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send data from db with and api build with express-generator code 200 no data

my database in mongoDb is connected to my nodeJS i can read it there my nodeJs api is connected to my client-side (in reactJS) and i can send data from my nodeJs api using express-generator to my client-side and is working but when i tried to send my mongoDb database to the client-side is not working( but i'm still getting status 200 but my array is not here . I can't figure out why? i cant see the db when i call the api in postman so i assume the error is in the server-side . If i had a consol.log i can see the db but when i use return it is not working and i cant see the data in postman
here my nodeJs code:
var mongodb = require('mongodb')
var MongoClient = mongodb.MongoClient
var connectionURL = 'mongodb://127.0.0.1:27017'
var databaseName = 'projet_Ecommerce';
const dataFromDb = () => {
MongoClient.connect(connectionURL, {
useNewUrlParser: true
}, (error, client) => {
if (error) {
return console.log('Unable to connect to database')
}
console.log('Connected correctly !');
var db = client.db(databaseName)
db.collection('product').find().toArray(function(error, data) {
if (error) {
return console.log('Unable to find the user')
}
return (data);
})
// Pointer - go to doc
// db.collection('tasks').find({completed: false}).toArray()
})
};
module.exports = dataFromDb
routres / index.js:
var express = require('express');
var router = express.Router();
const bodyParser = require('body-parser')
var dataC = require('../public/javascripts/dataFromDb')
// data = JSON.stringify(data);
// console.log(dataFromDb())
/* GET home page. */
router.get('/', function(req, res, next) {
//console.log(dataFromDb())
res.send(dataC())
});
//console.log(dataFromDb())
module.exports = router;
app.js:
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var cors = require("cors")
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var testAPIRouter = require("./routes/testAPI");
var app = express();
var bodyParser = require("body-parser")
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.use(cors());
app.use(logger('dev'));
app.use(express.json());
// app.use(bodyParser.urlencoded({ extended: true }));
app.use(express.urlencoded({
extended: false
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use("/testAPI", testAPIRouter);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
next(createError(404));
});
// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;
other files no change

How to handle timeout(--ms-- message) in nodejs

This photo shows --ms-- message. And in client side, I get timeout error.
I am trying to figure out where it occurs and why using try-catch and console.log but I can't find any.
This is 'routes/email.js'
var express = require('express');
var router = express.Router();
var db = require('../db');
var nodemailer = require("nodemailer");
var smtpTransport = nodemailer.createTransport({
service: 'Gmail',
auth: {
user: 'ssssss#gmail.com',
pass: 'SSSSSS'
}
});
router.get('/send', function(req, res, next) {
console.log('/send');
var email = decodeURI(req.query.to);
console.log(email);
var rand = Math.floor((Math.random() * 9000 + 1000));
var link="http://"+req.get("host")+"/email/verify?email="+email+"&num="+rand;
var mailOptions={
to : email,
subject : "Please confirm your Email account",
html : "Hello,<br> Please Click on the link to verify your email.<br>Click here to verify"
}
try{
smtpTransport.sendMail(mailOptions, function(error, response){
if(error){
console.log(error);
res.json({result:false,message:"Incorrect email", code:404});
}else{
console.log("Message sent:\n"+JSON.stringify(response, null, 2));
try{
console.log(JSON.stringify(db, null, 2));
var sql = "INSERT INTO email_verification(email, code) VALUES(?,?)";
var input = [email, rand];
db.get().query(sql, input, function(err, result){
if(err) res.json({result:false, message:"SQL error", code:403});
res.json({result:true, message:"Please check your email.", code:100});
});
// res.json({result:false, message:"DB ERROR", code:401});
}catch(e){
console.log(e);
}
}
});
}catch(e){
console.log(e);
}
});
module.exports = router;
db.get().query() part doesn't execute at all.
This is db.js.
const mariadb = require('mariadb');
var pool;
exports.connect = function(done){
console.log("Trying to connect DB...");
pool = mariadb.createPool({
host: 'localhost',
user: 'root',
password: 'ssss',
database:"SSSS",
connectionLimit: 100
});
}
exports.get = function(){
console.log("exports.get");
return pool;
}
The console.log("exports.get"); parts works fine.
This is app.js:
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var logger = require('morgan');
var db = require('./db');
//var passport = require('./passport');
//var auth = require('./routes/auth');
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');
db.connect(function(err){
console.log(err);
if(err){
console.log('Unable to connect to MariaDB.');
process.exit(1);
}
});
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', require("./routes/index"));
app.use('/email', require("./routes/email"));
// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(404);
});
// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;
I just used this db.jsand app.js file from my other project and it worked fine there. But I don't know why this time I have this problem.
Which part and why I am having this problem and how can I fix it?
It'd be easier to work with node.js if I can track the error easily. Figuring out the problematic part takes lots of time. Is there any module or tool for that?

Passing Mongo DB Object DB to Express Middleware

I am having problems trying to access the "DB" database object that is created when the MongoDB client module connects to my MongoDB database.
At the moment I am getting an error stating that, within data.js, 'db' is not defined. I understand why this is - the db object is not being "passed" through to the router and then subsequently through to the controller.
What is the best way to do this?
I have tried to pass the "db" object through to the router (dataRoutes.js) but I cannot figure how to make this accessible to the controller (data.js). Could someone please help?
Please note I have not included the other routes and controllers but they simply submit a Form via the POST method to /data/submit . The controller below is meant to write this form data to the MongoDB database.
Here is the relevant code:
app.js
var express = require('express');
var path = require('path')
var MongoClient = require('mongodb').MongoClient;
var bodyParser = require('body-parser');
var app = express();
var routes = require('./routes/index');
var dataRoutes = require('./routes/dataRoutes');
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
MongoClient.connect("mongodb://localhost:27017/m101", function(err, db) {
if(err) throw err;
console.log("Successfully connected to MongoDB.");
app.use('/', routes); // Use normal routes for wesbite
app.use('/data', dataRoutes);
app.get('/favicon.ico', function(req, res) {
res.send(204);
});
app.use(function(req, res, next) {
var err = new Error('Oops Page/Resource Not Found!');
err.status = 404;
next(err); //Proceed to next middleware
});
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
// update the error responce, either with the error status
// or if that is falsey use error code 500
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}
app.use(function(err, req, res, next) {
console.log('Error');
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});
var server = app.listen(3000, function() {
var port = server.address().port;
console.log("Express server listening on port %s.", port);
});
});
dataRoutes.js
// router
var express = require('express');
var router = express.Router();
// controller references
var ctrlsData = require('../controllers/data');
router.post('/submit', ctrlsData.submit);
module.exports = router;
data.js
var MongoClient = require('mongodb').MongoClient;
var sendJsonResponse = function(res, status, content) {
res.status(status);
res.json(content);
};
module.exports.submit = function(req, res) {
var title = req.body.title;
var year = req.body.year;
var imdb = req.body.imdb;
/*
console.log('submitted');
console.log(req.body);
sendJsonResponse(res, 201, {title,year,imdb});
*/
var title = req.body.title;
var year = req.body.year;
var imdb = req.body.imdb;
if ((title == '') || (year == '') || (imdb == '')) {
sendJsonResponse(res, 404, {
"message": "Title, Year and IMDB Reference are all required."
});
} else {
db.collection('movies').insertOne(
{ 'title': title, 'year': year, 'imdb': imdb },
function (err, r) {
if (err) {
sendJsonResponse(res, 400, err);
} else {
sendJsonResponse(res, 201, "Document inserted with _id: " + r.insertedId + {title,year,imdb});
}
}
);
}
};

Create a db variable that reference mongodb in app.js :
MongoClient.connect("mongodb://localhost:27017/m101", function(err, db) {
app.db = db;
//.....
});
In data.js, access db from req.app :
module.exports.submit = function(req, res) {
req.app.db.collection('movies').insertOne({ 'title': title, 'year': year, 'imdb': imdb },
function(err, r) {}
)
};

The accepted answer isn't quite correct. You shouldn't attach custom objects to the app object. That's what app.locals is for. Plus, the accepted answer will fail when using Typescript.
app.locals.db = db;
router.get('/foo', (req) => {
req.app.locals.db.insert('bar');
});
Sure, it's longer. But you get the assurance that future updates to ExpressJS will not interfere with your object.

I understand that the answer of #Bertrand is functional, but it is not usually recommended. The reason being that, from a software point of view, you should have a better separation in your software.
app.js
var express = require('express');
var path = require('path')
var MongoClient = require('mongodb').MongoClient;
var bodyParser = require('body-parser');
var app = express();
var routes = require('./routes/index');
var dataRoutes = require('./routes/dataRoutes');
var DB = require('./db.js');
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
DB.Init("mongodb://localhost:27017/m101")
.then(() => {
console.log("Successfully connected to MongoDB.");
app.use('/', routes); // Use normal routes for wesbite
app.use('/data', dataRoutes);
app.get('/favicon.ico', function(req, res) {
res.send(204);
});
var server = app.listen(3000, function() {
var port = server.address().port;
console.log("Express server listening on port %s.", port);
});
})
.catch((e) => {
console.log("Error initializing db");
});
db.js
var _db = null;
module.exports = {
Init: (url) => {
return new Promise((resolve, reject) => {
if (!url)
reject("You should provide a URL");
MongoClient.connect("mongodb://localhost:27017/m101", function(err, db) {
if(err) reject(err);
_db = db;
resolve(); // Or resolve(db) if you wanna return the db object
});
});
},
Submit: (req, res, next) => {
// Whatever goes. You have access to _db here, too!
}
};
in data.js
var DB = require('../db.js');
router.post('/submit', DB.submit);
Finally, even this answer can be improved as you are not usually advised to wait for the DB to connect, otherwise, you are losing the advantage of using ASync procs.
Consider something similar to here in app.js:
Promise.resolve()
.then(() => {
// Whatever DB stuff are
// DB.Init ?
})
.then(() => {
// Someone needs routing?
})
...
.catch((e) => {
console.error("Ther app failed to start");
console.error(e);
});
I understand that in the last sample, you can not instantly query DB as it may not have connected yet, but this is a server, and users are usually expected to wait for your DB to init. However, if you wanna more proof solution, consider implementing something yourself in DB.submit to wait for the connect. Or, you can also use something like mongoose.

Using MongoDB, Express, Node.Js and GridFS-stream for storing video and picture files

I am creating a single page application using JavaScript(JQuery) and need to store large video files which size exceed 16Mb. I found that need to use GridFS supporting large files. As I am the new one to MongoDB I am not sure how to use GridFS. There are some good tutorials on creating applications using Node.js, MongoDB and Express but cant find any describing how to use GridFS with MongoDB (not mongoose), Express and Node.js. I managed to put up stuff for uploading files in the BSON-document size limit of 16MB. This is what I have:
var express = require('express');
var path = require('path');
var bodyParser = require('body-parser');
var mongo = require('mongodb');
var monk = require('monk');
var Grid = require('gridfs-stream');
var db = monk('localhost:27017/elearning');
var gfs = Grid(db, mongo);
var routes = require('./routes/index');
var users = require('./routes/users');
var courses = require('./routes/courses');
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
// Make our db accessible to our router
app.use(function(req,res,next){
req.db = db;
next();
});
app.use('/', routes);
app.use('/users', users);
app.use('/courses', courses);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
// error handlers
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}
// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});
module.exports = app;
And, for example, the courses file is as the following:
var express = require('express');
var router = express.Router();
/* GET courses listing */
router.get('/courselist', function(req, res) {
var db = req.db;
var collection = db.get('courselist');
collection.find({},{},function(e,docs){
res.json(docs);
})
});
/* POST courses data */
router.post('/courselist', function(req, res) {
var db = req.db;
var collection = db.get('courselist');
collection.insert(req.body, function(err, result){
res.send(
(err === null) ? { msg: '' } : { msg: err }
);
});
});
/* Delete courses data */
router.delete('/courselist/:id', function(req, res) {
var db = req.db;
var collection = db.get('courselist');
var userToDelete = req.params.id;
collection.remove({ '_id' : userToDelete }, function(err) {
res.send((err === null) ? { msg: '' } : { msg:'error: ' + err });
});
});
module.exports = router;
I would be extremely grateful for your help, if you could tell how should I edit above files in order to utilize GridFS and be able to get, upload and delete video and picture files from my elearning database.

You can do direct uploading without using mongoose using gridfs-stream as simple as:
var express = require('express'),
mongo = require('mongodb'),
Grid = require('gridfs-stream'),
db = new mongo.Db('node-cheat-db', new mongo.Server("localhost", 27017)),
gfs = Grid(db, mongo),
app = express();
db.open(function (err) {
if (err) return handleError(err);
var gfs = Grid(db, mongo);
console.log('All set! Start uploading :)');
});
//POST http://localhost:3000/file
app.post('/file', function (req, res) {
var writeStream = gfs.createWriteStream({
filename: 'file_name_here'
});
writeStream.on('close', function (file) {
res.send(`File has been uploaded ${file._id}`);
});
req.pipe(writeStream);
});
//GET http://localhost:3000/file/[mongo_id_of_file_here]
app.get('/file/:fileId', function (req, res) {
gfs.createReadStream({
_id: req.params.fileId // or provide filename: 'file_name_here'
}).pipe(res);
});
app.listen(process.env.PORT || 3000);
for complete files and running project:
Clone node-cheat direct_upload_gridfs, run node app followed by npm install express mongodb gridfs-stream.
OR
Follow baby steps at Node-Cheat Direct Upload via GridFS README.md

Very late but I found previous answer outdated. I'm posting this because this might help newbies like me. To run it, please follow previous answers guide. All credit goes to #ZeeshanHassanMemon.
var express = require('express'),
mongoose = require('mongoose'),
Grid = require('gridfs-stream'),
app = express();
Grid.mongo = mongoose.mongo;
conn = mongoose.createConnection('mongodb://localhost/node-cheat-db');
conn.once('open', function () {
var gfs = Grid(conn.db);
app.set('gridfs', gfs);
console.log('all set');
});
//POST http://localhost:3000/file
app.post('/file', function (req, res) {
var gridfs = app.get('gridfs');
var writeStream = gridfs.createWriteStream({
filename: 'file_name_here'
});
writeStream.on('close', function (file) {
res.send(`File has been uploaded ${file._id}`);
});
req.pipe(writeStream);
});
//GET http://localhost:3000/file/[mongo_id_of_file_here]
app.get('/file/:fileId', function (req, res) {
var gridfs = app.get('gridfs');
gridfs.createReadStream({
_id: req.params.fileId // or provide filename: 'file_name_here'
}).pipe(res);
});
app.listen(process.env.PORT || 3000);

router.get('/') on expressjs not working

i can't access to my express application's home page by '/' route pattern. it's working on /index e.g. My express version is 4.6.
I tried app.use('/*', router), but my application is not responding or 503 service temporarily unavailable. It's now working by '/index' pattern and other routes is working correctly. only '/' pattern is not working. :)
Here is my code snippet.
var http = require('http');
var express = require('express');
var app = express();
var router = express.Router();
app.use('/', router);
app.set('view engine', 'ejs');
app.set('views', './views');
app.use(express.static('./public'));
var bodyParser = require("body-parser");
app.use(bodyParser());
var fs = require('fs');
var clientSessions = require("client-sessions");
var form = require('express-form');
var field = form.field;
var sha1 = require('sha1');
var mysql = require('mysql');
var connection = mysql.createConnection({
host: process.env.OPENSHIFT_MYSQL_DB_HOST,
port: process.env.OPENSHIFT_MYSQL_DB_PORT,
user: process.env.OPENSHIFT_MYSQL_DB_USERNAME,
password: process.env.OPENSHIFT_MYSQL_DB_PASSWORD,
database: process.env.OPENSHIFT_GEAR_NAME
});
var multer = require('multer');
var done = false;
app.use(clientSessions({
secret: 'xxxxx'
}));
app.use(function(req, res) {
res.status(400);
res.render('pages/404');
});
// Handle 500
app.use(function(error, req, res, next) {
res.status(500);
res.render('pages/500');
});
//---
app.use(multer({
dest: 'public/uploads/',
rename: function(fieldname, filename) {
return filename + Date.now();
},
onFileUploadStart: function(file) {
console.log(file.originalname + ' is starting ...')
},
onFileUploadComplete: function(file) {
console.log(file.fieldname + ' uploaded to ' + file.path)
done = true;
}
}));
//// --------------- start app routes --------------//
// ----- GET -----
router.get('/', function() { // THIS PATTERN IS NOT WORKING
console.log('hello world'); // this line is not working
connection.query(strQuery, function(err, rows) {
// res.render('pages/index');
});
});

Because you didn't handle "/", here is updated code
var router = express.Router();
app.use('/*', router);
router.get('/', function(req, res) {
res.send('welcome home');
}
router.get('/index', function(req, res) {
res.send('welcome index');
}

You are forgetting '*' in second line
app.use('/*', router);

Do you forget to make redirection?
router.get("/", function (req, res) {
res.redirect("/index");
});