Server Side Scripting With NodeJS

Start Node Server

Download node, create a new nodejs project and install express, bodyparser.

Express JS server

const express = require('express')
const bodyParser = require('body-parser')

const app = express()

app.use(bodyParser.json())

app.get('/addfive/:int', (req,res)=> {
    const integer = req.params.int
    res.send(\`Sum:::${parseInt(integer) + 5}\`)
})

app.listen(5000, () => console.log(\`App Running on port 5000 ::::\`))

Create A Express Application

Import Express and create a new express application:

//Import Express
const express = require('express');

//Create Express App
const app = express();

Body Parser

Body parser is a package that parses incoming request stream and makes in available under the req.body property.

//Import body-parser
const bodyParser = require('body-parser');

//Use body-parser middleware
app.use(bodyParser.json());  // parse application/json

It is important to note that body parser middleware should be used before the actual route handlers.

Route Handler

app.get('/addfive/:int', (req,res)=> {
    const integer = req.params.int
    res.send(\`Sum:::${parseInt(integer) + 5}\`)
});


I have defined a simple route handler which will handle GET request at “{base_url}/addfive/{integer_user_input}” .

Every time a request is made, integer 5 is added to the incoming user input (integer that will come after /addfive/ , example: /addfive/5 will return 10 as sum) and output is set as response in JSON format.

Running The Application

app.listen(5000, () => console.log(\`App Running on port 5000 ::::\`))

This is how we run an express application on a specific port.

XRequest

XRequest will allow user to make requests to the express application from the console.

<Resource xmlns="http://xml.metamug.net/resource/1.0" v="1.0">
  <Request method="GET">
     <XRequest id="1" url="http://localhost:5000/addfive/14"
                       method="GET" output="true">              
     </XRequest>
  </Request>
</Resource>

The above XML resource represents a sample XRequest from console to the node application running on port 5000. We specify output=”true” to see the output in JSON format.

Output

{
  "1": {
    "sum": 19
  }
}

Refer XRequest Documentatation for more information.

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