How to limit response length with http.request in Node.js

Question

So in this (simplified) bit of code, when someone hits my node server I make a GET request to another website and print the HTML page title to the console. Works fine:

var http = require("http");
var cheerio = require('cheerio');

var port = 8081;
s = http.createServer(function (req, res) {
var opts = {
    method: 'GET',
    port: 80,
    hostname: "pwoing.com",
    path: "/"
};
http.request(opts, function(response) {
    console.log("Content-length: ", response.headers['content-length']);
    var str = '';
    response.on('data', function (chunk) {
        str += chunk;
    });
    response.on('end', function() {
        dom = cheerio.load(str);
        var title = dom('title');
        console.log("PAGE TITLE: ",title.html());
    });
}).end();
res.end("Done.");
}).listen(port, '127.0.0.1');

However, in the actual app, users can specify a URL to hit. That means my node server could be downloading 20GB movie files or whatever. Not good. The content-length header is no use for stopping this either as it isn't transmitted by all servers. The question then:

How can I tell it to stop the GET request after, say, the first 10KB are received?

Cheers!

Answer 1

You could abort the request once you have read enough data:

  http.request(opts, function(response) {
    var request = this;
    console.log("Content-length: ", response.headers['content-length']);
    var str = '';
    response.on('data', function (chunk) {
      str += chunk;
      if (str.length > 10000)
      {
        request.abort();
      }
    });
    response.on('end', function() {
      console.log('done', str.length);
      ...
    });
  }).end();

This will abort the request at around 10.000 bytes, since the data arrives in chunks of various sizes.