How To Download And Unzip A Zip File In Memory In Nodejs

Downloading and unzipping files are common tasks in software development, especially for Node.js developers. In this article, we will dive into a step-by-step guide on how to efficiently download and unzip a zip file in memory using Node.js. This process can be incredibly useful for handling file operations in your projects.

Firstly, let's explore how to download a zip file from a given URL in Node.js. To accomplish this, we will use the popular 'axios' library for making HTTP requests. You can install axios by running the following command in your Node.js project:

npm install axios

Once you have axios installed, you can use the following code snippet to download a zip file in Node.js:

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

const downloadZipFile = async (url) => {
  const response = await axios({
    method: 'GET',
    url: url,
    responseType: 'stream',
  });

  response.data.pipe(fs.createWriteStream('example.zip'));

  return new Promise((resolve, reject) => {
    response.data.on('end', () => {
      resolve();
    });

    response.data.on('error', (err) => {
      reject(err);
    });
  });
};

// Replace 'url-to-your-zip-file' with the actual URL of the zip file
downloadZipFile('url-to-your-zip-file')
  .then(() => {
    console.log('Zip file downloaded successfully!');
  })
  .catch((err) => {
    console.error('Error downloading zip file:', err);
  });

In the code snippet above, we define a function `downloadZipFile` that takes a URL parameter, downloads the zip file from the provided URL, and saves it to the disk with the name 'example.zip'.

Next, let's move on to unzipping the downloaded file in memory. For this task, we will use the 'jszip' library, a powerful tool for working with zip files in Node.js. You can install jszip by running the following command:

npm install jszip

Here's how you can unzip the downloaded file in memory using jszip:

const JSZip = require('jszip');
const fs = require('fs');

const unzipFileInMemory = async () => {
  const zipData = fs.readFileSync('example.zip');
  const zip = await JSZip.loadAsync(zipData);

  zip.forEach(async (relativePath, file) => {
    const content = await file.async('nodebuffer');
    // Do something with the unzipped file content
  });
};

unzipFileInMemory()
  .then(() => {
    console.log('Zip file unzipped successfully in memory!');
  })
  .catch((err) => {
    console.error('Error unzipping zip file:', err);
  });

In this code snippet, we load the downloaded zip file 'example.zip' using jszip and iterate over its contents. For each file within the zip, you can access its content and perform further operations with it.

By following these simple steps, you can efficiently download and unzip a zip file in memory using Node.js. This technique can be valuable for various applications where handling zip files is a common requirement. Happy coding!