Cree una API de Node.js en menos de 30 minutos

Cree una API de Node.js en menos de 30 minutos

Node.js puede resultar intimidante para los principiantes. Pero su estructura flexible y la falta de pautas estrictas lo hacen parecer más complicado de lo que es.

Este tutorial es una guía rápida y sencilla para Node.js, el marco Express y MongoDB, que se centra en las rutas REST fundamentales y la interacción básica con la base de datos. Construirá una plantilla de API simple que luego se puede usar como base para cualquier aplicación.

Para quién es este tutorial : debe tener un conocimiento básico de las API REST y las operaciones CRUD, además de conocimientos básicos de JavaScript. Utilizo ES6 (principalmente funciones de flecha de grasa), pero nada demasiado complejo.

Para este tutorial, creará el esqueleto de un back-end para una aplicación para tomar notas: piense en Google Keep. Desea poder realizar las cuatro acciones CRUD en sus notas: crear, leer, actualizar y eliminar.

Configuración

Si no tiene Node instalado, consulte aquí.

En un nuevo directorio, ejecute npm init y siga las instrucciones, dando a su aplicación el nombre de 'notable' (o cualquier otra cosa que desee).

npm init

Una vez hecho esto, debería tener un package.json listo para ir a su directorio. Esto significa que puede comenzar a instalar las dependencias que necesita para su proyecto.

Utilizará Express como su marco, MongoDB como la base de datos y un paquete llamado body-parser para ayudar a lidiar con las solicitudes JSON.

npm install --save express [email protected] body-parser

También recomiendo encarecidamente instalar Nodemon como dependencia de desarrollo. Es un pequeño paquete simple que reinicia automáticamente su servidor cuando los archivos cambian.

Si tu corres:

npm install --save-dev nodemon

Luego puede agregar el siguiente script a package.json :

// package.json
 "scripts": { "dev": "nodemon server.js" },

Su package.json completo debería verse así:

// package.json
{ "name": "notable", "version": "1.0.0", "description": "", "main": "server.js", "scripts": { "dev": "nodemon server.js" }, "author": "", "license": "ISC", "dependencies": { "body-parser": "^1.15.2", "express": "^4.14.0", "mongodb": "^2.2.16" }, "devDependencies": { "nodemon": "^1.11.0" }}

Ahora puede crear su archivo server.jsy comience a construir su API.

Nuestro servidor

Comencemos solicitando todas sus dependencias en server.js.

// server.js
const express = require('express');const MongoClient = require('mongodb').MongoClient;const bodyParser = require('body-parser');
const app = express();

Vas a utilizar MongoClient para interactuar con tu base de datos. Tenga en cuenta que también inicializa su aplicación como una instancia de Express, su marco.

Lo último que debe hacer para que su servidor esté en funcionamiento es decirle a su aplicación que comience a escuchar solicitudes HTTP.

Puede especificar un puerto e iniciar la escucha así:

// server.js
const port = 8000;
app.listen(port, () => { console.log('We are live on ' + port);});

Ahora, si ejecuta npm run dev (o node server.js si no instaló Nodemon), debería ver 'Estamos en vivo en el puerto 8000' en la terminal.

Su servidor está activo. Pero no hace mucho. O cualquier cosa, de verdad.

Arreglemos eso.

Rutas CRUDdy

Para este ejemplo, desea construir 4 rutas; para CREAR una nota, para LEER sus notas, para ACTUALIZAR una nota y para BORRAR una nota.

Esto le dará una buena idea de cómo estructurar casi cualquier ruta básica con Node.

Sin embargo, para probar su API, debe imitar a un cliente que realiza solicitudes. Para hacerlo, usará una gran aplicación llamada Postman. Le permite realizar solicitudes HTTP simples con cuerpos y parámetros personalizados.

Instale Postman y comencemos a configurar sus rutas.

Súper organizado

La mayoría de los tutoriales de Node.js (y muchas aplicaciones reales) colocan todas sus rutas en un gran archivo route.js . Esto me hace sentir un poquito incómodo. Por el contrario, dividir sus archivos en carpetas separadas conduce a una buena legibilidad y hace que las aplicaciones grandes sean más manejables.

No tienes una gran aplicación, pero hagámoslo bien. Cree los siguientes directorios: una carpeta de aplicaciones con una carpeta de rutas dentro, con un index.js y un archivo note_routes.js dentro.

En otras palabras: root> aplicación> rutas> index.js y note_routes.js.

mkdir appcd appmkdir routescd routestouch index.jstouch note_routes.js

Estos directorios pueden parecer excesivos para su pequeña aplicación simple, pero siempre es bueno comenzar con las mejores prácticas.

Tu primera ruta

Comencemos con la C en CRUD- create. ¿Cómo crearías una nota?

Well, before you do that, you have to build a bit more infrastructure. In Express, routes are wrapped in a function, which takes the Express instance and a database as arguments.

Like this:

// routes/note_routes.js
module.exports = function(app, db) {
};

You can then export this function through your index.js:

// routes/index.js
const noteRoutes = require('./note_routes');
module.exports = function(app, db) { noteRoutes(app, db); // Other route groups could go here, in the future};

Then import it for use in server.js:

// server.js
const express = require('express');const MongoClient = require('mongodb').MongoClient;const bodyParser = require('body-parser');
const app = express();
const port = 8000;
require('./app/routes')(app, {});app.listen(port, () => { console.log('We are live on ' + port);});

Note that since you don’t have a database yet set up, you’re just passing in an empty object.

Okay, now you can make your CREATE route.

The syntax is simple:

// note_routes.js
module.exports = function(app, db) { app.post('/notes', (req, res) => { // You'll create your note here. res.send('Hello') });};

When the app receives a post request to the ‘/notes’ path, it will execute the code inside the callback- passing in a request object (which contains the parameters or JSON of the request) and a response object (used to reply).

You can test this by using Postman to send a POST request to localhost:8000/notes.

Nice! You created your first real route.

Next step is to add some parameters to your request and process them in your API and, finally, add in your database.

Request Parameters

In Postman, go to the Body tab and add some key-value pairs, after selecting the x-www-form-urlencoded radio button.

This will add encoded form data to your request, which you’ll be able to process with your API.

Now in your note_routes.js, let’s just log out the body.

// note_routes.js
module.exports = function(app, db) { app.post('/notes', (req, res) => { console.log(req.body) res.send('Hello') });};

Try sending the Postman request and you’ll see… undefined.

Unfortunately, Express can’t process URL encoded forms on its own. But you did install that body-parser package…

// server.
const express = require('express');const MongoClient = require('mongodb').MongoClient;const bodyParser = require('body-parser');
const app = express();
const port = 8000;
app.use(bodyParser.urlencoded({ extended: true }));
require('./app/routes')(app, {});app.listen(port, () => { console.log('We are live on ' + port);});

Now you should see the body as an object in the terminal.

{ title: 'My Note Title', body: 'What a great note.' }

Last step to your preliminary route: set up the database, and then add your data in.

The easiest way to set up a Mongo database is through mLab: it’s free for the smallest size, and quite fast to setup.

Once you create an account and a MongoDB deployment, add a user to the database with a username and password:

then grab the URL here (the second one):

And in a directory config in the root of your project, create a db.js file.

mkdir config cd configtouch db.js

Inside, add the URL:

module.exports = { url : YOUR URL HERE};

Don’t forget to add your username and password (the ones from the database user, not your mLab account) into the URL. (If you’re committing this project to Github, be sure to include a .gitignore file like so, so you don’t share your password with everyone.)

Now in your server.js, you can use the MongoClient to connect to your DB, and use this to wrap your app setup:

// server.js
const express = require('express');const MongoClient = require('mongodb').MongoClient;const bodyParser = require('body-parser');const db = require('./config/db');
const app = express();
const port = 8000;
app.use(bodyParser.urlencoded({ extended: true }));
MongoClient.connect(db.url, (err, database) => { if (err) return console.log(err) require('./app/routes')(app, database);
 app.listen(port, () => { console.log('We are live on ' + port); }); })

If you’re using the latest version of the MongoDB (3.0+), modify it like so:

// server.js
const express = require('express');const MongoClient = require('mongodb').MongoClient;const bodyParser = require('body-parser');const db = require('./config/db');
const app = express();
const port = 8000;
app.use(bodyParser.urlencoded({ extended: true }));
MongoClient.connect(db.url, (err, database) => { if (err) return console.log(err) // Make sure you add the database name and not the collection name const database = database.db("note-api") require('./app/routes')(app, database);
 app.listen(port, () => { console.log('We are live on ' + port); }); })

(Thanks to Alex Stroulger for the fix for 3.0)

That’s the last of your infrastructure setup! It’s all route-building from here.

Adding to your Database

MongoDB stores data in collections- which are exactly how they sound. In your case, you want to store your notes in a collection called — you guessed it — notes.

Since you pass in your database as the db argument in your routes, you can then access it like so:

db.collection('notes')

Creating a note is as simple as calling insert on your collection:

const note = { text: req.body.body, title: req.body.title} db.collection('notes').insert(note, (err, results) => {}

Once the insert is complete (or has failed for whatever reason), you want to either send back an error or send back the newly created note object. Here’s the full note_routes.js:

// note_routes.js
module.exports = function(app, db) { const collection = app.post('/notes', (req, res) => { const note = { text: req.body.body, title: req.body.title }; db.collection('notes').insert(note, (err, result) => { if (err) { res.send({ 'error': 'An error has occurred' }); } else { res.send(result.ops[0]); } }); });};

Try it out! Send an x-www-form-urlencoded POST request with Postman, with a title and body set under the Body tab.

The response should look like this:

If you log into mLab, you should also see the created note in the database.

Your READ Route

Now you can pick up the pace a bit.

Say you wanted to get back the note you just created, by navigating to localhost:8000/notes/{the id}. In this case, that would be localhost:8000/notes/585182bd42ac5b07a9755ea3.

(If you don’t have the ID for one of your notes, you can check on mLab or just create a new one).

Here’s what this would look like in note_routes.js:

// note_routes.js
module.exports = function(app, db) { app.get('/notes/:id', (req, res) => { });
 app.post('/notes', (req, res) => { const note = { text: req.body.body, title: req.body.title }; db.collection('notes').insert(note, (err, result) => { if (err) { res.send({ 'error': 'An error has occurred' }); } else { res.send(result.ops[0]); } }); });};

Just like before, you’re going to call a method on your database collection of notes. Here, it’s the aptly named findOne.

// note_routes.js
module.exports = function(app, db) { app.get('/notes/:id', (req, res) => { const details = { '_id':  }; db.collection('notes').findOne(details, (err, item) => { if (err) { res.send({'error':'An error has occurred'}); } else { res.send(item); } }); });
app.post('/notes', (req, res) => { const note = { text: req.body.body, title: req.body.title }; db.collection('notes').insert(note, (err, result) => { if (err) { res.send({ 'error': 'An error has occurred' }); } else { res.send(result.ops[0]); } }); });};

You can grab the id from the URL parameters via req.params.id. However, if you try to just plop in the string into the above, it won’t work.

MongoDB requires not just an ID as a string, but as an ID object or, as they call it, an ObjectID.

Don’t worry, it’s an easy fix. Here’s the full code:

// note_routes.js
var ObjectID = require('mongodb').ObjectID;
module.exports = function(app, db) { app.get('/notes/:id', (req, res) => { const id = req.params.id; const details = { '_id': new ObjectID(id) }; db.collection('notes').findOne(details, (err, item) => { if (err) { res.send({'error':'An error has occurred'}); } else { res.send(item); } }); });
app.post('/notes', (req, res) => { const note = { text: req.body.body, title: req.body.title }; db.collection('notes').insert(note, (err, result) => { if (err) { res.send({ 'error': 'An error has occurred' }); } else { res.send(result.ops[0]); } }); });};

Try it out with one of your note ID’s, and it should look like this:

Your DELETE Route

Deleting an object is actually pretty much the same as finding an object. You just use the remove function instead of the findOne. Here’s the full code. I’ve highlighted what’s different from your GET:

// note_routes.js
// ...
 app.delete('/notes/:id', (req, res) => { const id = req.params.id; const details = { '_id': new ObjectID(id) }; db.collection('notes').remove(details, (err, item) => { if (err) { res.send({'error':'An error has occurred'}); } else { res.send('Note ' + id + ' deleted!'); } }); });
// ...

Your UPDATE Route

Last one! The PUT is basically a hybrid between READ and CREATE. You find the object, then update it accordingly. If you deleted your only note, time to make another one!

The code:

// note_routes.js
// ...
 app.put('/notes/:id', (req, res) => { const id = req.params.id; const details = { '_id': new ObjectID(id) }; const note = { text: req.body.body, title: req.body.title }; db.collection('notes').update(details, note, (err, result) => { if (err) { res.send({'error':'An error has occurred'}); } else { res.send(note); } }); });
// ...

Now you can update any of your notes, like so:

Note the imperfection with this code- if you fail to supply a body or title, the PUT request will nullify those fields on the note in the database.

You could easily add some conditional logic to update the fields only if they’re present in the request- I left that out just to keep it simple.

API Complete

That’s it! You have a working Node API with each of the four major CRUD operations.

The goal of this tutorial was to give you a degree of familiarity with Express, Node, and MongoDB — you can use your simple app as a launching pad for more complex projects.

In the future I’ll be writing tutorials to create more simple API’s in different languages and frameworks. Hit the follow button if you’re interested!

If this tutorial was any help to you, please hit the green heart below- it means a lot. Feel free to also leave me a comment with any feedback or questions.

Thanks for reading!