How to Download and Extract a Zip File with Node

Downloading and extracting a zip file using Node seemed like a pretty easy task but alas it took some time to figure out.

While researching how to do this, I didn’t find a library that had all of the requirements within it but I did find a few that allowed me to meet the requirements

Requirements

1. Download zip file from a url
2. Extract zip file to a directory location
3. Extract a single directory and all of its sub-directories within the zip file

Downloading the Zip File

Step 1 was to get the zip file downloaded using Node and make sure that I could manually open it. To download the zip file, I am using the superagent package and piping the download to a file using fs.

1. Install superagent package

   npm install --save superagent
   

2. Using superagent along with fs we can download a zip file and save the zip to a local file. In the code below, I am downloading the zip for the master branch of the Github repo located at https://github.com/digitaldrummerj/node-zip-download-sample.

   There are “TODO” statements in the code below for the things that you would need to change to use this code for your own zip file.

   'use strict';
   
   // Import
   const request = require('superagent');
   const fs = require('fs');
   
   // TODO: change to where your zip file is located
   const repoName = 'node-zip-download-sample';
   const href = `https://github.com/digitaldrummerj/${repoName}/archive`;
   const zipFile = 'master.zip';
   
   const source = `${href}/${zipFile}`;
   
   // TODO: change to the directory instead of the zip that you want to extract
   const extractEntryTo = `${repoName}-master/`;
   
   // TODO: change to the directory where you want to extract to
   const outputDir = `./${repoName}-master/`;
   
   request
     .get(source)
     .on('error', function(error) {
       console.log(error);
     })
     .pipe(fs.createWriteStream(zipFile))
     .on('finish', function() {
         // add code below to here
     });
   

Now that the zip file is downloaded we can unzip it.

Unzipping the Zip File

For unzipping, I didn’t find anything built into Node but I did find the Adm-Zip package on NPM.

Adm-Zip has functions for dealing with the entire zip file or a single file/directory within the zip file. In my case all of my files were contained within a directory in the zip file and I wanted to extract the files contained within that directory.

1. Install Adm-Zip

   npm install --save adm-zip
   

2. Add Adm-Zip to the list of requires

   const admZip = require('adm-zip');
   

3. Within the on finish statement from the previous section, add the code below to use Adm-Zip to extract a directory from the downloaded zip file and extract it to a directory

   console.log('finished downloading');
   var zip = new admZip(zipFile);
   console.log('start unzip');
   zip.extractEntryTo(extractEntryTo, outputDir, false, true);
   console.log('finished unzip');
   

Just like that we had our zip file downloaded and extracted to a directory.

You can find a working sample at https://github.com/digitaldrummerj/node-zip-download-sample

Leave a comment below if you end up using this solution or are doing it another way.