http_server.js

/**
 In this challenge, write an http server that uses a through stream to write back
 the request stream as upper-cased response data for POST requests.

 Streams aren't just for text files and stdin/stdout. Did you know that http
 request and response objects from node core's `http.createServer()` handler are
 also streams?

 For example, we can stream a file to the response object:

 var http = require('http');
 var fs = require('fs');
 var server = http.createServer(function (req, res) {
        fs.createReadStream('file.txt').pipe(res);
    });
 server.listen(8000);

 This is great because our server can response immediately without buffering
 everything in memory first.

 We can also stream a request to populate a file with data:

 var http = require('http');
 var fs = require('fs');
 var server = http.createServer(function (req, res) {
        if (req.method === 'POST') {
            req.pipe(fs.createWriteStream('post.txt'));
        }
        res.end('beep boop\n');
    });
 server.listen(8000);

 You can test this post server with curl:

 $ echo hack the planet | curl -d@- http://localhost:8000
 beep boop
 $ cat post.txt
 hack the planet

 Your http server should listen on port 8000 and convert the POST request written
 to it to upper-case using the same approach as the TRANSFORM example.

 As a refresher, here's an example with the default through callbacks explicitly
 defined:

 var through = require('through')
 process.stdin.pipe(through(write, end)).pipe(process.stdout);

 function write (buf) { this.queue(buf) }
 function end () { this.queue(null)

Do that, but send upper-case data in your http server in response to POST data.

 */

var http = require('http');
var through = require('through');

var tr = through(function write(data) {
	this.queue(data.toString().toUpperCase());
});

var server = http.createServer(function(req, res) {
	if (req.method == 'POST') {
		req.pipe(tr).pipe(res);
	}
}).listen(8000);