We will build Rest Apis that can create, retrieve, update, delete and find Tutorials by title.
First, we start with an Express web server. Next, we add configuration for MongoDB database, create Tutorial model with Mongoose, write the controller. Then we define routes for handling all CRUD operations (including custom finder).
The following table shows overview of the Rest APIs that will be exported:
Finally, we’re gonna test the Rest Apis using Postman.
In the root folder, let’s create a new server.js file:
const express = require("express");
const bodyParser = require("body-parser");
const cors = require("cors");
const app = express();
var corsOptions = {
origin: "http://localhost:8081"
};
app.use(cors(corsOptions));
// parse requests of content-type - application/json
app.use(bodyParser.json());
// parse requests of content-type - application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: true }));
// simple route
app.get("/", (req, res) => {
res.json({ message: "Welcome to bezkoder application." });
});
// set port, listen for requests
const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
console.log(`Server is running on port ${PORT}.`);
});
What we do are:
– import express, body-parser and cors modules:
Express is for building the Rest apis
body-parser helps to parse the request and create the req.body object
cors provides Express middleware to enable CORS with various options.
– create an Express app, then add body-parser and cors middlewares using app.use() method. Notice that we set origin: http://localhost:8081.
– define a GET route which is simple for test.
– listen on port 8080 for incoming requests.
Now let’s run the app with command: node server.js.
Open your browser with url http://localhost:8080/, you will see:
Yeah, the first step is done. We’re gonna work with Mongoose in the next section.
Configure MongoDB database & Mongoose
In the app folder, we create a separate config folder for configuration with db.config.js file like this:
This Mongoose Model represents tutorials collection in MongoDB database. These fields will be generated automatically for each Tutorial document: _id, title, description, published, createdAt, updatedAt, __v.
If you use this app with a front-end that needs id field instead of _id, you have to override toJSON method that map default object to a custom object. So the Mongoose model could be modified as following code:
find all Tutorials by title: find({ title: { $regex: new RegExp(title), $options: “i” } })
These functions will be used in our Controller.
Create the Controller
Inside app/controllers folder, let’s create tutorial.controller.js with these CRUD functions:
create
findAll
findOne
update
delete
deleteAll
findAllPublished
const db = require("../models");
const Tutorial = db.tutorials;
// Create and Save a new Tutorial
exports.create = (req, res) => {
};
// Retrieve all Tutorials from the database.
exports.findAll = (req, res) => {
};
// Find a single Tutorial with an id
exports.findOne = (req, res) => {
};
// Update a Tutorial by the id in the request
exports.update = (req, res) => {
};
// Delete a Tutorial with the specified id in the request
exports.delete = (req, res) => {
};
// Delete all Tutorials from the database.
exports.deleteAll = (req, res) => {
};
// Find all published Tutorials
exports.findAllPublished = (req, res) => {
};
Let’s implement these functions.
Create a new object
Create and Save a new Tutorial:
exports.create = (req, res) => {
// Validate request
if (!req.body.title) {
res.status(400).send({ message: "Content can not be empty!" });
return;
}
// Create a Tutorial
const tutorial = new Tutorial({
title: req.body.title,
description: req.body.description,
published: req.body.published ? req.body.published : false
});
// Save Tutorial in the database
tutorial
.save(tutorial)
.then(data => {
res.send(data);
})
.catch(err => {
res.status(500).send({
message:
err.message || "Some error occurred while creating the Tutorial."
});
});
};
Retrieve objects (with condition)
Retrieve all Tutorials/ find by title from the database:
exports.findAll = (req, res) => {
const title = req.query.title;
var condition = title ? { title: { $regex: new RegExp(title), $options: "i" } } : {};
Tutorial.find(condition)
.then(data => {
res.send(data);
})
.catch(err => {
res.status(500).send({
message:
err.message || "Some error occurred while retrieving tutorials."
});
});
};
We use req.query.title to get query string from the Request and consider it as condition for findAll() method.
Retrieve a single object
Find a single Tutorial with an id:
exports.findOne = (req, res) => {
const id = req.params.id;
Tutorial.findById(id)
.then(data => {
if (!data)
res.status(404).send({ message: "Not found Tutorial with id " + id });
else res.send(data);
})
.catch(err => {
res
.status(500)
.send({ message: "Error retrieving Tutorial with id=" + id });
});
};
Update an object
Update a Tutorial identified by the id in the request:
exports.update = (req, res) => {
if (!req.body) {
return res.status(400).send({
message: "Data to update can not be empty!"
});
}
const id = req.params.id;
Tutorial.findByIdAndUpdate(id, req.body, { useFindAndModify: false })
.then(data => {
if (!data) {
res.status(404).send({
message: `Cannot update Tutorial with id=${id}. Maybe Tutorial was not found!`
});
} else res.send({ message: "Tutorial was updated successfully." });
})
.catch(err => {
res.status(500).send({
message: "Error updating Tutorial with id=" + id
});
});
};
Delete an object
Delete a Tutorial with the specified id:
exports.delete = (req, res) => {
const id = req.params.id;
Tutorial.findByIdAndRemove(id)
.then(data => {
if (!data) {
res.status(404).send({
message: `Cannot delete Tutorial with id=${id}. Maybe Tutorial was not found!`
});
} else {
res.send({
message: "Tutorial was deleted successfully!"
});
}
})
.catch(err => {
res.status(500).send({
message: "Could not delete Tutorial with id=" + id
});
});
};
When a client sends request for an endpoint using HTTP request (GET, POST, PUT, DELETE), we need to determine how the server will reponse by setting up the routes.
These are our routes:
/api/tutorials: GET, POST, DELETE
/api/tutorials/:id: GET, PUT, DELETE
/api/tutorials/published: GET
Create a turorial.routes.js inside app/routes folder with content like this:
module.exports = app => {
const tutorials = require("../controllers/tutorial.controller.js");
var router = require("express").Router();
// Create a new Tutorial
router.post("/", tutorials.create);
// Retrieve all Tutorials
router.get("/", tutorials.findAll);
// Retrieve all published Tutorials
router.get("/published", tutorials.findAllPublished);
// Retrieve a single Tutorial with id
router.get("/:id", tutorials.findOne);
// Update a Tutorial with id
router.put("/:id", tutorials.update);
// Delete a Tutorial with id
router.delete("/:id", tutorials.delete);
// Create a new Tutorial
router.delete("/", tutorials.deleteAll);
app.use('/api/tutorials', router);
};
You can see that we use a controller from /controllers/tutorial.controller.js.
We also need to include routes in server.js (right before app.listen()):
...
require("./app/routes/turorial.routes")(app);
// set port, listen for requests
const PORT = ...;
app.listen(...);
Test the APIs
Run our Node.js application with command: node server.js.
Using Postman, we’re gonna test all the Apis above.
Create a new Tutorial using POST /tutorials Api
After creating some new Tutorials, you can check MongoDb collection:
Retrieve a single Tutorial by id using GET /tutorials/:id Api
Update a Tutorial using PUT /tutorials/:id Api
Check tutorials collection after some documents were updated:
Find all Tutorials which title contains ‘js’: GET /tutorials?title=js
Find all published Tutorials using GET /tutorials/published Api
Delete a Tutorial using DELETE /tutorials/:id Api
The Tutorial was removed from tutorials collection:
