30 Days of node
Day 16 : Zlib Module



30 days of node - Nodejs tutorial series

  1. Day 1 - The Beginning
  2. Day 2 - File System in node.js
  3. Day 3 - Regular expressions in node.js
  4. Day 4 - Console module in node.js
  5. Day 5 - All about errors
  6. Day 6 - Array methods
  7. Day 7 - All about NPM
  8. Day 8 - Publishing package on NPM
  9. Day 9 - Crypto Module ( Hashing and HMAC)
  10. Day 10 - Crypto Module ( Encryption and Decryption )
  11. Day 11 - Express Framework
  12. Day 12 - CRUD in MongoDB using node.js
  13. Day 13 - Sign Up form in node.js
  14. Day 14 - Introduction to socket.io
  15. Day 15 - All about streams
  16. Day 16 - Zlib Module
  17. Day 17 - CRUD in MySQL using node.js
  18. Day 18 - Concepts of callbacks in node.js
  19. Day 19 - Query String in node.js
  20. Day 20 - Timers in node.js
  21. Day 21 - Buffers in node.js
  22. Day 22 - String Decoder Module in node.js
  23. Day 23 - Debugger module in node.js
  24. Day 24 - Child Processes in node.js
  25. Day 25 - Clusters in node.js
  26. Day 26 - OS module in node.js
  27. Day 27 - Assert module in node.js
  28. Day 28 - Getting Tweets using node.js
  29. Day 29 - Uploading file to dropbox using node.js
  30. Day 30 - Github API with node.js

zlib

  • zlib module is used to provide compression and decompression functionalities in node.js .
  • In simple words , it is used to zip or unzip files.
  • These functionalities are implemented using GZIP and deflate/inflate .
  • We can use the zlib module via requiring it in the following way : 
    											
var zlib = require('zlib');

Compress a file using node.js zlib module

Code snippet to demostrate how we can compress a file in node.js using zlib module : 
											
// Including the required modules	
var zlib = require('zlib');
var fs = require('fs');

var zip = zlib.createGzip();

var read = fs.createReadStream('newfile.txt');
var write = fs.createWriteStream('newfile.txt.gz');
//Transform stream which is zipping the input file
read.pipe(zip).pipe(write);	
console.log("Zipped Successfully");

Decompress a file using node.js zlib module

Code snippet to demostrate how we can decompress a file in node.js using zlib module : 
											
// Including the required modules	
var zlib = require('zlib');
var fs = require('fs');

var unzip = zlib.createUnzip();

var read = fs.createReadStream('newfile.txt.gz');
var write = fs.createWriteStream('unzip.txt');
//Transform stream which is unzipping the zipped file
read.pipe(unzip).pipe(write);	
console.log("unZipped Successfully");

Methods of zlib module :

  • createDeflate()
  • createInflate()
  • createDeflateRaw()
  • createInflateRaw()
  • deflateSync()
  • inflateSync()
  • deflateRaw()
  • inflateRaw()
  • deflateRawSync()
  • inflateRawSync()
  • gzip()
  • unzip()
  • gzipSync()
  • unzipSync()
  • createGzip()
  • createGunzip()

Summary

In this chapter of 30 days of node tutorial series, we learned how we can compress and decompress files using zlib module of node.js. Also we leaned about all the methods available in zlib module.