http core streams

When using createServer the req object is readeable, while the res is writable (not full duplex).

// req: readable, res: writable
http.createServer(function (req, res) {})

// req: writable, res: readable
var req = http.request(opts, function (res) {})

When using the request module, it's the opposite, the request (req) becomes writable and the res is readable.

---

http

var http = require('http')
var server = http.createServer(function (req, res) {
  req.pipe(process.stdout)
  res.end('hello thar!\n')
})
server.listen(5000)

---

We will create a server, that pipes the contents of a file into a res object. There are of course lots of better npm modules to serve up static files.

  //	****		http.js		****

var http = require('http')
const fs = require('fs')

var server = http.createServer(function (req, res) {
  if (req.method === 'POST') {
    req.pipe(process.stdout)
    req.once('end', function () {
      res.end('ok\n')
    }) else {
      // the branch where we are reading from the file
      // set the headers
      res.setHeader('content-type', 'text/plain')
      fs.createReadStream('hello.txt').pipe(res)
    }
  }
})

// start listening
server.listen(5000)

Then write the client:

  //	****		http-client.js		****

var http = require('http')

// first, we make a POST request ↴
var req = http.request({ 
  method: 'POST', 
  // the correct way to specify the url `http://localhost:5000/`
  // with req
  host: 'localhost'
  path: '/',
  port: '5000'
}, 
  function(res) {
    console.log(res.statusCode)
    res.pipe(process.stdout)
})


// req.write() ☛ req.end is a also a shortcut for req.write()
req.end('HELLO\n')

With this, our server will just dump the request to stdout.

Now $ node http-client.js will print

200
ok

and on the server ($ node http.js):

HELLO

Now, try to get the file.

  //	****		http-get-client.js		****

var http = require('http')
var req = http.request({
  method: 'GET',
  host: 'localhost',
  port: 5000,
  path: '/'
}, function (res) {
  console.log(res.statusCode)
  res.pipe(process.stdout)
})
// we do need to end the request
// even though this is a get request
req.end()