Does Express.js support sending unbuffered progressively flushed responses?

Question

Perl\'s Catalyst framework permitts you to send an progressively flushed response over an open connection. You could for instance use write_fh() on Catalyst::Response. I\'ve

Answer 1

Express is built on the native HTTP module, which means res is an instance of http.ServerResponse, which inherits from the writable stream interface. That said, you can do this:

app.get('/', function(req, res) {
  var stream = fs.createReadStream('./file.csv');
  stream.pipe(res);

  // or use event handlers
  stream.on('data', function(data) {
    res.write(data);
  });

  stream.on('end', function() {
    res.end();
  });
});

The reason you can't use the res.send() method in Express for streams is because it will use res.close() automatically for you.