Echo everything back to the request sender.

commands.sh

# Install Node.js.
curl -L http://git.io/n-install | bash

# Restart the shell or execute shell profile.

# Install dependency.
npm install koa co-body

test-echo-server.js

const koa    = require('koa'),
      coBody = require('co-body'),
      app    = koa();

app.use(function *() {
  this.body = {
    headers: this.headers,
    body   : ['POST', 'PUT'].indexOf(this.req.method) >= 0 && (yield coBody(this)) || 'Empty',
    query  : this.query
  };
});

app.listen(30000);