Tag: GET Method

Network I/O Is Unpredictable: Node.js

We’ve seen the importance of callback method in our previous video tutorials. Now lets see how networked I/O Is unpredictable.


http-module-get-method-nodejs-network-io-unpredictability

Here we request/ping for information from 3 different servers and look at its response time. Each time we send a request, we get different response time depending upon how busy the server is, its bandwidth etc.

JavaScript File
app.js

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var http= require("http"),
      urls  = [ "technotip.org",
         "technotip.com",
      "www.capturecaption.com"
       ];
 
for(var i = 0; i < urls.length; i++){
ping( urls[i] );
}
 
function ping( url ){
var start = new Date();
 
http.get({ host: url }, function(res){
console.log("URL :"+url);
console.log("Response Time: "+(new Date() - start)+" ms");
});
}

Here we require http module, which is built into nodejs, and store it inside a local object called http. We also declare and initialize an array with 3 domain names. Using for loop, we loop through each URL present in the urls array and pass it to a method called ping();

Inside ping method, we record client system date in a variable before sending a request to the server(via URL). Now using http objects get method we send request to the server and see it’s response time. get method takes 2 parameter, first parameter is an object which contains host information – the host url { host: url }. Second parameter is a callback method which automatically gets an object which is returned by first parameter {host: url}. Inside the callback method, we subtract the new system date with the one we recorded before requesting for a response, this way we calculate the response time of each URL.

HTTP get method: Node.js


[youtube https://www.youtube.com/watch?v=vktKMtWoPbA]

YouTube Link: https://www.youtube.com/watch?v=vktKMtWoPbA [Watch the Video In Full Screen.]



output
C:\node>node app.js
URL :technotip.com
Response Time: 1462 ms
URL :www.capturecaption.com
Response Time: 1993 ms
URL :technotip.org
Response Time: 2004 ms

C:\node>node app.js
URL :technotip.com
Response Time: 1381 ms
URL :www.capturecaption.com
Response Time: 1702 ms
URL :technotip.org
Response Time: 1871 ms

C:\node>node app.js
URL :technotip.com
Response Time: 1409 ms
URL :www.capturecaption.com
Response Time: 1628 ms
URL :technotip.org
Response Time: 2001 ms

C:\node>node app.js
URL :technotip.com
Response Time: 1512 ms
URL :www.capturecaption.com
Response Time: 1534 ms
URL :technotip.org
Response Time: 1899 ms

Each time we execute the script, we get different response time, and the order of URLs may also differ, as we can’t predict which server will respond first.

GET Method In Action: Simple Form

This Basic PHP tutorial illustrates the usage of GET method, with the help of a simple HTML form. It echo’s/print’s the user entered information on to the browser by passing it via GET method.
It also tells one big advantage of GET method over POST method.

Source Code
We have purposefully kept this example super simple, as this is a basic thing in PHP and complex things may confuse beginners.

Source Code: GET Method In Action: Simple Form

getForm.php

<html>
 <head><title>Form using GET method</title></head>
 <body>
<form action="get.php" method="get">
Name <input type="text" name="uname"><br />
Age    <input type="text" name="age"><br />
<input type="submit" value="Submit Info">
</form>
 </body>
</html>

This is a simple form which contains 2 input fields and a submit button. Observe the method used: its GET method.
We have given unique name to each input fields, so that the values are passed to the get.php

get.php

<?php
 
$name = $_GET['uname'];
$age     = $_GET['age'];
 
echo "Name is $name <br /> Age is $age";
 
?>

This is the actual file where the action takes place. All the information is passed on to this file via getForm.php file. Using $_GET[] we receive the values and store it in the local variables. Using the values in these local variables we can do whatever we want to do: like print it on the browser(as we do in this tutorial), insert it into database etc.

Video Tutorial: GET Method In Action: Simple Form


[youtube https://www.youtube.com/watch?v=3zmH6zXyrx8]

YouTube Link: https://www.youtube.com/embed/3zmH6zXyrx8 [Watch the Video In Full Screen + HD]


Advantages of using GET method over POST method

One of the biggest advantage of using GET method is, we can send the URL in the address bar to a friend over email as it contains the name and associated value in the URL. But in post method, you will neither get the name nor the value in the address bar, hence you can’t send it over to any one. If you still send, it may not make any sense!

Ex: You Google for the term “technotip”. Copy the URL in the address bar and can send it to your friend. Many bookmarking sites use GET method, because users must be able to copy and paste the url and pass it on to their friends. If they used POST method, then its of no use to send the url, since the URL before and after querying remains same!