如何在不使用框架的情况下通过Node.js将数据从MongoDB显示到前端

Question

I am new to Node.js and programming in general. This is my first server side language and I need your help. I do have html/css/javascript experience. I also know how to serve up html pages via NodeJS using FileSystem and the request.url stream.

*Question:* How do you query and display data from Mongo DB into an html page without using Express or any other framework? Pure Node.JS /Javascript**

I rather not use Express because I am trying to master Node.JS first.

I tried studying PHP's way of doing it, and found their process to to be like this :

Connect to database:

$con=mysqli_connect("example.com","peter","abc123","my_db");

Query Database:

$result = mysql_query("SELECT * FROM names");

Display Results :

<?php echo $result; ?>

How does Node.js connect / query / and display from database to front end? without using frameworks like EXPRESS

Answer 1

To query mongo with node you are most definetly going to need some sort of node-module such as node-mongo-db-native ( https://github.com/mongodb/node-mongodb-native ). You can't do it with just node core...

Here is an example of querying a mongodb using node-mongo-db-native module docs...

var MongoClient = require('mongodb').MongoClient
    , format = require('util').format;

  MongoClient.connect('mongodb://127.0.0.1:27017/test', function(err, db) {
    if(err) throw err;

    var collection = db.collection('test_insert');
    collection.insert({a:2}, function(err, docs) {

      collection.count(function(err, count) {
        console.log(format("count = %s", count));
      });

      // Locate all the entries using find
      collection.find().toArray(function(err, results) {
        console.dir(results);
        // Let's close the db
        db.close();
      });
    });
  })

Answer 2

Try this example, it contains one route ( http://localhost:3000/test ) which you can request from your frontend and it will return json data taken from the mongodb using mongoose.

Test.js

var express = require("express"),
    app = express(),
    bodyparser = require("body-parser"),
    mongoose = require("mongoose");

const router = express.Router();

app.use(bodyparser.json());

mongoose.connect('mongodb://localhost:27017/test');

const connection = mongoose.connection;

connection.once('open', () => {
    console.log('MongoDB connected successfully');
})

var schema = new mongoose.Schema({
    name: String,
    value: String
})

var data=mongoose.model("testdata", schema);

router.route('/test').get((req, res) => {
    data.find((err, testdata) => {
        if (err)
            console.log(err)
        else
            res.json(testdata);

    })
})


    app.use('/', router);



    app.listen(3000, function () {
        console.log('server started on port 3000');
    });

Answer 3

here is my code which I have run in my localhost, and it is working fine.

Code

const http = require('http');
const port = 8080;
const hostname = 'localhost';

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/testDB', {
   useCreateIndex: true,
   useNewUrlParser: true
});

var schema = new mongoose.Schema({
   firstName: String,
   lastName: String
})

var userSchema = mongoose.model("user", schema);

http.createServer((req, res) => {
   userSchema.find().then((result, err) => {
       res.writeHead(200, { 'Content-Type': 'application/json' });
       res.end(JSON.stringify({status: 200, message: 'data retrive 
           successfully' data : result}));
  })
}).listen(port, () => {
   console.log(`your server are listing http://${hostname}:${port}`);
})

I hope it will help you, To create a server without using the express framework in nodeJS.