues, this is one of them.
var amqp = require('amqp');
var util = require('util');
var cnn = amqp.createConnection({host:'127.0.0.1'});
var getCart = require('./services/getCart');
cnn.on('ready', function() {
cnn.queue('getCart_queue', function(q){
q.subscribe(function(message, headers, deliveryInfo, m){
// util.log(util.format( deliveryInfo.routingKey, message));
// util.log("Message: "+JSON.stringify(message));
// util.log("DeliveryInfo: "+JSON.stringify(deliveryInfo));
getCart.handle_request(message, function(err,res){
cnn.publish(m.replyTo, res, {
contentType:'application/json',
contentEncoding:'utf-8',
correlationId:m.correlationId
});
});
});
});
});
Here, the handle request function is completed successfully, but the callback never goes through and its always timeout on the other end
var cart = require('../models/cart');
function handle_request(msg, callback) {
var user_id = msg.id;
cart
.find({id:user_id})
.populate('users ads')
.exec(function(err, results){
// This works, just the callback doesnt
if(!err){
console.log(results);
callback(null, results);
} else {
console.log(err);
callback(err, null);
}
});
}
exports.handle_request = handle_request;
this is how i am calling the request
var msg_payload = {"id":id};
mq_client.make_request('getCart_queue', msg_payload, function(err, results){
console.log(results); // never prints
//stuff that is never reached
});
These are my rpc files, i dont think there should be anything wrong with these, as some other queues work fine.
And this is the error shown on client
GET /getCart - - ms - -
Error: timeout 6ee0bd2a4b2ba1d8286e068b0f674d8f
at Timeout.<anonymous> (E:\Ebay_client\rpc\amqprpc.js:32:18)
at Timeout.ontimeout [as _onTimeout] (timers.js:341:34)
at tryOnTimeout (timers.js:232:11)
at Timer.listOnTimeout (timers.js:202:5)
Hope the information is not vague, if you need more, please let me know. Thanks!
I Think the error is in this file, because i tried debugging and from the rabbitmq server, the callback is being called and it has the correlation id as well as the reply to variable, so the request is not getting picked up here.
var amqp = require('amqp')
, crypto = require('crypto');
var TIMEOUT=8000;
var CONTENT_TYPE='application/json';
var CONTENT_ENCODING='utf-8';
var self;
exports = module.exports = AmqpRpc;
function AmqpRpc(connection){
self = this;
this.connection = connection;
this.requests = {};
this.response_queue = false;
}
AmqpRpc.prototype.makeRequest = function(queue_name, content, callback){
self = this;
var correlationId = crypto.randomBytes(16).toString('hex');
var tId = setTimeout(function(corr_id){
callback(new Error("timeout " + corr_id));
delete self.requests[corr_id];
}, TIMEOUT, correlationId);
var entry = {
callback:callback,
timeout: tId
};
self.requests[correlationId]=entry;
self.setupResponseQueue(function(){
self.connection.publish(queue_name, content, {
correlationId:correlationId,
contentType:CONTENT_TYPE,
contentEncoding:CONTENT_ENCODING,
replyTo:self.response_queue});
});
};
AmqpRpc.prototype.setupResponseQueue = function(next){
if(this.response_queue) return next();
self = this;
self.connection.queue('', {exclusive:true}, function(q){
self.response_queue = q.name;
q.subscribe(function(message, headers, deliveryInfo, m){
var correlationId = m.correlationId;
if(correlationId in self.requests){
var entry = self.requests[correlationId];
clearTimeout(entry.timeout);
delete self.requests[correlationId];
entry.callback(null, message);
}
});
return next();
});
};
This is the code for your make_request() in client.js file:
var amqp = require('amqp');
var connection = amqp.createConnection({host:'127.0.0.1'});
var rpc = new (require('./amqprpc'))(connection);
function make_request(queue_name, msg_payload, callback){
rpc.makeRequest(queue_name, msg_payload, function(err, response){
if(err)
console.error(err);
else{
console.log("response", response);
callback(null, response);
}
});
}
exports.make_request = make_request;
Look at what happens when you have an err on rpc.makeRequest():
rpc.makeRequest(queue_name, msg_payload, function(err, response){
if(err)
console.error(err);
//
//HERE: should be a callback call here.
//
else{
console.log("response", response);
callback(null, response);
}
});
This could be why you are getting a timeout. I hope it helps.
There wasn't a problem with rabbitMQ but with my queries in the handle request and after responding to the request.
For others coming with this problem, check and double check every statement, as the error will not show in the console, but will only show a timeout

Socket.IO server not receiving message from client

I'm playing around with Node, Socket.IO and BDD by creating a chat application. During one of the tests, I get a timeout error stating:
Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.
The affected test is
it('#must be able to receive a message', function(done)
{
chatterServer.on('chatterMessage', function(data)
{
console.log('Incoming message!');
expect(data).to.have.property('message');
expect(data.message).to.be('Hello, world!');
done();
});
console.log('Sending message!');
chatterClient.send('chatterMessage', { message: 'Hello, world!' });
console.log('Sent!');
});
I found that the cause of this issue is that the chatterMessage event is not being caught by the server. Whilst I did specify it.
The console's output is:
Sending message!
Sent!
Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.
I'm probably doing something wrong. I'm not too familiar with Node and Socket.IO, so I'm sorry if this question is very obvious.
I looked around Google with the search terms 'socket.io server not receiving from client', but from what I found, nothing helped me to solve my issue so far.
I did however try the solution in this question, but that didn't fix it for me.
I'm using Mocha and expect.js
The complete test is:
var util = require('util');
var Chatter = require('../src/index');
var ChatterServer = Chatter.Server;
var ChatterClient = Chatter.Client;
var express = require('express');
var expect = require('expect.js');
var socketIO = require('socket.io');
var socketIOClient = require('socket.io-client');
var host = 'http://localhost';
var port = 8080;
describe('Chatter', function()
{
'use strict';
var chatterServer;
var chatterClient;
var server;
before(function()
{
var app = express();
server = app.listen(port);
});
beforeEach(function()
{
chatterServer = new ChatterServer(socketIO(server));
chatterClient = new ChatterClient(socketIOClient, util.format('%s:%s', host, port.toString()));
});
...
it('#must be able to receive a message', function(done)
{
chatterServer.on('chatterMessage', function(data)
{
console.log('Incoming message!');
expect(data).to.have.property('message');
expect(data.message).to.be('Hello, world!');
done();
});
console.log('Sending message!');
chatterClient.send('chatterMessage', { message: 'Hello, world!' });
console.log('Sent!');
});
});
My Client (ChatterClient) is:
(function()
{
'use strict';
function Client(socketIO, url)
{
this.socketIO = socketIO(url);
}
Client.prototype.send = function(event, data)
{
this.socketIO.emit(event, data);
};
Client.prototype.on = function(event, callback)
{
this.socketIO.on(event, callback);
};
if (module !== undefined && module.hasOwnProperty('exports')) {
module.exports = Client;
} else {
window.Chatter = {
Client: Client,
};
}
}());
The Server (ChatterServer) is:
(function()
{
'use strict';
function Server(socketIO)
{
this.socketIO = socketIO;
this.connectedUsers = {};
this.on('connection', (function(user)
{
var userID = user.client.id;
this.connectedUsers[userID] = user;
user.emit('chatterConnectionAcknowledged', { id: userID });
}).bind(this));
}
Server.prototype.on = function(event, handler)
{
this.socketIO.on(event, handler);
};
module.exports = Server;
}());
You need to change your code in two sides.
First side, you will need to listen incoming socket connections on the socketIO object. (see the emphasized code below)
//.. some code
function Server(socketIO)
{
this.socketIO = socketIO;
this.connectedUsers = {};
this.socketIO.on('connection', (function(user)
{
var userID = user.client.id;
this.connectedUsers[userID] = user;
user.emit('chatterConnectionAcknowledged', { id: userID });
}).bind(this));
}
//.. some code
Second side, when you are adding new events to listen on the server, you need to bind those events to the sockets since they are ones that are going to listen when events are emitted from the socket clients.
Server.prototype.on = function (event, handler) {
Object.keys(this.connectedUsers).map(function (key) {
this.connectedUsers[key].on(event, handler);
}.bind(this));
};

Trying to make my own RxJs observable

I'm trying to convert an existing API to work with RxJS... fairly new to node, and very new to RxJs, so please bear with me.
I have an existing API (getNextMessage), that either blocks (asynchronously), or returns a new item or error via a node-style (err, val) callback, when the something becomes available.
so it looks something like:
getNextMessage(nodeStyleCompletionCallback);
You could think of getNextMessage like an http request, that completes in the future, when the server responds, but you do need to call getNextMessage again, once a message is received, to keep getting new items from the server.
So, in order to make it into an observable collection, I have to get RxJs to keep calling my getNextMessage function until the subscriber is disposed();
Basically, I'm trying to create my own RxJs observable collection.
The problems are:
I don't know how to make subscriber.dispose() kill the async.forever
I probably shouldn't be using async.forever in the first place
I'm not sure I should be even getting 'completed' for each message - shouldn't that be at the end of a sequence
I'd like to eventually remove the need for using fromNodeCallback, to have a first class RxJS observable
Clearly I'm a little confused.
Would love a bit of help, thanks!
Here is my existing code:
var Rx = require('rx');
var port = require('../lib/port');
var async = require('async');
function observableReceive(portName)
{
var observerCallback;
var listenPort = new port(portName);
var disposed = false;
var asyncReceive = function(asyncCallback)
{
listenPort.getNextMessage(
function(error, json)
{
observerCallback(error, json);
if (!disposed)
setImmediate(asyncCallback);
}
);
}
return function(outerCallback)
{
observerCallback = outerCallback;
async.forever(asyncReceive);
}
}
var receive = Rx.Observable.fromNodeCallback(observableReceive('rxtest'));
var source = receive();
var subscription = source.forEach(
function (json)
{
console.log('receive completed: ' + JSON.stringify(json));
},
function (error) {
console.log("receive failed: " + error.toString());
},
function () {
console.log('Completed');
subscription.dispose();
}
);
So here's probably what I would do.
var Rx = require('Rx');
// This is just for kicks. You have your own getNextMessage to use. ;)
var getNextMessage = (function(){
var i = 1;
return function (callback) {
setTimeout(function () {
if (i > 10) {
callback("lawdy lawd it's ova' ten, ya'll.");
} else {
callback(undefined, i++);
}
}, 5);
};
}());
// This just makes an observable version of getNextMessage.
var nextMessageAsObservable = Rx.Observable.create(function (o) {
getNextMessage(function (err, val) {
if (err) {
o.onError(err);
} else {
o.onNext(val);
o.onCompleted();
}
});
});
// This repeats the call to getNextMessage as many times (11) as you want.
// "take" will cancel the subscription after receiving 11 items.
nextMessageAsObservable
.repeat()
.take(11)
.subscribe(
function (x) { console.log('next', x); },
function (err) { console.log('error', err); },
function () { console.log('done'); }
);
I realize this is over a year old, but I think a better solution for this would be to make use of recursive scheduling instead:
Rx.Observable.forever = function(next, scheduler) {
scheduler = scheduler || Rx.Scheduler.default,
//Internally wrap the the callback into an observable
next = Rx.Observable.fromNodeCallback(next);
return Rx.Observable.create(function(observer) {
var disposable = new Rx.SingleAssignmentDisposable(),
hasState = false;
disposable.setDisposable(scheduler.scheduleRecursiveWithState(null,
function(state, self) {
hasState && observer.onNext(state);
hasState = false;
next().subscribe(function(x){
hasState = true;
self(x);
}, observer.onError.bind(observer));
}));
return disposable;
});
};
The idea here is that you can schedule new items once the previous one has completed. You call next() which invokes the passed in method and when it returns a value, you schedule the next item for invocation.
You can then use it like so:
Rx.Observable.forever(getNextMessage)
.take(11)
.subscribe(function(message) {
console.log(message);
});
See a working example here

How to test node.js websocket server?

I'm using sockjs with standard configuration.
var ws = sockjs.createServer();
ws.on('connection', function(conn) {
conn.on('data', function(message) {
wsParser.parse(conn, message)
});
conn.on('close', function() {
});
});
var server = http.createServer(app);
ws.installHandlers(server, {prefix:'/ws'});
server.listen(config.server.port, config.server.host);
wsParser.parse function works like this:
function(conn, message) {
(...)
switch(message.action) {
case "titleAutocomplete":
titleAutocomplete(conn, message.data);
break;
(...) // a lot more of these
}
Each method called in switch sends back a message to client.
var titleAutocomplete = function(conn, data) {
redis.hgetall("titles:"+data.query, function(err, titles){
if(err) ERR(err);
if(titles) {
var response = JSON.stringify({"action": "titleAutocomplete", "data": {"titles": titles}});
conn.write(response);
}
})
};
Now my problem is that I'd like to make tests for my code (better late than never I guess) and I have no idea how to do it. I started writing normal http tests in with mocha + supertest but I just don't know how to handle websockets.
I'd like to have only one websocket connection to reuse through all tests, I'm binding the websocket connection with user session after first message and I want to test that persistence as well.
How do I make use of ws client's onmessage event and utilize it in my tests? How the tests can tell apart received messages and know which one they are supposed to wait for?
Collegue at work asked if it really needs to be a client connection or would it be possible to just mock it up. It turned out it was the way to go. I wrote a little helper class wsMockjs
var wsParser = require("../wsParser.js");
exports.createConnectionMock = function(id) {
return {
id: id,
cb: null,
write: function(message) {
this.cb(message);
},
send: function(action, data, cb) {
this.cb = cb;
var obj = {
action: action,
data: data
}
var message = JSON.stringify(obj);
wsParser.parse(this, message);
},
sendRaw: function(message, cb) {
this.cb = cb;
wsParser.parse(this, message);
}
}
}
Now in my mocha test I just do
var wsMock = require("./wsMock.js");
ws = wsMock.createConnectionMock("12345-67890-abcde-fghi-jklmn-opqrs-tuvwxyz");
(...)
describe('Websocket server', function () {
it('should set sessionId variable after handshake', function (done) {
ws.send('handshake', {token: data.token}, function (res) {
var msg = JSON.parse(res);
msg.action.should.equal('handshake');
msg.data.should.be.empty;
ws.should.have.property('sessionId');
ws.should.not.have.property('session');
done();
})
})
it('should not return error when making request after handshake', function (done) {
ws.send('titleAutocomplete', {query: "ter"}, function (res) {
var msg = JSON.parse(res);
msg.action.should.equal('titleAutocomplete');
msg.data.should.be.an.Object;
ws.should.have.property('session');
done();
})
})
})
It works like a charm and persist connection state and variables between requests.

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