Before running, install express by running npm install express and run with: node absurd_rest_service.js in this script's directory. Then: To submit calculation to curl -i -H "Content-Type: application/json" -d '{ "operation" : "+", "operands" : [ 2,3] }' http://localhost:3000/calculations To see results, use link from response: curl http://loca…

absurd_rest_service.js

/*
  Before running, install express by running

  npm install express
  
  and run with:
  
  node absurd_rest_service.js

  in this script's directory.
  Then:

  To submit calculation to 
  curl -i -H "Content-Type: application/json" -d '{ "operation" : "+", "operands" : [ 2,3]   }' http://localhost:3000/calculations

  curl http://localhost:3000/results/1

 */
var express = require('express');
var events = require('events');

var app = express();
app.use(express.bodyParser());

var sequence = 0;   // poor man's sequence
var results = [];

function execute(operation) {
    if (operation.operation === '+') {
        return operation.operands[0] + operation.operands[1];
    } else if (operation.operation === '*') {
        return operation.operands[0] * operation.operands[1];
    }
}

app.post('/calculations', function (req, res) {
    res.setHeader('Content-Type', 'application/json');
    sequence++;
    results[sequence] = execute(req.body);
    res.status(202);
    res.json({ outcome: "success", links: { result: "http://localhost:3000/results/" + sequence }  });
});

app.get('/results/:id', function (req, res) {
    res.setHeader('Content-Type', 'application/json');
    res.json({ result: results[req.params['id']] });
});

app.listen(3000);
console.log("App listening on port 3000");