nodejs compressed file installation

Node.js is a popular open source JavaScript runtime that can run on the server and provides efficient I/O operations and code execution capabilities. Compressing files is a common task in Node.js, as it effectively reduces file size, increases transfer speed, and reduces storage costs. In this article, you will learn how to use compressed files in Node.js and install the necessary tools.

Install Node.js

Before compressing files, you need to install Node.js first. The latest stable version of Node.js can be downloaded from the official website (https://nodejs.org/en/). The installation process is basically just follow the steps.

Install compressed file module

Node.js provides many modules that can be used to compress files, the most commonly used are the zlib module and gzipmodule. zlib The module provides data compression and decompression functions and supports compression formats such as gzip, deflate, and zlib. The gzip module provides Gzip compression and decompression functions.

Install zlib module

You can use the following command to install the zlib module:

npm install zlib --save

Install the gzip module

You can use the following command to install it gzipModule:

npm install gzip --save

Compressed files

Use zlib module to compress files

The following is a compressed file using zlib module Example:

const fs = require('fs');
const zlib = require('zlib');

// 读取文件
const readStream = fs.createReadStream('myfile.txt');

// 压缩文件
const writeStream = fs.createWriteStream('myfile.txt.gz');
const gzip = zlib.createGzip();
readStream.pipe(gzip).pipe(writeStream);

// 压缩完成后进行回调
writeStream.on('finish', () => {
  console.log('文件已压缩。');
});

Code analysis:

• Read file: Create a stream to read the file and read the contents of the myfile.txt file.
• Compressed file: Create a stream for writing files and save the compressed file as myfile.txt.gz. At the same time, create a gzip object for compressing files.
• Pipe stream: pass the stream that reads the file to the pipe, pass the file to the gzip object through the pipe for compression, and then pass the compressed data to the stream that writes the file to save.
• Callback function: When the compression is completed, the callback function is executed and "the file has been compressed" is output.

Use the gzip module to compress files

The following is an example of using the gzip module to compress files:

const fs = require('fs');
const gzip = require('gzip');

// 读取文件
const readStream = fs.createReadStream('myfile.txt');

// 压缩文件
const writeStream = fs.createWriteStream('myfile.txt.gz');
readStream.pipe(gzip()).pipe(writeStream);

// 压缩完成后进行回调
writeStream.on('finish', () => {
  console.log('文件已压缩。');
});

Code analysis:

• Read the file: Create a stream to read the file and read the contents of the myfile.txt file.
• Compressed file: Create a stream for writing files and save the compressed file as myfile.txt.gz. Use the gzip() function to create a gzip object for compressing files.
• Pipe stream: pass the stream that reads the file to the pipe, pass the file to the gzip object through the pipe for compression, and then pass the compressed data to the stream that writes the file to save.
• Callback function: When the compression is completed, the callback function is executed and "the file has been compressed" is output.

Decompress files

The process of decompressing files is similar to that of compressing files. You only need to use the corresponding decompression method. The following is an example of decompressing a zlib compressed file:

const fs = require('fs');
const zlib = require('zlib');

// 读取压缩文件
const readStream = fs.createReadStream('myfile.txt.gz');

// 解压文件
const writeStream = fs.createWriteStream('myfile.txt');
const gunzip = zlib.createGunzip();
readStream.pipe(gunzip).pipe(writeStream);

// 解压完成后进行回调
writeStream.on('finish', () => {
  console.log('文件已解压。');
});

Code analysis:

• Read the file: Create a stream to read the file, read The contents of compressed file myfile.txt.gz.
• Decompress the file: Create a stream to write the file, and save the decompressed file as myfile.txt. At the same time, create a gunzip object for decompressing files.
• Pipe stream: pass the stream of the read file to the pipe, pass the file to the gunzip object through the pipe for decompression, and then pass the decompressed data to the write file stream to save.
• Callback function: When decompression is completed, the callback function is executed and "the file has been decompressed" is output.

Conclusion

In Node.js, compressing files is a very useful feature that can make files smaller, faster to transfer, and cheaper to store. This article introduces how to use the zlib module and the gzip module in Node.js to compress and decompress files, as well as install the necessary tools. The above sample code is for reference, and readers can modify and implement it according to actual needs.

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