USING POSTMAN TO TEST THE APIS
Run the server type
npm init
node api.js
nodemon api
1. Install packages:
npm install pg --save npm install express --save npm install body-parser --save npm install nodemon --save 2. Create Database Connection:
Create a file called connection.js
This file would hold the connection data as shown below:
const { Client } = require("pg"); const client = new Client({ host: "localhost", user: "postgres", port: 5432, password: "postgres", //password: "sa", database: "postgres", }); module.exports = client; 3. Create the Server and Client
Node.js allows us to create a server. Now we need to create a second file.
Here I call it api.js
Write the following code inside. This code creates a server listening at port 3300. Then a client is create as well that connects to the server.
const client = require("./connection.js"); const express = require("express"); const app = express(); app.listen(3300, () => { console.log("Sever is now listening at port 3300"); }); client.connect(); Add the BodyParser: This is used to handle conversion to and from json.
const bodyParser = require("body-parser"); app.use(bodyParser.json()); 4. Get All Users
for GET requests, we use app.get() function. This function takes two parameters: the route /users and a callback. The callback is an arrow function that executes when a request is received. The callback take two parameter: request and response. Inside the callback, we use the client to query the database and then send the result back.
app.get("/users", (req, res) => { client.query(`Select * from users`, (err, result) => { if (!err) { res.send(result.rows); } }); client.end; }); 5. Get User By Id
// TODO: Get user by id app.get("/users/:id", (req, res) => { client.query( `Select * from users where id=${req.params.id}`, (err, result) => { if (!err) { res.send(result.rows); } } ); client.end; }); 6. Add New User
// TODO: Add new user: app.post('/users', (req, res)=> { const user = req.body; let insertQuery = `insert into users(id, firstname, lastname, location) values(${user.id}, '${user.firstname}','${user.lastname}', '${user.location}')` client.query(insertQuery, (err, result)=>{ if(!err){ res.send('Insertion was successful') } else{ console.log(err.message) } }) client.end; }) 7. Update User Details:
//TODO: update all user data app.put('/users/:id', (req, res)=> { let user = req.body; let updateQuery = `update users set firstname = '${user.firstname}', lastname = '${user.lastname}', location = '${user.location}' where id = ${user.id}` client.query(updateQuery, (err, result)=>{ if(!err){ res.send('Update was successful') } else{ console.log(err.message) } }) client.end; }) 8. Delete Data:
// TODO: Delete the data app.delete('/users/:id', (req, res)=> { let insertQuery = `delete from users where id=${req.params.id}` client.query(insertQuery, (err, result)=>{ if(!err){ res.send('Deletion was successful') } else{ console.log(err.message) } }) client.end; }) 
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