Simple todo API with complex concepts

#beginners #api #mongodb #database

Getting started

In this article you will learn how to build a simple todo API using Nodejs. Nodejs is an open-source , JavaScript runtime environment use foe backend development. It's is used by the tech giants all over the world having wonderful community support and well structured documentation.

Install the dependencies

Before you satrt building the API you must install the following dependencies mentioned below.

nodejs
expressjs
mongoosejs
Mongodb
clone this repo After you clone the github repo open the folder named hc-api-eventin the terminal and hit npm install, this will install all the required packages mentioned in the package.json file.

The File structure

Import the modules

To start using the libraries we need to import them first

/*Importing the moudule*/
const express = require('express');
const mongoose = require('mongoose');
const app = express()
app.use(express.json())
require('dotenv').config();

Connect the database and start the API

As we are building a todo API so we need to store the data todo's and there it comes the need of database.Database is an organized way to store collection of data just like taking down notes in a notebook.We are using Mongodb which is a popular nosql database.So to store the todo's into the database first we need to connect our API with Mongodb. We will use the mongoose instance which is having a connectfuntion which takes two parameters one is the connection string which is necessary and other is options . Use the below piece of code to connect the database with the API

const start = () => {
    mongoose.connect(process.env.MONGODB_CONNECTION_STRING, {
        useNewUrlParser: true,
        useUnifiedTopology: true
    }).then(
        app.listen(5000, () => {
            console.log("App is listining ");
        })
    ).catch((err) => {
        console.log("Error ")
    })
}
start()

mongoose.connect() returns a promise which we are handling using then() and catch(). Here we are declaring that if the db connection is successfull then only start the API else catch the eror and stop the API. Now use our API we need to have some ednpoint so we are creating an HTTP server which will listen to port=5000, this is just like watching your favourite show on a particular channel out of many.

Designing the schema and creting the Model

Schemas are like skeleteal structures of data, It contains the necessary metadata of the data we are passing into the database. Suppose our data is related to a person so there will be a property named say name of type string which is required or say a property named isEmployed of type boolean and defalut value will be false

person schema :{
 isEmployed : { type: Boolean, default: false },
  Name: {type: String, required: true}

}

Model on the other hand provides an interface to the database for creating, querying, updating, deleting records, etc.

// Mongodb Schema & Model 
const todoSchema = mongoose.Schema({
    todo: String
})
const Todo = mongoose.model('Todo', todoSchema)

Designing the API request

Let me tell you that the behavior of an API is to accept a request and then pass a desired response. The request contains are metadata about what we want, in which form we are requesting the data, from which browser, which IP and a lot more similarly a response all the metadata taht we are passing to the Cient. In CRUD architechture we deal with 4 types of requests get Reading , post for Creating , put for updating and delete for deleting.So,Now we have created a model named Todo and we can use it to interact with our db.

`Get All Todo's`

We will just grab all the todo's using find() and pass it as a response

app.get('/', async (req, res) => {
    const data = await Todo.find();
    res.json(data)
})

`Create a Todo`

We will use the create() and will store the todo in the db

app.post('/', async (req, res) => {
    const data = await Todo.create(req.body);
    res.send(data)
})

Working with a particular document

Every doccument Mongodb creates it generated an ID. ID's are necessary to filter documents having similar property, just like there can be two employees with same name and same height but will have different employee ID's. Just like that every documnet we create mongobd automatically generates an Unique ID for it . Now we will be using these id in our request to filter data

`Get a single Todo`

As I have stated that our request contains all the metadata so we will be grabing the id of a todo from the request params and will us to filter that particular todo from our db using the findById

app.get('/:id', async (req, res) => {
    const data = await Todo.findById(req.params.id);
    res.json(data)
})

`Update a Todo`

We will use a method named findByIdAndUpdate and there will pass the id of the todo we want to delete followed by req.body with conataines the updated todo and lastly we will pass a option new which will be set to true

app.put('/:id', async (req, res) => {
    const data = await Todo.findByIdAndUpdate(req.params.id, req.body, { new: true })
    res.send(data)
})

`Delete a Todo`

Finally we will use the same approach to delete a todo using a method named findByIdAndUpdate and will pass the todo idand our todo will be deleted.

app.delete("/:id", async (req, res) => {
    const data = await Todo.findByIdAndDelete(req.params.id)
    res.send("Todo deleted")
})

The Final code

/*Importing the moudule*/
const express = require('express');
const mongoose = require('mongoose');
const app = express()
app.use(express.json())
require('dotenv').config();

// Mongodb Schema & Model 
const todoSchema = mongoose.Schema({
    todo: String
})
const Todo = mongoose.model('Todo', todoSchema)


//api requests 

app.get('/', async (req, res) => {
    const data = await Todo.find();
    res.json(data)
})
app.post('/', async (req, res) => {
    const data = await Todo.create(req.body);
    res.send(data)
})
app.get('/:id', async (req, res) => {
    const data = await Todo.findById(req.params.id);
    res.json(data)
})

app.put('/:id', async (req, res) => {
    const data = await Todo.findByIdAndUpdate(req.params.id, req.body, { new: true })
    res.send(data)
})

app.delete("/:id", async (req, res) => {
    const data = await Todo.findByIdAndDelete(req.params.id)
    res.send("Todo deleted")
})



const start = () => {
    mongoose.connect(process.env.MONGODB_CONNECTION_STRING, {
        useNewUrlParser: true,
        useUnifiedTopology: true
    }).then(
        app.listen(5000, () => {
            console.log("App is listining ");
        })
    ).catch((err) => {
        console.log("Error ")
    })
}

Key Take aways

Request & Response
CRUD Architechture
Mongoose model, Schema & simple data filtering

Conclusion

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