Express Install , MVC architecture concept , Nodemon install , express server configuration , Postman Install , basic get() , post() operations in api and testing using postman.
Express Install , MVC architecture concept , Nodemon install , express server configuration , Postman Install , basic get() , post() operations in api and testing using postman.
Here's a basic guide to get you started on your first day with Express:
1. Express Installation
- Step 1: Make sure Node.js is installed on your system. You can check this by running:
```bash
node -v
npm -v
```
- Step 2: Initialize a new Node.js project by running:
```bash
npm init -y
```
- Step 3: Install Express using npm:
```bash
npm install express --save
```
2. MVC Architecture Concept
- Model: Handles the data logic (e.g., database interaction).
- View: Manages the display of data (e.g., HTML, templates).
- Controller: Handles the business logic, processes requests, and returns responses.
- Express is often used with MVC to separate concerns, making the code more organized and maintainable.
3. Nodemon Installation
- Nodemon automatically restarts the server when file changes in the directory are detected.
- Install Nodemon globally:
```bash
npm install -g nodemon
```
- Alternatively, you can install it as a dev dependency:
```bash
npm install --save-dev nodemon
```
4. Express Server Configuration
- Create a basic Express server:
```javascript
const express = require('express');
const app = express();
const port = 3000;
app.get('/', (req, res) => {
res.send('Hello, World!');
});
app.listen(port, () => {
console.log(`Server is running on http://localhost:${port}`);
});
```
- Run the server using:
```bash
node app.js
```
- Or, using Nodemon:
```bash
nodemon app.js
```
5. Postman Installation
- Download and install Postman from [here](https://www.postman.com/downloads/).
- Postman is a tool for testing APIs by sending HTTP requests to your server.
6. Basic `get()` and `post()` Operations
- GET Request:
```javascript
app.get('/api/data', (req, res) => {
res.json({ message: 'GET request received!' });
});
```
- POST Request:
```javascript
app.use(express.json());
app.post('/api/data', (req, res) => {
const data = req.body;
res.json({ message: 'POST request received!', data });
});
```
7. Testing Using Postman
- Open Postman and create a new request.
- For a GET request:
- Select `GET` method, enter `http://localhost:3000/api/data`, and click `Send`.
- For a POST request:
- Select `POST` method, enter `http://localhost:3000/api/data`, go to the `Body` tab, select `raw`, and choose `JSON` as the format.
- Enter some JSON data (e.g., `{"name": "John"}`) and click `Send`.
This should give you a solid foundation to start working with Express.
------------------------------------------------------------------------------------------------------
server.js
const express=require('express');
//object create
const app=express();
const port=4000;
//configuration code for accepting json data / form data from ui
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.get('/',(req,res)=>{
res.send("<h3>Welcome to my Express Application and Coding and be Happy</h3>");
})
app.get('/test1',(req,res)=>{
res.send("<ul><li>hello kolkata</li><li>hello pune</li></ul>");
})
app.get('/test2',(req,res)=>{
let emp={id:10,nm:'raj',age:33,city:['pune','goa','punjab']};
res.json(emp);
})
app.post('/insert',(req,res)=>{
let data=req.body;
console.log(data);
res.status(200).json({msg:"thank you data received"});
})
app.post('/login',(req,res)=>{
let data=req.body;
if(data.uid=="sourav07" && data.pwd=="1234")
{
res.status(200).json({msg:"user is valid"});
}
else
{
res.status(200).json({msg:"user is invalid"});
}
})
app.get('/edit/:uid',(req,res)=>{
let id=req.params.uid;
console.log("Required id :"+id);
res.status(200).json({msg:"id received"});
})
app.listen(port,()=>{
console.log(`server is running in the port ${port}`);
})
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