Nodejs send data in gzip using zlib - node.js

Question

I tried to send the text in gzip, but I don't know how. In the examples the code uses fs, but I don't want to send a text file, just a string.
const zlib = require('zlib');
const http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/html', 'Content-Encoding': 'gzip'});
const text = "Hello World!";
res.end(text);
}).listen(80);

Answer 1

You're half way there. I can heartily agree that the documentation isn't quite up to snuff on how to do this;
const zlib = require('zlib');
const http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/html', 'Content-Encoding': 'gzip'});
const text = "Hello World!";
const buf = new Buffer(text, 'utf-8'); // Choose encoding for the string.
zlib.gzip(buf, function (_, result) { // The callback will give you the
res.end(result); // result, so just send it.
});
}).listen(80);
A simplification would be not to use the Buffer;
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/html', 'Content-Encoding': 'gzip'});
const text = "Hello World!";
zlib.gzip(text, function (_, result) { // The callback will give you the
res.end(result); // result, so just send it.
});
}).listen(80);
...and it seems to send UTF-8 by default. However, I personally prefer to walk on the safe side when there is no default behavior that makes more sense than others and I can't immediately confirm it with documentation.
Similarly, in case you need to pass a JSON object instead:
const data = {'hello':'swateek!'}
res.writeHead(200, {'Content-Type': 'application/json', 'Content-Encoding': 'gzip'});
const buf = new Buffer(JSON.stringify(data), 'utf-8');
zlib.gzip(buf, function (_, result) {
res.end(result);
});