How to set head utf8 in nodejs

Node.js is a popular server-side programming language with a powerful asynchronous event-driven mechanism and a rich module library. Many websites and applications use it to build high-performance, reliable server-side programs. When developing Node.js applications, it is sometimes necessary to set the header of the HTTP response message, especially the character set encoding (charset), to ensure correct text display and delivery. This article explains how to set the character set encoding in HTTP response headers using Node.js.

1. Understanding character set encoding

Before introducing how to set character set encoding, we first need to understand what character set encoding is. A character set encoding is a standard for describing the mapping between text characters and their binary codes, the most common of which are UTF-8 and ASCII encodings.

UTF-8 is a variable-length encoding scheme that can use binary codes of different lengths according to different character choices. It supports all Unicode characters and is compatible with ASCII encoding. Therefore, in practical applications, UTF-8 is the most commonly used character set encoding.

ASCII encoding is a standard for representing text characters using 7- or 8-bit binary codes, where each character corresponds to a unique binary code. It is the American Standard Code for Information Interchange. It is only compatible with English and Latin alphabets and cannot support international characters.

2. Set the character set encoding of the HTTP header

It is very easy to set the character set encoding of the HTTP response header in Node.js, just use the res.setHeader method That’s it. For example, we can use the following code to set the character set encoding of the HTTP response header to UTF-8:

const http = require('http');

const server = http.createServer((req, res) => {
  res.setHeader('Content-Type', 'text/html; charset=utf-8');
  res.write('你好世界');
  res.end();
});

server.listen(3000);

In this example, we first use the require method to introduce the http module of Node.js and create a HTTP server. In the callback function of the server responding to the request, we use the res.setHeader method to set the value of the Content-Type header to text/html; charset=utf-8, and then use the res.write and res.end methods to send it to the client. A text containing Chinese characters. During this process, Node.js will automatically encode the text into UTF-8 format and add it to the body part of the HTTP response message.

It should be noted that if the Content-Type header is not set before sending the HTTP response, Node.js will set it to text/plain format by default, which may cause the text to be displayed incorrectly. . Therefore, it is important to set the correct character set encoding when building HTTP applications.

3. Set the default character set encoding

In actual applications, we may need to set a default value for the character set encoding of the HTTP response header to facilitate us Used in multiple responses. In Node.js, we can set the default character set encoding of HTTP response headers using the res.charset property. For example, we can use the following code to set the default charset encoding of the HTTP response header to UTF-8:

const http = require('http');

const server = http.createServer((req, res) => {
  res.charset = 'utf-8';
  res.write('你好世界');
  res.end();
});

server.listen(3000);

In this example, we use the res.charset attribute to set the default charset encoding of the HTTP response header. Character set encoding is set to UTF-8. Thereafter, we can use the res.write method to send text containing Chinese characters to the client in any HTTP response without needing to set the character set encoding again.

4. Summary

In this article, we introduced what character set encoding is and demonstrated how to set HTTP response header characters in a Node.js application Set encoding to ensure correct text display and delivery. By using the res.setHeader and res.charset properties, we can quickly and easily set the character set encoding to build a high-performance, reliable HTTP server program.

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