scope integrating mongo in a node/express file - json

Question

I am starting with Mongo db. I want to insert two variables into mongo. So, in the same file
1.- I define the two variables
2.- I create a function that returns a JSON format object with the two variables
3.- I create an app in Express to fill the values of the two variables and send them out as well
4.- I connected to Mongo and insert the JSON object creating a collection and passing in the first argument a call to the function that returns the JSON object with two arguments that are the two variables.
RESULT CHECKING IN THE CONSOLE:
1.- The connection is correct
2.- There is a JSON object inserted but empty
I think I have a problem of scopes.How would it be the right sequence?
// Express files
var express = require('express');
var app = express();
// Mongo files
var mongodb=require("mongodb")
var MongoClient = mongodb.MongoClient;
var MONGODB_URI="mongodb://user:psswd#00000.mlab.com:00000/"
// Variables
var one;
var two;
// JSON object to insert in mongo
var doc=function(one,two){
return{
"one":one,
"two": two
}
}
// App in Express
app.get("new/:which",function(req,res){
one=req.params.which
var randomNum=Math.round(Math.random()*10000)
two=req.headers["x-forwarded-host"]+("/")+randomNum.toString()
res.end(JSON.stringify(doc(one,two)))
})
// Mongo connection and insertion of JSON object
MongoClient.connect(MONGODB_URI,function(err,db){
if (err) {
console.log('Unable to connect to the mongoDB server.
Error:', err);
} else {
console.log('Connection established to', MONGODB_URI);
}
var collection=db.collection("url")
collection.insert(doc(one,two),function(){
if(err) throw err
console.log(JSON.stringify(doc(one,two)))
db.close()
})
})

Answer 1

// Express files
var express = require('express');
var app = express();
//mongoose files
var mongoose = require('mongoose');
mongoose.Promise = require('bluebird');
mongoose.connect('mongodb://user:psswd#00000.mlab.com:00000/'), {
useMongoClient: true,
});
//Define the document schema
var Schema = new mongoose.Schema({
one: {
type: String, //or maybe Number
required: true
},
two: {
type: String,
required: true
},
});
var Model = mongoose.model('model', Schema);
app.get("/new/:which",function(req,res){
one=req.params.which
var randomNum=Math.round(Math.random()*10000)
two=req.headers["x-forwarded-host"]+ ("/")+randomNum.toString();
var new_doc = new Model({
one: one,
two: two
});
new_doc.save(err=>{
err ? res.send(err) : res.send('added!');
});
});
I recommend to use mongoose npm package for working with mongo
You can split the code into modules for more comfortability

Answer 2

I found the answer to the question of the scopes in a freecourse for Node developers in MongoDB University showing how to put all together Mongo University
The sequence is the following:
//Dependencies
var express = require('express');
var app = express();
var mongodb=require("mongodb")
var MongoClient = mongodb.MongoClient;
var MONGODB_URI
="mongodb://<user>:<psswd>#000000.mlab.com:41358"
// Connection to mongo
MongoClient.connect(MONGODB_URI,function(err,db){
app.use("/new/:which",function(req,res){
var one=req.params.which
var two=req.headers["x-forwarded-host"]+"/"+randomNum
// Insertion of documents
db.collection("url").insertOne({"one":one,
"two":two})
res.send({"one":one,"two":two})
})
var listener = app.listen(8000)
}
So, the app need to be within the scope of the mongo connection and the collection methods within the scope of the app.
At the same level that the app will be the port.
The documents inserted in the database and the result send it out to the client as well.