12. HTTP UPPERCASERER

HTTP UPPERCASERER (Exercise 12 of 13)

Write an HTTP server that receives only POST requests and converts
incoming POST body characters to upper-case and returns it to the client.

Your server should listen on the port provided by the first argument to
your program.

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HINTS

While you're not restricted to using the streaming capabilities of the
request and response objects, it will be much easier if you do.

There are a number of different packages in npm that you can use to
"transform" stream data as it's passing through. For this exercise the
through2-map package offers the simplest API.

through2-map allows you to create a transform stream using only a single
function that takes a chunk of data and returns a chunk of data. It's
designed to work much like Array#map() but for streams:

 var map = require('through2-map')  
 inStream.pipe(map(function (chunk) {  
   return chunk.toString().split('').reverse().join('')  
 })).pipe(outStream)  

In the above example, the incoming data from inStream is converted to a
String (if it isn't already), the characters are reversed and the result
is passed through to outStream. So we've made a chunk character reverser!
Remember though that the chunk size is determined up-stream and you have
little control over it for incoming data.

To install through2-map type:

 $ npm install through2-map  

If you don't have an Internet connection, simply make a node_modules
directory and copy the entire directory for the module you want to use
from inside the learnyounode installation directory:

file:///home/ubuntu/.nvm/versions/node/v6.11.2/lib/node_modules/learnyouno
de/node_modules/through2-map

Documentation for through2-map has been installed along with learnyounode
on your system and you can read them by pointing your browser here:

file:///home/ubuntu/.nvm/versions/node/v6.11.2/lib/node_modules/learnyouno
de/docs/through2-map.html

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HTTP UPPERCASERER (Exercise 12 of 13)

//////////////////////////////////////////////
/*  function exercise 12  Uppercaserer      */
//////////////////////////////////////////////


function httpUPPER(){
    
    var http = require('http'); // load networking module
    var port = process.argv[2]; // get the port number from args

    var map = require('through2-map'); // load map module
    
    var server = http.createServer(function (inStream, outStream) {  
        // socket handling logic 

         inStream.pipe(map(function (chunk) {  
           return chunk.toString().toUpperCase();  
         })).pipe(outStream);

    });  
    
    server.listen(port);     
   
}

    httpUPPER();

Your submission results compared to the expected:

             ACTUAL                                 EXPECTED                

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"TRUCKIE" == "TRUCKIE"
"DOOVALACKY" == "DOOVALACKY"
"SHEILA" == "SHEILA"
"PASH" == "PASH"
"CHOKKIE" == "CHOKKIE"
"LURK" == "LURK"
"TRACKIES" == "TRACKIES"
"GONE WALKABOUT" == "GONE WALKABOUT"
"GALAH" == "GALAH"
"RUBBISH" == "RUBBISH"
"" == ""

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✓

Submission results match expected

PASS Your solution to HTTP UPPERCASERER passed!

Here's the official solution in case you want to compare notes:

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    var http = require('http')
    var map = require('through2-map')
    
    var server = http.createServer(function (req, res) {
      if (req.method !== 'POST') {
        return res.end('send me a POST\n')
      }
    
      req.pipe(map(function (chunk) {
        return chunk.toString().toUpperCase()
      })).pipe(res)
    })
    
    server.listen(Number(process.argv[2]))

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