upload concat response

README.md

Express web app that exposes and upload endpoint.

Upload three files to it. Post successful upload of 3rd file a response is returned to each client

use cURL as client, but not mandatory.

app.js

var Readable = require('stream').Readable;
var fs = require('fs');
var spawn = require('child_process').spawn;

var express = require('express');
var multer = require('multer');

var app = express();
var uploading = multer({});

var files;
var done = false;

app.post('/upload', uploading.single('file'), (req, res) => {
  var readable;
  var push = (item) => {
    readable.push(item.buffer);
    readable.push(new Date().toString() + '\r\n')
  };
  var data;
  if (!files) {
    files = [];
  }
  // console.log(req.file);
  files.push(req.file);

  if (files.length === 3) {
    readable = new Readable;
    files.forEach(push);
    readable.push(null);

    var echo = spawn('node', ['index.js']);
    echo.stdout.setEncoding('utf8');
    echo.stdout.on('readable', () => {
      var whole = echo.stdout.read();
      if (whole) {
        data = whole;
        var json = new Readable;
        json.push(data);
        json.push(null);

        json.pipe(fs.createWriteStream('combined-foo.txt'))
          .on('close', () => {
            done = true;
            fs.createReadStream('combined-foo.txt').pipe(res);
          });
      }
    });

    readable
      .pipe(echo.stdin);

    files = undefined;
  }
  else {
    var tmr = setInterval(() => {
      if (done) {
        clearInterval(tmr);
        fs.createReadStream('combined-foo.txt').pipe(res);
      }
    }, 100);
  }
});

app.listen('8000', (err) => {
  if(!err) {
    console.log('listening on port 8000');
  }
});

//deleting the resultant file if it exists... (on restarting)
fs.exists('combined-foo.txt', (exists) => {
  if (exists) {
    fs.unlink('combined-foo.txt');
  }
});

index.js

const fs = require('fs');
var rl = require('readline');

var stdinput = rl.createInterface({
	input: process.stdin
});
var lines = []
stdinput.on('line', function(line) {
	lines.push(line);
});

stdinput.on('close', () => {
	console.log(JSON.stringify(lines));
});

package.json

{
  "name": "nodejs-console-app1",
  "version": "0.0.0",
  "description": "NodejsConsoleApp1",
  "main": "app.js",
  "author": {
    "name": "Arun_Jayapal",
    "email": ""
  },
  "dependencies": {
    "body-parser": "^1.15.1",
    "express": "^4.13.4",
    "multer": "^1.1.0",
    "stream-multiplexer": "^1.0.2"
  }
}