Develop Reference

unable to catch any form of error or response from firebase notification callback function in Node js

I am using the package "fcm-node" in order to send notifications to certain device id.
the sendNotification function is as follows:
const FCM = require('fcm-node');
const serverKey = process.env.SERVER_KEY;
const fcm = new FCM(serverKey);
function sendNotification(registrationToken, title, body, type, key) {
const message = {
to: registrationToken,
collapse_key: key,
notification: {
title: title,
body: body,
delivery_receipt_requested: true,
sound: `ping.aiff`
},
data: {
type: type,
my_key: key,
}
};
fcm.send(message, function (err, value) {
if (err) {
console.log(err);
return false;
} else {
console.log(value);
return value;
}
});
};
module.exports = {
sendNotification
};
The api function I use to call this function is as follows:
router.get('/test', async (req, res, next) => {
const promise = new Promise((resolve, reject) => {
let data = sendNotification('', 'dfsa', 'asds', 'dfas', 'afsdf');
console.log(data)
if (data == false) reject(data);
else resolve(data);
});
promise
.then((data) => { return res.status(200).send(data); })
.catch((data) => { return res.status(500).send(data) })
});
When I console.log the "err" and "value" from the sendNotification, I get either of the followings:
{"multicast_id":4488027446433525506,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1652082785265643%557c6f39557c6f39"}]};
{"multicast_id":8241007545302148303,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"InvalidRegistration"}]}
In case it is successful, I made sure that the device is receiving the notification.
The problem is in the api's data. It is always "undefined" and weither send notification is successful or not I get the 200 Ok status.
What seems to be the problem?

You can't return anything from the function (err, value) {} callback of a node-style asynchrnous function.
Your sendNotification() function needs to return a promise. util.promisify() makes the conversion from a node-style asynchronous function to a promise-returning asynchronous function convenient. Note the return, it's important:
const FCM = require('fcm-node');
const serverKey = process.env.SERVER_KEY;
const fcm = new FCM(serverKey);
const { promisify } = require('util');
fcm.sendAsync = promisify(fcm.send);
function sendNotification(registrationToken, title, body, type, key) {
return fcm.sendAsync({
to: registrationToken,
collapse_key: key,
notification: {
title: title,
body: body,
delivery_receipt_requested: true,
sound: `ping.aiff`
},
data: {
type: type,
my_key: key,
}
});
}
module.exports = {
sendNotification
};
Now you can do what you had in mind
router.get('/test', async (req, res, next) => {
try {
const data = await sendNotification('', 'dfsa', 'asds', 'dfas', 'afsdf');
return res.status(200).send(data);
} catch (err) {
return res.status(500).send(err);
}
});

Maybe it will help, at first try to return your response (the promise) in sendNotification, as actually you have a void function, that's why it's always undefined and after in your route
router.get('/test', async (req, res, next) => {
try {
const data = sendNotification('', 'dfsa', 'asds', 'dfas', 'afsdf');
if (data) {
return res.status(200).send(data);
}
} catch(err) {
return res.status(500).send(err);
}
});

Node JS throwing cannot set headers after they are sent to the client, after using mongoose.removeOne

I have a method that deletes products and before it does it check if the user who is trying to delete the product is the user who created it. When i execute it with Insomnia it successfully removes the product but i get an error on the console saying cannot set headers after they are sent to the client.
My method:
exports.deleteProduct = (req, res) => {
const id = req.params.productId;
Product.deleteOne({ _id: id, userId: req.user._id }, () => {
return res.status(401).json("Not authorized");
})
.then(() => {
return res.status(200).json("Product deleted");
})
.catch((err) => {
return res.status(500).json({
error: err,
});
});
};
I'm pretty sure this is happening because I'm chaining a .then() and .catch() after executing it.
I tried to do this but it didn't work because the err parameter that I'm sending to the callback function is null.:
exports.deleteProduct = (req, res) => {
const id = req.params.productId;
Product.deleteOne({ _id: id, userId: req.user._id }, (err) => {
if (err) {
return res.status(401).json("Not authorized");
}
return res.status(200).json("Product deleted");
});
};
When i tried this second approach I always got the 200 status, meanwhile the product didn't delete.
Any idea how to deal with this?

You can try something like this:
Product.deleteOne({ _id: id, userId: req.user._id }, (err, result) => {
if(err) {
return "something"
}
return "something else"
});
or: in async / await way
try {
await Product.deleteOne({ _id: id, userId: req.user._id });
} catch (err) {
// handle error here
}
By the way, why you are passing userId at the deleteOne method?

Using Multiple FindOne in Mongodb

I am trying to extend the amount of fields that our API is returning. Right now the API is returning the student info by using find, as well as adding some information of the projects by getting the student info and using findOne to get the info about the project that the student is currently registered to.
I am trying to add some information about the course by using the same logic that I used to get the project information.
So I used the same findOne function that I was using for Projects and my logic is the following.
I created a variable where I can save the courseID and then I will put the contents of that variable in the temp object that sending in a json file.
If I comment out the what I added, the code works perfectly and it returns all the students that I require. However, when I make the additional findOne to get information about the course, it stops returning anything but "{}"
I am going to put a comment on the lines of code that I added, to make it easier to find.
Any sort of help will be highly appreciated!
User.find({
isEnrolled: true,
course: {
$ne: null
}
},
'email pantherID firstName lastName project course',
function(err, users) {
console.log("err, users", err, users);
if (err) {
return res.send(err);
} else if (users) {
var userPromises = [];
users.map(function(user) {
userPromises.push(new Promise(function(resolve, reject) {
///////// Added Code START///////
var courseID;
Course.findOne({
fullName: user.course
}, function(err, course) {
console.log("err, course", err, course);
if (err) {
reject('')
}
courseID = course ? course._id : null
//console.log(tempObj)
resolve(tempObj)
}),
///// ADDED CODE END //////
Project.findOne({
title: user.project
}, function(err, proj) {
console.log("err, proj", err, proj);
if (err) {
reject('')
}
//Course ID, Semester, Semester ID
//map to custom object for MJ
var tempObj = {
email: user.email,
id: user.pantherID,
firstName: user.firstName,
lastName: user.lastName,
middle: null,
valid: true,
projectTitle: user.project,
projectId: proj ? proj._id : null,
course: user.course,
courseId: courseID
}
//console.log(tempObj)
resolve(tempObj)
})
}))
})
//async wait and set
Promise.all(userPromises).then(function(results) {
res.json(results)
}).catch(function(err) {
res.send(err)
})
}
})

using promise could be bit tedious, try using async, this is how i would have done it.
// Make sure User, Course & Project models are required.
const async = require('async');
let getUsers = (cb) => {
Users.find({
isEnrolled: true,
course: {
$ne: null
}
}, 'email pantherID firstName lastName project course', (err, users) => {
if (!err) {
cb(null, users);
} else {
cb(err);
}
});
};
let findCourse = (users, cb) => {
async.each(users, (user, ecb) => {
Project.findOne({title: user.project})
.exec((err, project) => {
if (!err) {
users[users.indexOf(user)].projectId = project._id;
ecb();
} else {
ecb(err);
}
});
}, (err) => {
if (!err) {
cb(null, users);
} else {
cb(err);
}
});
};
let findProject = (users, cb) => {
async.each(users, (user, ecb) => {
Course.findOne({fullName: user.course})
.exec((err, course) => {
if (!err) {
users[users.indexOf(user)].courseId = course._id;
ecb();
} else {
ecb(err);
}
});
}, (err) => {
if (!err) {
cb(null, users);
} else {
cb(err);
}
});
};
// This part of the code belongs at the route scope
async.waterfall([
getUsers,
findCourse,
findProject
], (err, result) => {
if (!err) {
res.send(result);
} else {
return res.send(err);
}
});
Hope this gives better insight on how you could go about with multiple IO transactions on the same request.

Passing an Array to Jade/Pug Route in Express

I'm new to express and pug so forgive me if this is a noob question but how do I pass the array I created in one function to the route that will render the pug template. I ultimately want to loop though the array and render it as a table.
My code - first I create the array from the data received from a file with the lodash map method. *EDIT - added full code structure -
fs.readFile(file, 'utf8', function (err, data) {
if (err) {
console.log('Error: ' + err);
return;
}
var data = JSON.parse(data);
var newEventList = data.events.map(events => ({
id: events.id ,
name: events.name ,
venue: events.place.name ,
address: events.place.location.street + " " +
events.place.location.city + " " + events.place.location.zip ,
coverPicture: events.coverPicture ,
description: events.description ,
startTime: events.startTime ,
endTime: events.endTime
}));
});
So now I have an array of objects called newEventList.
My route for pug is
app.get('/', function (req, res, newEventList) {
res.render('index', { title: 'Hey', message: 'Hello there!',
newEventList
})
})
I added title and message to test my pug template.
in my Pug Template I have
h1= message
p= newEventList
but in the paragraph that is rendered I get a long error message -
function next(err) { // signal to exit route if (err && err === 'route') { return done(); } // signal to exit router if (err && err === 'router') { return done(err) } var layer = stack[idx++]; if (!layer) { return done(err); } if (layer.method && layer.method !== method) { return next(err); } if (err) { layer.handle_error(err, req, res, next); } else { layer.handle_request(req, res, next); } }
What am I doing wrong please?

From your route definition's callback, remove or rename newEventList as your third param.
In your example, newEventList is getting assigned to the done/next callback. Hence you're seeing a function being printed in your paragraph.
var newEventList = // Whatever value;
app.get('/', function (req, res) {
res.render('index', { title: 'Hey', message: 'Hello there!',
newEventList
})
})

Async.js series and node-mysql query's cant get rows

I am currently trying to run a set of MySQL query's in order using async.js series control flow function. But I keep receiving the following error:
throw err; // Rethrow non-MySQL errors
^
TypeError: Cannot read property 'status' of undefined
I have tested the query's in seperate functions outside the async.series and they are fine and give me back the data, the only reason I can think for the error is due to the async nature it doesn't have the data at that time hence the error E.G when I log the rows I get:
[]
[]
[]
Below is the Async function:
function SQLuserDataAsync() {
connection.getConnection(function (err, connection) {
async.series([
function (callback) {
connection.query('SELECT status FROM users WHERE name= ?;',
[userval],
function (err, rows) {
if (rows[0]['status']) {
console.log("Account Status: " + accountval);
} else {
console.log(err);
}
callback(null, 'one');
});
},
function (callback) {
connection.query('SELECT account_type FROM settings_tbl WHERE id=(SELECT id FROM users WHERE name= ?);',
[userval],
function (err, rows) {
if (rows[0]['account_type']) {
var acctype = rows[0]['account_type'];
console.log("Account Type: " + acctype);
} else {
console.log(err);
}
callback(null, 'two');
});
},
function (callback) {
connection.query('SELECT type FROM settings_tbl WHERE id=(SELECT id FROM users WHERE name= ?);',
[userval],
function (err, rows) {
if (rows[0]['type']) {
var type = rows[0]['type'];
console.log("Type: " + type);
} else {
console.log(err);
}
callback(null, 'three');
});
}
]);
connection.release();
});
}
Any suggestions as the reason for the error or what am doing wrong here?

You've missed the main callback function to the async.series function.
function SQLuserDataAsync() {
connection.getConnection(function (err, connection) {
async.series([
function (callback) {
// YOUR CODE
},
function (callback) {
// YOUR CODE
},
function (callback) {
// YOUR CODE
}
], function(error, results) { // <--- this is the main callback
connection.release();
});
});
}
You should call connection.release() inside the main callback, otherwise, the MySQL connection will be released/terminated before the queries are executed (due to the asynchronous nature the code).

if there is a user with defined in userval name it will work.
But let's simplify our code:
function SQLuserDataAsync(userval) {
connection.getConnection(function (err, connection) {
async.waterfall([
// getting user
function (next) {
connection.query(
'SELECT * FROM users WHERE name = ? LIMIT 1',
[userval],
function (err, result) {
next(err, result[0]); // passing user to next function
});
},
// getting settings of user, maybe user_id (not id) in query below
function (user, next) {
connection.query(
'SELECT * FROM settings_tbl WHERE id = ? LIMIT 1',
[user.id],
function (err, result) {
next(err, user, result[0]);
});
},
// handling both user and settings
function (user, settings, next) {
console.log('User: ', user);
console.log('Settings: ', settings);
connection.release();
}
]);
});
}
SQLuserDataAsync('someone');