In one of the project where I've worked on, we had the requirement of showing some live data graphs, where the input data were coming through a Streaming http.
The customer wanted to see the data real time with max 1 second delay, and doing some calculations we've came out that using a server process for this would have not match the customer expectations, then we decided to go for a Client side approach using JavaScript.
This is why I discovered this easy and nice solution which worked very well and which met all the customer requirements. Here is the result:
The graphs were getting updated in real time thanks to:
- On ready state change event, which was getting the streaming update and enqueue the values:
http://www.w3schools.com/ajax/ajax_xmlhttprequest_onreadystatechange.asp
- The Chart Library which has been used to show the Graph:
http://www.flotcharts.org/
Here is the snippet used to get the Streaming update:
<!DOCTYPE html>
<html>
<head>
<script>
function loadXMLDoc()
{
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==3 && xmlhttp.status==200)
{
document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","http://<Some HOST and PORT>/<STREAMING URL>",true);
xmlhttp.send();
}
</script>
</head>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2></div>
<button type="button" onclick="loadXMLDoc()">Change Content</button>
</body>
</html>
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