Node.js - ZLIB Gunzip returns empty file

node.js, zlib

Solution

Node streams are asynchronous, so both of your streams will run at the same time. That means that when you initially open `inp2` that `file.txt.gz` is empty, because the other write stream hasn't added anything to it yet.

var zlib = require('zlib') ,
    fs = require('fs');

var src = 'file.txt',
    zip = 'file.txt.gz',
    dst = 'output.txt';

var inp1 = fs.createReadStream(src);
var out1 = fs.createWriteStream(zip);

inp1.pipe(zlib.createGzip()).pipe(out1);

out1.on('close', function(){
  var inp2 = fs.createReadStream(zip);
  var out2 = fs.createWriteStream(dst);
  inp2.pipe(zlib.createGunzip()).pipe(out2);
})

Problem

I'm just testing ZLIB of Node.js but quickly facing strange results. Here is my script (inspired from the Node.js manual example http://nodejs.org/api/zlib.html#zlib_examples): ``` var zlib = require('zlib') , fs = require('fs') , inp1 = fs.createReadStream('file.txt') , out1 = fs.createWriteStream('file.txt.gz') , inp2 = fs.createReadStream('file.txt.gz') , out2 = fs.createWriteStream('output.txt') ; inp1.pipe(zlib.createGzip()).pipe(out1); /* Compress to a .gz file*/ inp2.pipe(zlib.createGunzip()).pipe(out2); /* Uncompress the .gz file */ ``` In this example, and before executing the script, I created a file called `file.txt` and I fullfill it with a sample text (say a Lorem Ipsum). The previous script creates successfully the `.gz` file, that I can unzip from the finder (I'm on Mac OSX), but the uncompressed `output.txt` file is empty. Why? Do you have any idea?

Original source