What are the common Express.js operations in PHP programming?

What are the Express.js operations in PHP programming?

The PHP programming language is one of the most popular web development languages ​​today. In PHP, there are many popular frameworks and libraries that can be used to simplify programming and speed up the development process. One of the popular frameworks is Express.js, which is a Node.js-based web application framework. Its flexibility and scalability make it a good choice to use in PHP programming. In this article, we will introduce common Express.js operations in PHP programming.

1. Create a web server

You can easily create a web server using PHP and Express.js. You need to install Node.js and Express.js, and create a server file with the following code:

const express = require('express');
const app = express();

app.get('/', function(req, res) {
   res.send('Hello World');
});

app.listen(3000, function() {
   console.log('Server started on port 3000');
});

In the above example, we created a simple web server using Express.js, which Listens on port 3000 and provides HTTP service on that port. We also define a GET route that will return "Hello World" as a response.

2. Handling form data

When writing web applications, it is very common to process form data. Express.js handles POST requests and extracts form data just fine. Here is an example of handling a POST request:

app.post('/process-form', function(req, res) {
   const name = req.body.name;
   const email = req.body.email;
   const password = req.body.password;

   // Process the form data here...
});

In the above code, we have defined a POST route that handles a form named "process-form". When the form is submitted, Express.js will parse the request body and make it available as a req.body object. We can extract form data from this object and process it.

3. Handling routing

Route handling is very important when writing web applications. You can use Express.js to define and handle routes. Here are some examples of handling routing:

// Simple GET route
app.get('/about', function(req, res) {
   res.send('About us');
});

// Dynamic route
app.get('/user/:id', function(req, res) {
   const id = req.params.id;
   res.send(`User ID: ${id}`);
});

// Route with middleware
app.get('/protected', isAuthenticated, function(req, res) {
   res.send('Protected page');
});

// 404 page
app.use(function(req, res, next) {
   res.status(404).send('Page not found');
});

In the above example, we have defined different types of routes. The first is a simple GET route that just returns a string. The second is a dynamic route that extracts parameters from the URL and outputs them. The third is a route that requires authentication, which uses middleware to check if the user is already logged in. The last one is a 404 page that will serve as the default route if no route is found.

4. Using template engines

In PHP programming, it is very common to use template engines to create dynamic content. Express.js allows you to use different template engines to create dynamic content. The following is an example of using the EJS template engine:

// Set EJS as the view engine
app.set('view engine', 'ejs');

// Render a template
app.get('/post/:id', function(req, res) {
   const id = req.params.id;
   const title = 'My Blog Post';

   res.render('post', { id: id, title: title });
});

In the code above, we first set up EJS as the view engine. We then defined a GET route that would render the content using the post.ejs template. When rendering the template, we use a JavaScript object as a parameter that contains the variables extracted from the route. In templates, you can use these variables to create dynamic content.

5. Using middleware

Middleware is very important in Express.js. You can use it to add functionality, handle requests, authenticate users and define error handlers. Here is an example of using middleware:

// Logger middleware
app.use(function(req, res, next) {
   console.log(`${req.method} ${req.url}`);
   next();
});

// Authentication middleware
function isAuthenticated(req, res, next) {
   if (req.isAuthenticated()) {
      return next();
   }

   res.redirect('/login');
}

// Error handling middleware
app.use(function(err, req, res, next) {
   console.error(err.stack);
   res.status(500).send('Internal Server Error');
});

In the above code, we have defined three different middlewares. The first is a simple logger that prints the requested method and URL. The second is an authentication middleware that checks if the user is already logged in. The third is the error handling middleware, which prints an error when an error occurs and returns a 500 Internal Server Error response.

Summary

In this article, we introduced some common Express.js operations in PHP programming. Using these operations, you can easily create web servers, process form data, handle routing, use template engines, and use middleware. These operations make programming with PHP and Express.js easier and more flexible. Whether you are a newbie or an experienced PHP developer, mastering these operations is very useful.

The above is the detailed content of What are the common Express.js operations in PHP programming?. For more information, please follow other related articles on the PHP Chinese website!