Creating the main application

The main project contains several files. To best present things, we'll only concentrate on two files:

• server.js: This is the file that will create our web server and send data to the HTML web page

• index.html: This is the page that will open the web browser to display the data received

server.js

The server.js file creates a server on the listening port 3344 and will be responsible for creating a socket (rpi_temperature) that contains the CPU temperature of Raspberry Pi. The socket function uses, among others, the vcgencmd command ( https://github.com/raspberrypi/firmware/blob/master/opt/vc/bin/vcgencmd ), permitting us to monitor the CPU temperature, as shown here:

setInterval(function() 
{ 
    child = exec("vcgencmd measure_temp | awk -F:", function      (error, stdout, stderr)  
    { 
        if (error !== null)  
        { 
            console.log('exec error: ' + error); 
        } 
        else 
        { 
            var date = new Date().getTime(); 
  ...