How to create a simple retrieve API after the connection has been done? - mongodb

Question

I am very new to MongoDB and Nodejs and I would like to know how to create a very simple find all the records from a collection.
What I have done so far and it is listening to port 5000 in the console log:
const express = require('express')
const BodyParser = require("body-parser");
const {MongoClient} = require('mongodb')
const port = 5000;
const app = express()
app.use(BodyParser.json());
app.use(BodyParser.urlencoded({ extended: true }));
var db;
const uri = "mongodb+srv://user1:mypassword#cluster0.2sgiu.mongodb.net/ecommerce?retryWrites=true&w=majority";
app.listen(port,() => {
MongoClient.connect(uri, { useNewUrlParser: true, useUnifiedTopology: true}, (err, database) => {
if (err) {
console.log("Error occurred connecting to MongoDB...")
}
console.log(`Listening to part ${port}...`)
});
})
How do I proceed from here to create an API to retrieve all records from a Books collection after the connection has been done? Thanks

Answer 1

You should first save the database object that is returned to you by the callback function of connect (let's called that db).
Then, you can use that object to access your collections like "Books" in this example:
db.Books
To get all the documents inside a collection you can use the find method with an empty object as the argument.
const books = db.Books.find({});
If you want to tie MongoDB queries to your Express app, you should a create routes in which, you can respond the request with data that you fetched. Considering that this data is going to be publicly available.
app.get('/books', (req, res) => {
const books = db.Books.find({});
res.status(200).send({ books });
});
You can now make a GET request to localhost:5000/books and it should respond to you back with the contents of the Books collection. Either use your browser or curl to make the request.
$ curl localhost:5000/books