How do I ungzip (decompress) a NodeJS request's module gzip response body?

Question

How do I unzip a gzipped body in a request\'s module response?

I have tried several examples around the web but none of them appear to work.

request(         


        

Answer 1

Like @Iftah said, set encoding: null.

Full example (less error handling):

request = require('request');
zlib = require('zlib');

request(url, {encoding: null}, function(err, response, body){
    if(response.headers['content-encoding'] == 'gzip'){
        zlib.gunzip(body, function(err, dezipped) {
            callback(dezipped.toString());
        });
    } else {
        callback(body);
    }
});

Answer 2

I couldn't get request to work either, so ended up using http instead.

var http = require("http"),
    zlib = require("zlib");

function getGzipped(url, callback) {
    // buffer to store the streamed decompression
    var buffer = [];

    http.get(url, function(res) {
        // pipe the response into the gunzip to decompress
        var gunzip = zlib.createGunzip();            
        res.pipe(gunzip);

        gunzip.on('data', function(data) {
            // decompression chunk ready, add it to the buffer
            buffer.push(data.toString())

        }).on("end", function() {
            // response and decompression complete, join the buffer and return
            callback(null, buffer.join("")); 

        }).on("error", function(e) {
            callback(e);
        })
    }).on('error', function(e) {
        callback(e)
    });
}

getGzipped(url, function(err, data) {
   console.log(data);
});

Answer 3

As seen in https://gist.github.com/miguelmota/9946206:

Both request and request-promise handle it out of the box as of Dec 2017:

var request = require('request')
  request(
    { method: 'GET'
    , uri: 'http://www.google.com'
    , gzip: true
    }
  , function (error, response, body) {
      // body is the decompressed response body
      console.log('server encoded the data as: ' + (response.headers['content-encoding'] || 'identity'))
      console.log('the decoded data is: ' + body)
    }
  )

Answer 4

Here is my two cents worth. I had the same problem and found a cool library called concat-stream:

let request = require('request');
const zlib = require('zlib');
const concat = require('concat-stream');

request(url)
  .pipe(zlib.createGunzip())
  .pipe(concat(stringBuffer => {
    console.log(stringBuffer.toString());
  }));

Answer 5

With got, a request alternative, you can simply do:

got(url).then(response => {
    console.log(response.body);
});

Decompression is handled automagically when needed.

Answer 6

I have formulated a more complete answer after trying the different ways to gunzip, and solving errors to do with encoding.

Hope this helps you too:

var request = require('request');
var zlib = require('zlib');

var options = {
  url: 'http://some.endpoint.com/api/',
  headers: {
    'X-some-headers'  : 'Some headers',
    'Accept-Encoding' : 'gzip, deflate',
  },
  encoding: null
};

request.get(options, function (error, response, body) {

  if (!error && response.statusCode == 200) {
    // If response is gzip, unzip first
    var encoding = response.headers['content-encoding']
    if (encoding && encoding.indexOf('gzip') >= 0) {
      zlib.gunzip(body, function(err, dezipped) {
        var json_string = dezipped.toString('utf-8');
        var json = JSON.parse(json_string);
        // Process the json..
      });
    } else {
      // Response is not gzipped
    }
  }

});