Retrieving data from a ZIP File - NodeJS

Question

I asked myself a question,

I can read files (csv mainly) on a cloud platform but when it's a zip I just get a bunch of:

j�\lȜ��&��3+xT��J��=��y��7���vu�  {d�T���?��!�

Which is normal, so I wonder if there is a way to put that in a variable and unzip it using a lib or something like that.

Thanks for your time

Selmi Karim · Answer 1 · 2018-11-26T13:07:30.277

You should use jszip npm package. This allows you to quickly read zip files.

Example:

var fs = require("fs");
var JSZip = require("jszip");


    // read a zip file
    fs.readFile("project.zip", function(err, data) {
        if (err) throw err;
        JSZip.loadAsync(data).then(function (zip) {
          files = Object.keys(zip.files);
          console.log(files);
        });
    });

To read the contents of a file in the zip archive you can use the following. 

    // read a zip file
    fs.readFile("project.zip", function(err, data) {
        if (err) throw err;
        JSZip.loadAsync(data).then(function (zip) {

          // Read the contents of the 'Hello.txt' file
          zip.file("Hello.txt").async("string").then(function (data) {
            // data is "Hello World!"
            console.log(data);
          });

        });
    });

and to download the zip file from the server:

request('yourserverurl/helloworld.zip')
  .pipe(fs.createWriteStream('helloworld.zip'))
  .on('close', function () {
    console.log('File written!');
 });

But is there a way to use a variable containing the zip data instead of a file, as i mentionned i can only read the data from the plateform and not access it as a file — Quentin_otd, Nov 26 '18 at 13:01
request('yourserverurl/helloworld.zip') .pipe(fs.createWriteStream('helloworld.zip')) .on('close', function () { console.log('File written!'); }); — Selmi Karim, Nov 26 '18 at 13:08

score 2 · Accepted Answer · answered Nov 26 '18 at 12:52

you should use npm install node-stream-zip

const StreamZip = require('node-stream-zip');
const zip = new StreamZip({
    file: 'archive.zip',
    storeEntries: true
});

and get the info like this

zip.on('ready', () => {
    console.log('Entries read: ' + zip.entriesCount);
    for (const entry of Object.values(zip.entries())) {
        const desc = entry.isDirectory ? 'directory' : `${entry.size} bytes`;
        console.log(`Entry ${entry.name}: ${desc}`);
    }
    // Do not forget to close the file once you're done
    zip.close()
});

Hope it helps :-)

I'll give it a try, but can i use a variable containing the zip data instead of a file path ? — Quentin_otd, Nov 26 '18 at 13:02

whoami - fakeFaceTrueSoul · Answer 3 · 2023-06-02T16:39:28.823

Scenario1: If an API's response is a zipped file (E.x. Few Microsoft Graph APIs response is a zipped file), you can use npm unzipper & request packages to extract data to an object.

const unzipper = require('unzipper');
const request = require('request');

//Read zip file as stream from URL using request.
const responseStream = request.get({ url: ''}); 
let str = '';

responseStream.on('error', (err) => {
    if (err) { console.error(err); throw err; }
});

responseStream.pipe(unzipper.Parse())
    .on('entry', (entry) => {
        entry.on('data', (chunk) => {
            //Convert buffer to string (add trim to remove any unwanted spaces) & append to existing string at each iteration.
            str += chunk.toString().trim();
        }).on('end', () => {
            const respObj = JSON.parse(str); //At the end convert the whole string to JSON object.
            console.log(respObj);
        });
    });

Ref: read-zipped-file-content-using-nodejs

Scenario2: If you wanted to read zipped file from a server i.e., local.

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

const readStream = fs.createReadStream(`filePath`);
let str = '';

readStream.on('error', (err) => {
    if (err) { console.error(err); throw err; }
});

readStream.pipe(unzipper.Parse())
    .on('entry', (entry) => {
        entry.on('data', (chunk) => {
            //Convert buffer to string (add trim to remove any unwanted spaces) & append to existing string at each iteration.
            str += chunk.toString().trim();
        }).on('end', () => {
            const respObj = JSON.parse(str); //At the end convert the whole string to JSON object.
            console.log(respObj);
        });
    });

Retrieving data from a ZIP File - NodeJS

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