Develop Reference

Mongoose findOneAndUpdate doesn't find (or update) in Node

I'm trying to add user input (url's) to a database with Mongoose but also checking if the added data already exists. Instead it seems to be creating a new model every time.
This shows the res.json(input) on screen, not the test json
var mongo = require('mongodb');
var mongoose = require('mongoose');
var cors = require('cors');
// Basic Configuration
var port = process.env.PORT || 3000;
process.env.DB_URI="omg it's my secret url"
// Connect to DB.
mongoose.connect(process.env.DB_URI, { useNewUrlParser: true, useUnifiedTopology: true }).
catch(error => handleError(error));
mongoose.connection.on('error', err => {
console.log(err);
});
app.use(cors());
//First we create a schema and Model in MongoDB.
const urlSchema = new mongoose.Schema({
original_url: String,
short_url: Number
});
const urlModel = mongoose.model('urlModel', urlSchema);
app.post(/PATH, function(req, res, done) {
//Now we check if the input-url was actually valid.
if(!/(^https:\/\/)/.test(req.body.url)){
res.json({error: "Invalid url"});
}
//If it's valid we will start creating a model in the DB.
else {
var userUrl = req.body.url;
var urlNumber = 0;
var input = new urlModel({
original_url: userUrl
});
//Now we check if the url was already added to the database and return a new or updated item.
urlSchema.pre('save', function (next) {
var query = {'original_url': userUrl };
urlModel.findOneAndUpdate(query, userUrl, {upsert: true}, function(err, doc) {
if (err) return res.send(500, {error: err});
res.json({'test': 'test'});
});
});
res.json(input);
urlNumber++;
input.save(function(err, data) {
if (err) return console.log(err);
done(null, data);
});
};
});
As you can see I also have a problem updating the number that I want to attach to the url in the database, since I re-assign 0 to urlNumber at the beginning of the call. Must be because it's late but I can't seem to find a way to update that number correctly. I tried two variables and checking them against each other and an if(urlNumber > 0), but that's a problem I'm still solving. Seems so simple..
Anyway the question here is: why doesn't findOneAndUpdate seem to update? The returned res.json(input) shows a new '_id' every time, which tells me it does actually create new models every run.
Example returns
#1
{
_id: eksdjh3948wryeids293ren12;
original_url: "https://www.correct.com"
short_url: 0
}
#2
{
_id: eksdjh3948wryeids293ren13; // (<----- NEW NUMBER)
original_url: "https://www.correct.com"
short_url: 0
}

Your pre('save' function(next) {}) hook isn't calling next()

Turns out the .pre hook doesn't work with findOneAndUpdate! If I just remove that, the code now works as expected.

How to wait until mysql query is done and then continue to run the script?

I've made a class in which the constructor is being declared mostly by a mySQL query that looks like that:
constructor(username) {
this.mysql = require('mysql');
// create a connection variable with the required details
this.con = this.mysql.createConnection({
host: "localhost", // ip address of server running mysql
user: "root", // user name to your mysql database
password: "", // corresponding password
database: "db" // use the specified database
});
this.username = username;
this._password = "";
this.con.query("SELECT * FROM users WHERE username = ?", this.username, function (err, result, fields) {
if (err) throw err;
this._password = result[0].password;
});
}
get password() {
return this._password;
}
The issue is , when I'm declaring the class like that:
const user= require("./user.js");
let bot = new user("user1");
console.log(user.password();
The code first accessing the get and getting undefined , and only after the the query is done.
How can I fix it?

You can't make a constructor asynchronous, that's not supported by Javascript.
What you can do is create an asynchronous createUser function that returns a user, and modify the constructor of your User class to take the data returned from the database.
Something like:
class User {
// Synchronous constructor
constructor(mysqlData) {
this._password = mysqlData.password;
}
}
// Asynchronous create user function
function createUser(name, callback) {
con.query('your query', [], function (err, result) {
if (err) return callback(err); // Traditional error-first callback
const user = new User(result[0]);
callback(null, user);
}
}
// Create the user and then do something once the user is created
createUser('user1', function (err, user) {
if (err) throw err;
console.log(user.password());
});
Unrelated tip: look into Promises and async/await, they are so much nicer to use than callbacks. Then your createUser function would look something like this (notice the await keyword instead of a callback for the query):
async function createUser(name) {
const result = await con.query('your query', []);
const user = new User(result[0]);
return user;
}
And then you can do const user = await createUser('user1'); from another async function (you can only use await inside of an async function).
Keep in mind that for this to work, you need:
A runtime that supports async/await (Node 7.6+ or a modern browser), or Babel to transpile the code so it can run in older runtimes & browsers.
A mysql client that supports promises (there are wrappers on npm for most packages).

NodeJS MySQL Async- Return object back to caller function

I am brand new to NodeJS and am struggling to find a solution to making a reusable function to execute a query (passed via a parameter) and then simply return the response to the caller. I want to do it this way as there will be over 100 functions requiring database queries and it'll help reduce code size.
I’ve tried the following as a very primitive test, but the dbA_Read_Data() function always returns undefined, because it's asynchronous. However, 6 days later, and over 15 alternative callback/promise solutions that work for some haven't worked for me and I am no closer to solving this issue and accomplishing the following.
const { Databases } = require('../../utils/enums');
var mysql = require('mysql');
function getAllUsers() {
//This function would be called when an endpoint is hit in my HapiJS system.
var myQuery = "SELECT * FROM Users WHERE Account_Status== 'ACTIVE' ";
var response = dbA_Read_Data(myQuery);
return response;
}
//dbA => website database, contains users/permissions/etc
//Other databases... you get the idea
function dbA_Read_Data(query) {
dbConn = createConnection("localhost", Databases.db_A.name, Databases.db_A.username, Databases.db_A.password);
dbConn.connect();
dbConn.query(query, function(err, rows, fields) {
if (err) throw err;
var myResponseObject = {
query: query,
data: {
count: rows.length,
records: rows
}
}
});
}
function createConnection(host, database, user, password) {
var connection = mysql.createConnection({
host: host,
user: user,
password: password,
database: database
});
return connection;
}
How do I get the function dbA_Read_Data(query) to return the response object to the caller function?

As in the comments section, the database call conn.query is asynchronous so it is impossible to simply return the result. In order to obtain the result of this query and operate on it, you could use a Promise.
I suppose your dbA_Read_Data(query) function could look like that:
function dbA_Read_Data(query){
var dbConn = createConnection("localhost", Databases.db_A.name, Databases.db_A.username, Databases.db_A.password);
dbConn.connect();
return new Promise(function(resolve, reject){
dbConn.query(query, function(err, rows, fields) {
if ( err ) {
reject(err);
} else {
var myResponseObject = {
query: query,
data: {
count: rows.length,
records: rows
}
}
resolve(myResponseObject);
}
});
});
}
Then your getAllUsers() function call would require .then() in order to obtain the results:
function getAllUsers(){
var myQuery = "SELECT * FROM Users WHERE Account_Status== 'ACTIVE' ";
return dbA_Read_Data(myQuery).then(function(result){
return result;
}).catch(function(error){
// handle the error properly here...
console.log('error in database operation');
});
}
getAllUsers().then(function(users){
// do something with the result...
console.log(users);
});

NodeJS is asynchronous and my code doesn't run in the order I am expecting

postRegistrationHandler: function (account, req, res, next) {
console.log('postRegistrationHandler activated');
account.getCustomData(function(err, data) {
if (err) {
console.log(err.toString, "error string");
return next(err);
} else {
data.mongo_id = userCreationCtrl(account);
data.save();
next();
}
});
},
This function almost works properly, but the line:
data.save();
runs before the previous line finishes which means that the data I want to save isn't present at the appropriate time.
data.mongo_id = userCreationCtrl(account);
This line calls a function that creates a mongoDB document with information in the account object and then returns the _id (which is what I am trying to save.
I thought maybe using a .then() would help but that seems to be unavailable here for some reason. If anyone sees something I'm missing, that would be quite helpful. Thank you!
Here is the userCreationCtrl file as requested:
var UserSchema = require('./../models/UserModel.js');
var createNewUser = function (account, res, next){
// We will return mongoId after it is created by submitting a newUser
var mongoId = "";
// Save StormpathID (last 22 characters of account.href property)
var newStormpathId = account.href.slice(account.href.length - 22);
console.log('stormpath ID:', newStormpathId, 'just registered!');
console.log(account);
// Create new user from model by recycling info from the Stormpath registration form and include the stormpathId as well.
var newUser = new UserSchema({
stormpathId: newStormpathId,
firstName: account.givenName,
lastName: account.surname,
email: account.email,
street: account.street,
city: account.city,
zip: account.zip
});
// This saves the user we just created in MongoDB
newUser.save(function(err, result){
console.log(result);
if (err) {
console.error(err);
}
else {
console.log("User created in MongoDB, attempting to return mongoDB _id to stormpath customData");
// Keep track of the new user's mongo _id so we can return it to the previous function and save it as Stormpath custom data.
mongoId = result._id;
console.log(mongoId, "mongoid");
return result._id;
}
});
};
module.exports = createNewUser;

You have userCreationCtrl expecting 3 arguments, account, res, and next. next is the callback that should be called after the user is created so instead of return result._id you should call next like so:
// inside of createNewUser()
newUser.save(function(err, result){
console.log(result);
if (err) {
console.error(err);
}
else {
console.log("User created in MongoDB, attempting to return mongoDB _id to stormpath customData");
// Keep track of the new user's mongo _id so we can return it to the previous function and save it as Stormpath custom data.
mongoId = result._id;
console.log(mongoId, "mongoid");
// IMPORTANT change to make it all work...
// get rid of return result._id because its not doing anything
// pass the value to your callback function instead of returning the value
next(null, result._id);
}
});
then calling code in postRegistrationHandler should look like this:
account.getCustomData(function(err, data) {
if (err) {
console.log(err.toString, "error string");
return next(err);
} else {
// pass in a callback as the 3rd parameter that will be called by newUser.save() when its finished
userCreationCtrl(account, null, function(err, resultId) {
data.save();
next();
});
}
});

Mongoose - Create document if not exists, otherwise, update- return document in either case

I'm looking for a way to refactor part of my code to be shorter and simpler, but I don't know Mongoose very well and I'm not sure how to proceed.
I am trying to check a collection for the existence of a document and, if it doesn't exist, create it. If it does exist, I need to update it. In either case I need to access the document's contents afterward.
What I've managed to do so far is query the collection for a specific document and, if it's not found, create a new document. If it is found, I update it (currently using dates as dummy data for this). From there I can access either the found document from my initial find operation or the newly saved document and this works, but there must be a better way to accomplish what I'm after.
Here's my working code, sans distracting extras.
var query = Model.find({
/* query */
}).lean().limit(1);
// Find the document
query.exec(function(error, result) {
if (error) { throw error; }
// If the document doesn't exist
if (!result.length) {
// Create a new one
var model = new Model(); //use the defaults in the schema
model.save(function(error) {
if (error) { throw error; }
// do something with the document here
});
}
// If the document does exist
else {
// Update it
var query = { /* query */ },
update = {},
options = {};
Model.update(query, update, options, function(error) {
if (error) { throw error; }
// do the same something with the document here
// in this case, using result[0] from the topmost query
});
}
});
I've looked into findOneAndUpdate and other related methods but I'm not sure if they fit my use case or if I understand how to use them correctly. Can anyone point me in the right direction?
(Probably) Related questions:
How to check if that data already exist in the database during update (Mongoose And Express)
Mongoose.js: how to implement create or update?
NodeJS + Mongo: Insert if not exists, otherwise - update
Return updated collection with Mongoose
Edit
I didn't come across the question pointed out to me in my searching, but after reviewing the answers there I've come up with this. It's certainly prettier, in my opinion, and it works, so unless I'm doing something horribly wrong I think my question can probably be closed.
I would appreciate any additional input on my solution.
// Setup stuff
var query = { /* query */ },
update = { expire: new Date() },
options = { upsert: true };
// Find the document
Model.findOneAndUpdate(query, update, options, function(error, result) {
if (!error) {
// If the document doesn't exist
if (!result) {
// Create it
result = new Model();
}
// Save the document
result.save(function(error) {
if (!error) {
// Do something with the document
} else {
throw error;
}
});
}
});

You are looking for the new option parameter. The new option returns the newly created document(if a new document is created). Use it like this:
var query = {},
update = { expire: new Date() },
options = { upsert: true, new: true, setDefaultsOnInsert: true };
// Find the document
Model.findOneAndUpdate(query, update, options, function(error, result) {
if (error) return;
// do something with the document
});
Since upsert creates a document if not finds a document, you don't need to create another one manually.

Since you wish to refactor parts of your code to be shorter and simpler,
Use async / await
Use .findOneAndUpdate() as suggested in this answer
let query = { /* query */ };
let update = {expire: new Date()};
let options = {upsert: true, new: true, setDefaultsOnInsert: true};
let model = await Model.findOneAndUpdate(query, update, options);

///This is simple example explaining findByIDAndUpdate from my code added with try catch block to catch errors
try{
const options = {
upsert: true,
new: true,
setDefaultsOnInsert: true
};
const query = {
$set: {
description: req.body.description,
title: req.body.title
}
};
const survey = await Survey.findByIdAndUpdate(
req.params.id,
query,
options
).populate("questions");
}catch(e){
console.log(e)
}

Here is an example I am using. I have to return custom responses for UI updates etc. This can be even shorter. User is
const UserScheme = mongoose.Schema({
_id: String,
name: String,
city: String,
address: String,
},{timestamps: true});
const User = mongoose.model('Users', UserScheme);
async function userUpdateAdd(data){
var resp = '{"status": "error"}';
if(data){
var resp = await User.updateOne({ _id: data._id }, data).then(function(err, res){
console.log("database.userUpdateAdd -> Update data saved in database!");
if(err){
var errMessage = err.matchedCount == 0 ? "User Record does not exist, will create new..." : "Record not updated";
// If no match, create new
if(err.matchedCount == 0){
const create_user = new User(data);
resp = create_user.save().then(function(){
console.log("database.userUpdateAdd -> Data saved to database!");
return '{"status":"success", "message": "New User added successfully"}';
});
return resp;
}
// Exists, return success update message
if(err.matchedCount == 1){
return '{"status": "success", "message" : "Update saved successfully"}';
} else {
return '{"status": "error", "code": "' + err.modifiedCount + '", "message": "' + errMessage + '"}';
}
}
})
.catch((error) => {
//When there are errors We handle them here
console.log("database.userUpdateAdd -> Error, data not saved! Server error");
return '{"status": "error", "code": "400", "message": "Server error!"}';
});
}
return resp;
}

Here's an example:
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/rsvp', {useNewUrlParser: true, useUnifiedTopology: true});
const db = mongoose.connection;
db.on('error', () => {
console.log('mongoose connection error');
});
db.once('open', () => {
console.log('mongoose connected successfully');
});
const rsvpSchema = mongoose.Schema({
firstName: String,
lastName: String,
email: String,
guests: Number
});
const Rsvp = mongoose.model('Rsvp', rsvpSchema);
// This is the part you will need... In this example, if first and last name match, update email and guest number. Otherwise, create a new document. The key is to learn to put "upsert" as the "options" for the argument.
const findRsvpAndUpdate = (result, callback) => {
Rsvp.findOneAndUpdate({firstName: result.firstName, lastName: result.lastName}, result, { upsert: true }, (err, results) => {
if (err) {
callback(err);
} else {
callback(null, results);
}
})
};
// From your server index.js file, call this...
app.post('/rsvps', (req, res) => {
findRsvpAndUpdate(req.body, (error, result) => {
if (error) {
res.status(500).send(error);
} else {
res.status(200).send(result);
}
})
});