JSON Zip Response in node.js

Question

I\'m pretty new to node.js and I\'m trying to send back a zip file containing JSON results. I\'ve been trying to figure it out how to do it, but haven\'t had the expected result

Answer 1

For Express 4+, compress does not come bundled with Express and needs to be installed separately.

$ npm install compression

Then to use the library:

var compression = require('compression');
app.use(compression());

There are a bunch of options you can tune, see here for the list.

Answer 2

You can compress output in express 3 with this:

app.configure(function(){
  //....
  app.use(express.compress());
});


app.get('/foo', function(req, res, next){
  res.send(json_data);
});

If the user agent supports gzip it will gzip it for you automatically.

Answer 3

I think you mean how do I send Gzip content with node?

Node version 0.6 and above have a built in zlip module, so there is no need to require external modules.

You can send Gzip content like this.

 response.writeHead(200, { 'content-encoding': 'gzip' });
    json.pipe(zlib.createGzip()).pipe(response);

Obviously you will need to first check weather the client accepts the Gzip encoding and also remember gzip is a expensive operation so you should cache the results.

Here is full example taking from the docs

// server example
// Running a gzip operation on every request is quite expensive.
// It would be much more efficient to cache the compressed buffer.
var zlib = require('zlib');
var http = require('http');
var fs = require('fs');
http.createServer(function(request, response) {
  var raw = fs.createReadStream('index.html');
  var acceptEncoding = request.headers['accept-encoding'];
  if (!acceptEncoding) {
    acceptEncoding = '';
  }

  // Note: this is not a conformant accept-encoding parser.
  // See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
  if (acceptEncoding.match(/\bdeflate\b/)) {
    response.writeHead(200, { 'content-encoding': 'deflate' });
    raw.pipe(zlib.createDeflate()).pipe(response);
  } else if (acceptEncoding.match(/\bgzip\b/)) {
    response.writeHead(200, { 'content-encoding': 'gzip' });
    raw.pipe(zlib.createGzip()).pipe(response);
  } else {
    response.writeHead(200, {});
    raw.pipe(response);
  }
}).listen(1337);