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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