Today we want to make a url shortener in nodejs. This project won't use a database to save the data, All the data will be saved in JSON file.
first of all, make sure you have installed nodejs. You can use nvm(Node version manager) to install it if you're using Linux.
Let's make the folder we want to code in there:
mkdir url-short
cd url-short
We can make a public/ directory to put out HTML and CSS files in there. So:
mkdir public/
And we will make a index.html in public/:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<form action="/" method="post">
<h1>Link shortener</h1>
<input type="text" name="origUrl" id="">
<button type="submit">shorten</button>
</form>
</body>
</html>
and index.css again in public/:
body{
background-color: #00796B;
}
h1{
color: #fff;
font-size: 2em;
font-weight: bold;
text-align: center;
margin: 0;
font-family: Arial, Helvetica, sans-serif;
}
input{
width: 70%;
height: 2em;
border: none;
border-bottom: 1px solid #fff;
background-color: #fff;
color: #000;
font-size: 1em;
font-family: Arial, Helvetica, sans-serif;
border-radius: 50px;
margin-top:50px;
}
button{
background-color: #1A237E;
color: #fff;
font-size: 1em;
font-family: Arial, Helvetica, sans-serif;
border: 0;
border-radius: 50px;
width: 70px;
height: 40px;
}
And now we will install npm package we need:
npm i express
So We make a db.json in the root:
{links:[]}
We will add urls to this later.
and index.js in the root:
const express = require("express")
const app = express()
const process = require("process")
const fs = require("fs")
const port = process.env.PORT || 4000
app.use(express.json())
app.use(express.urlencoded({ extended: true }))
// load html and css in public folder
app.use(express.static("public"))
app.get("/", (req, res) => { res.sendFile("index.html") })
Ok So we know that index.html will send a post request to / containing original Url and we can get the data from db.json and chack if we have saved this url earlier:
app.post("/", (req, res) => {
let newJson=JSON.parse(fs.readFileSync("./db.json"))
const {origUrl} = req.body;
// check if url isn't in json
newJson.links.forEach(element => {
if (element.url===origUrl) {
res.send(`<h1>Your shorted link is http://localhost:${port}/${element.id}</h1>`)
}
But what if we haven't? We can make a id and store it json:
// make the short id and put it in db.json
let id = Math.random() * 10000000;
id=Math.floor(id)
// push to json
newJson.links.push({
id:id,
url:origUrl
})
fs.writeFileSync("./db.json",JSON.stringify(newJson))
res.send(`<h1>Your short url is: http://localhost:${port}/${id}</h1>`)
})
Ok, So we saved the id with the original url. But if the user went to that id we must redirect the user to original url:
app.get("/:id",(req,res)=>{
// redirect
const id=req.params.id
let newJson=JSON.parse(fs.readFileSync("./db.json"))
let link=newJson.links.find(link=>link.id==id)
if(link){
res.redirect(link.url)
}
else{
res.send("no link found")
}
})
app.listen(port, () => console.log(`app listening on port ${port}!`))
And so it works
demo :
Also I have uploaded the code in github: link
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