Nodejs settings prohibit cross-domain

As web applications develop and become more complex, cross-domain requests become more frequent. Simply put, cross-domain request means sending a request from one page or domain name to another domain name. Cross-domain requests are not a good thing when it comes to security, as they can be used to cause security issues. In this article, we will explore how to set up a cross-domain ban with Node.js.

What is cross-domain

Cross-domain request means that a page from one domain name requests resources from another domain name. For example, if you try to load http://test2.com/image.jpg on the page http://test1.com, it will cause a cross-domain request. In web browsers, cross-domain requests are prohibited by default. As shown in the image below, requests from different domains are blocked.

In terms of security, this is a very good feature. Because if malicious users are able to send requests to other websites, then they can attack those websites and obtain potentially confidential information. Therefore, the browser prohibits cross-origin requests unless explicitly allowed.

How to ban cross-domain requests

Now let’s take a look at how to use Node.js to set up ban cross-domain requests. In order to prohibit cross-domain requests, we need to configure something on the server side. Below is a simple example showing how to disable cross-origin requests using Node.js.

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

const app = express();

// 允许只来自example.com的跨域请求
const corsOptions = {
  origin: 'http://example.com',
  optionsSuccessStatus: 200
};

app.use(cors(corsOptions));

// ... 其他路由

app.listen(3000, () => {
  console.log('Server listening on port 3000.');
});

In this example, we use the Express framework and CORS middleware to configure the server to prohibit cross-domain requests. First, we define a corsOptions object, where the origin attribute specifies which domain requests are allowed. Its value can be a string representing a single domain, or it can be a function. to allow multiple domains.

We then apply the CORS middleware to our Express application. This middleware will check all incoming requests and include the Access-Control-Allow-Origin header in the response if they come from an allowed domain.

Using the above code, we only allow requests from http://example.com and return a 200 status code to indicate success. If the request contains an illegal source domain, the server will return a 403 status code to reject the request.

It should be noted that if we use a different protocol or port number, it will also be regarded as a different domain name. For example: http://example.com and https://example.com, or http://example.com and http: //example.com:3000.

Conclusion

In this article, we learned what cross-domain is and why it needs to be banned. We also covered how to set up a method to disable cross-origin requests using Node.js, and provided a complete example. This is a smart and secure way to ensure your web application is protected from the threat of cross-domain attacks.

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