In the post, Grokiz guides how to change _id to id in returned response when using Mongoose ODM with Node.js/Express RestAPIs application example.
Related posts:
– Crud RestAPIs with NodeJS/Express, MongoDB using Mongoose
Contents
Technologies
– Node.js/Express
– Mongoose ODM
– MongoDB
Goal
– Mongoose ODM uses “_id” attribute to identiy an Object’s id:
How to change _id to id in RestAPI’s returned response?
-> In Mongoose model, we can implement a method transform to resolve it:
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const mongoose = require('mongoose'); var Schema = mongoose.Schema; var bookSchema = new Schema({ title: String, author: String, description: String, published: String }); bookSchema.method('transform', function() { var obj = this.toObject(); //Rename fields obj.id = obj._id; delete obj._id; return obj; }); module.exports = mongoose.model('Book', bookSchema); |
-> Result:
Practice
Project structure:
Setting up Nodejs/Express project
Init package.json by cmd:
npm init
Install express, mongoose:
$npm install express mongoose --save
-> now package.json file:
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{ "name": "nodejs-restapis-mongoose", "version": "1.0.0", "description": "Nodejs-RestAPI-Mongoose", "main": "server.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "keywords": [ "Nodejs", "RestAPI", "Mongoose" ], "author": "grokonez.com", "license": "ISC", "dependencies": { "express": "^4.16.4", "mongoose": "^5.4.2" } } |
Setting up Mongoose connection
– ./app/config/mongodb.config.js file:
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module.exports = { url: 'mongodb://localhost:27017/nodejs-demo' } |
Create Mongoose model
– ./app/model/book.model.js file:
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const mongoose = require('mongoose'); var Schema = mongoose.Schema; var bookSchema = new Schema({ title: String, author: String, description: String, published: String }); bookSchema.method('transform', function() { var obj = this.toObject(); //Rename fields obj.id = obj._id; delete obj._id; return obj; }); module.exports = mongoose.model('Book', bookSchema); |
Express RestAPIs
Route
Define Book’s routes in ./app/route/book.route.js file:
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module.exports = function(app) { const books = require('../controller/book.controller.js'); // Retrieve all Books app.get('/api/books', books.findAll); // Retrieve a single Book by Id app.get('/api/books/:bookId', books.findOne); } |
Controller
Implement Book’s controller in ./app/controller/book.controller.js file:
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const Book = require('../model/book.model.js'); // FETCH all Books exports.findAll = (req, res) => { Book.find() .then(books => { let returnedBooks = []; for (let i = 0; i < books.length; i++) { returnedBooks.push(books[i].transform()); } res.send(returnedBooks); }).catch(err => { res.status(500).send({ message: err.message }); }); }; // FIND a Book exports.findOne = (req, res) => { Book.findById(req.params.bookId) .then(book => { if(!book) { return res.status(404).send({ message: "Book not found with id " + req.params.bookId }); } res.send(book.transform()); }).catch(err => { if(err.kind === 'ObjectId') { return res.status(404).send({ message: "Book not found with id " + req.params.bookId }); } return res.status(500).send({ message: "Error retrieving Book with id " + req.params.bookId }); }); }; |
Server.js
– server.js file:
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var express = require('express'); var app = express(); var bodyParser = require('body-parser'); app.use(bodyParser.json()) // Configuring the database const dbConfig = require('./app/config/mongodb.config.js'); const mongoose = require('mongoose'); const Book = require('./app/model/book.model.js'); mongoose.Promise = global.Promise; // Connecting to the database mongoose.connect(dbConfig.url) .then(() => { console.log("Successfully connected to MongoDB."); initial(); }).catch(err => { console.log('Could not connect to MongoDB.'); process.exit(); }); require('./app/route/book.route.js')(app); // Create a Server var server = app.listen(8080, function () { var host = server.address().address var port = server.address().port console.log("App listening at http://%s:%s", host, port) }) function initial(){ Book.create({ title: "Origin", author: "Dan Brown", description: "Origin thrusts Robert Langdon into the dangerous ntersectio of humankind's two most enduring questions", published: "2017" }); Book.create({ title: "Happy Potter and the Deathly Hallows", author: "J.K. Rowling", description: "The seventh and final novel of the Harry Potter series.", published: "2007" }); Book.create({ title: "The 100-Year-Old Man Who Climbed Out the Window and Disappeared", author: "Jonas Jonasson", description: "", published: "2009" }); } |
Run & Check Results
– Run MongoDB mongod.exe.
– Run Nodejs application: npm start
-> Make requests:
