I tried searching on the web and found no obvious code samples of how reuse the mongodb.connection object. This is what I have currently and would anyone please verify if this is okay.
var app = express();
var mongodb = require('mongodb').MongoClient, format = require('util').format;
var db = null;
app.get('/api/v1/put/:var1/:var2', function(req, res){
collection = db.collection('collection');
/** .. logic ... **/
});
mongodb.connect('mongodb://127.0.0.1:27017/mydb', function(err, mdb){
db = mdb;
app.listen(8000);
});
Your approach will have problem that once application runs it will register express route. If there is idling connections to your web server, then they will be processed ASAP, that will lead to db is undefined.
In order to prevent this, I would recommend to register express routing only after database is connected.
As well you can cache collections instead of getting them on each request.
this is just to refactor my question's code to reflect Maksims' suggestion
var app = express();
var mongodb = require('mongodb').MongoClient, format = require('util').format;
mongodb.connect('mongodb://127.0.0.1:27017/mydb', function(err, db){
collection = db.collection('collection');
app.get('/api/v1/put/:var1/:var2', function(req, res){
/** .. logic ... **/
});
app.listen(8000);
});
Related
I'm a total beginner at this and am using a tutorial to learn the basics of the MEAN stack. I am trying to return the documnents in my database to a web page but am instead receiving an empty array.
I have created a cluster on Mongodb Atlas called mytasklist. Inside here I created a database called mytasklistdb. Inside this I have a table (object) called mytasklistdb.mytasklisttutorial. My understanding of this is limited and so maybe I'm making a huge error somewhere here. I have experience of SQL but not Mongo and so the whole 'clusters' and 'collections' thing is new to me.
Anyway my code is as follows. I took the string for the database connection from the Mongo connection tab.
var express = require('express');
var router = express.Router();
var mongojs = require('mongojs');
var db = mongojs('mongodb+srv://myusername:mypassword#mytasklist-qx0ka.mongodb.net/test?retryWrites=true&w=majority', ['mytasklisttutorial']);
router.get('/tasks', function(req, res, next){
db.mytasklistdb.find(function(err, tasks){
if(err){
res.send(err);
}
res.json(tasks);
});
});
module.exports = router;
My database objects look like this:
_id:5db5f1f31c9d440000c3e7fe
title:"Walk the dog" - this is a string
isDone:false - this is boolean
I'm just getting an empty array but in the tutorial the guy is getting these 'documents'. What am I doing wrong?
EDIT: I realised that the 'tasks' part of the tutorial example was relating to a database called 'tasks'. Mine is called 'mytasklistdb'. I therefore changed this. I also added a parameter with the name of my collection to the line passed in to mongojs.
I have changed my code above to reflect this
The solution was to replace 'task' and 'test' with the name of my db. As follows:
var express = require('express');
var router = express.Router();
var mongojs = require('mongojs');
var db = mongojs('mongodb+srv://James:Noentry1#mytasklist-qx0ka.mongodb.net/mytasklistdb?retryWrites=true&w=majority', ['mytasklisttutorial']);
router.get('/tasks', function(req, res, next){
db.mytasklisttutorial.find(function(err, tasks){
if(err){
res.send(err);
}
res.json(tasks);
});
});
module.exports = router;
My guess is that you are not passing your query, just the callback in the find() method, probably you need to do something like this:
db.tasks.find({},function(err, tasks){
if(err){
res.send(err);
}
res.json(tasks);
});
I have a MongoDb server hosted on Azure. I'm now building a Node.js API meant to retrieve data from a table on one of the databases (i.e. table: Word; database: MyDatabase). I've built the API following this tutorial, but I'm unable to successfully retrieve any data from it...
I know the server is up and running and also reachable since I can tcp-connect to it through:
psping [Azure's Public IP]:27017
Now, I have an node.js api with the following code:
1) app/server.js
var express = require('express'); // call express
var app = express(); // define our app using express
var bodyParser = require('body-parser');
var mongoose = require('mongoose');
mongoose.connect('mongodb://[Azure's public IP]:27017/MyDatabase');
var Word = require('./models/word');
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
var port = process.env.PORT || 8080; // set our port
// ROUTES FOR API
var router = express.Router(); // get an instance of the express Router
// middleware to use for all requests
router.use(function(req, res, next) {
// do logging
console.log('Something is happening.');
next();
});
router.get('/', function(req, res) {
res.json({ message: 'hooray! welcome to our api!' });
});
router.route('/words')
.get(function(req, res) {
Word.find(function(err, words) {
if (err)
res.send(err);
res.json(words);
});
});
// more routes for our API will happen here
// REGISTER OUR ROUTES -------------------------------
// all of our routes will be prefixed with /api
app.use('/api', router);
// START THE SERVER
// =============================================================================
app.listen(port);
console.log('Magic happens on port ' + port);
I've also written a model for my only table within the database, which has 3 columns: the auto-generated ObjectId, Spanish, French (meant to have words in both languages to make it work as a translator). The models looks like this: 2) app/models/word.js
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var WordSchema = new Schema({
spanish: String,
french: String
})
var Word = mongoose.model('Word',WordSchema);
module.exports = Word;
Now, I go to postman and GET on the following: http://localhost:8080/api/words; which returns [].
On MongoDb logs I see the following:
2016-08-05T03:16:26.520+0000 I NETWORK [conn60] end connection [Some IP]:[Some port] (1 connections now open)
2016-08-05T03:31:11.878+0000 I NETWORK [initandlisten] connection accepted from [Some IP]:[Some port] #61 (1 connection now open)
As you mentioned in your comment that the documents were retrieved from db.word.find() I think I found the problem. You need to put documents into collection named words, instead of word.
Mongoose will use the plural version of your model name. See http://mongoosejs.com/docs/models.html for more information.
I think you are missing {} when doing find.
router.route('/words')
.get(function(req, res) {
Word.find({}, //Added here.
function(err, words) {
if (err)
res.send(err);
console.log(words)
res.json(words);
});
});
Hope this will help.
EDIT:-
According the document of doc, the find function accept the first parameter as an object and treat it as conditions, but not a callback function.
I'm developing my first Node.js App with Socket.IO and everything is fine but now the app is slowly getting bigger and I'd like to divide the app-code into different files for better maintenance.
For example I'm defining all my mongoose schemas and the routings in the main file. Underneath are all the functions for the socket.IO connection. But now I want to have an extra file for the schemas, an extra file for routing and one for the functions.
Of course, I'm aware of the possibility to write my own module or load a file with require. That just does not make sense for me, because I can't work with the vars like app, io or db without making them global. And if I pass them to a function in my module, I can't change them. What am I missing? I'd like to see an example how this is done in practice without using global vars..
It sounds like you have a highly coupled application; it's difficult for you to split out your code into modules because pieces of the application that should not depend on each other do. Looking into the principles of OO design may help out here.
For example, if you were to split your dataabse logic out of the main application, you should be able to do so, as the database logic should not depend on app or io--it should be able to work on its own, and you require it into other pieces of your application to use it.
Here's a fairly basic example--it's more pseudocode than actual code, as the point is to demonstrate modularity by example, not to write a working application. It's also only one of many, many ways you may decide to structure your application.
// =============================
// db.js
var mongoose = require('mongoose');
mongoose.connect(/* ... */);
module.exports = {
User: require('./models/user');
OtherModel: require('./models/other_model');
};
// =============================
// models/user.js (similar for models/other_model.js)
var mongoose = require('mongoose');
var User = new mongoose.Schema({ /* ... */ });
module.exports = mongoose.model('User', User);
// =============================
// routes.js
var db = require('./db');
var User = db.User;
var OtherModel = db.OtherModel;
// This module exports a function, which we call call with
// our Express application and Socket.IO server as arguments
// so that we can access them if we need them.
module.exports = function(app, io) {
app.get('/', function(req, res) {
// home page logic ...
});
app.post('/users/:id', function(req, res) {
User.create(/* ... */);
});
};
// =============================
// realtime.js
var db = require('./db');
var OtherModel = db.OtherModel;
module.exports = function(io) {
io.sockets.on('connection', function(socket) {
socket.on('someEvent', function() {
OtherModel.find(/* ... */);
});
});
};
// =============================
// application.js
var express = require('express');
var sio = require('socket.io');
var routes = require('./routes');
var realtime = require('./realtime');
var app = express();
var server = http.createServer(app);
var io = sio.listen(server);
// all your app.use() and app.configure() here...
// Load in the routes by calling the function we
// exported in routes.js
routes(app, io);
// Similarly with our realtime module.
realtime(io);
server.listen(8080);
This was all written off the top of my head with minimal checking of the documentation for various APIs, but I hope it plants the seeds of how you might go about extracting modules from your application.
I am trying to create a login system where an admin can log in and look at data that is not available to the public. Right now I'm just trying to find my admin instance in my database. I have two node files: app.js and account_manager.js
app.js
//creates node app
var express = require('express');
var app = express();
var mongoose = require('mongoose');
var AM = require('./account_manager');
//stuff...
/***************************************
LOGIN
***************************************/
app.post('/login', function(req, res){
AM.manualLogin(req.param('username'), req.param('password'), function(e, o){
if (!o){
res.send(e, 400);
} else{
req.session.user = o;
res.send(o, 200);
}
});
});
account_manger.js is required in app.js and is stored in AM
account_manager.js:
var express = require('express');
var app = express();
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost');
var admin_db = mongoose.connection;
admin_db.on('error', console.error.bind(console, 'connection error: '));
//connection open?
admin_db.once('open', function callback(){
console.log("User Database connection open!\n");
});
var User_Schema = new mongoose.Schema({username: String, password: String});
var Admin = mongoose.model('Admin', User_Schema);
exports.manualLogin = function(user, pass, callback)
{
admin_db.find({username: user},function(err,docs){ //error is here
if(docs){
var x = 0;
var flag = false;
while(docs[x]){ //goes through all the admins
if (docs[x].param("username") == user){ //if it's a match
callback(null, docs);
flag = true;
break;
}
x+=1;
}
if (flag == false){
callback('invalid-password/username');
}
}
});
}
I get a TypeError that says:
Object #<NativeConnection> has no method 'find'
what's my problem?
I'm still quite new to node.js myself, but I'll try and answer anyway.
It looks like you've properly built your connection to mongodb through mongoose, but you have not created a schema. While mongodb doesn't have schemas, mongoose does.
What you'll need to do is create a schema (UserSchema) that matches the construction of a user document in your users collection, then create an instance of that schema (User) which is now your model, then call .find on that model.
The Mongoose Quick Start guide goes through this process:
http://mongoosejs.com/docs/index.html
EDIT after update:
You are currently calling admin_db.find. This does not exist. This is the error you are getting.
You need to change that to Admin.find. You also need to understand what the difference is.
EDIT once more:
You're not properly using the admin_db.once callback.
I suggest you go back and reread the Mongoose Quick Start guide I linked. It's quite short and goes through all of this.
I see you're rolling your own system here, but I thought I'd share a link to Drywall in case you could gain some inspiration or knowledge from it.
Drywall - A website and user system for Node.js: http://jedireza.github.io/drywall/
I hope this is helpful. Feel free to open issues in GitHub if you run into any road blocks.
I'm developing my first Node.js App with Socket.IO and everything is fine but now the app is slowly getting bigger and I'd like to divide the app-code into different files for better maintenance.
For example I'm defining all my mongoose schemas and the routings in the main file. Underneath are all the functions for the socket.IO connection. But now I want to have an extra file for the schemas, an extra file for routing and one for the functions.
Of course, I'm aware of the possibility to write my own module or load a file with require. That just does not make sense for me, because I can't work with the vars like app, io or db without making them global. And if I pass them to a function in my module, I can't change them. What am I missing? I'd like to see an example how this is done in practice without using global vars..
It sounds like you have a highly coupled application; it's difficult for you to split out your code into modules because pieces of the application that should not depend on each other do. Looking into the principles of OO design may help out here.
For example, if you were to split your dataabse logic out of the main application, you should be able to do so, as the database logic should not depend on app or io--it should be able to work on its own, and you require it into other pieces of your application to use it.
Here's a fairly basic example--it's more pseudocode than actual code, as the point is to demonstrate modularity by example, not to write a working application. It's also only one of many, many ways you may decide to structure your application.
// =============================
// db.js
var mongoose = require('mongoose');
mongoose.connect(/* ... */);
module.exports = {
User: require('./models/user');
OtherModel: require('./models/other_model');
};
// =============================
// models/user.js (similar for models/other_model.js)
var mongoose = require('mongoose');
var User = new mongoose.Schema({ /* ... */ });
module.exports = mongoose.model('User', User);
// =============================
// routes.js
var db = require('./db');
var User = db.User;
var OtherModel = db.OtherModel;
// This module exports a function, which we call call with
// our Express application and Socket.IO server as arguments
// so that we can access them if we need them.
module.exports = function(app, io) {
app.get('/', function(req, res) {
// home page logic ...
});
app.post('/users/:id', function(req, res) {
User.create(/* ... */);
});
};
// =============================
// realtime.js
var db = require('./db');
var OtherModel = db.OtherModel;
module.exports = function(io) {
io.sockets.on('connection', function(socket) {
socket.on('someEvent', function() {
OtherModel.find(/* ... */);
});
});
};
// =============================
// application.js
var express = require('express');
var sio = require('socket.io');
var routes = require('./routes');
var realtime = require('./realtime');
var app = express();
var server = http.createServer(app);
var io = sio.listen(server);
// all your app.use() and app.configure() here...
// Load in the routes by calling the function we
// exported in routes.js
routes(app, io);
// Similarly with our realtime module.
realtime(io);
server.listen(8080);
This was all written off the top of my head with minimal checking of the documentation for various APIs, but I hope it plants the seeds of how you might go about extracting modules from your application.