core streams in node

many of the APIs in node core provide stream interfaces:

• fs.createReadStream()
• fs.createWriteStream()
• process.stdin, process.stderr ☛ stderr (you can put errors in the terminal)
• ps.stdin, ps.stdout, ps.stderr
• net.connect(), tls.connect()
• net.createServer(function (stream) {})
• tls.createServer(opts, function (stream) {}) ☛ for ssl connections (you need certificates)

...

You can create child processes in NodeJS.

  //	****		ps.js		****
var spawn = require('child_process').spawn

var ps = spawn('grep', ['potato'])
ps.stdout.pipe(process.stdout)
ps.stdin.write('chees\n')
ps.stdin.write('carrot\n')
ps.stdin.write('carrot potatoes\n')
ps.stdin.write('potato!\n')
ps.stdin.end()

So every time on this child process, I put the string "potato" it will return it.

Now, $ node ps.js returns:

carrot potatoes
potato!

http core streams

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

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