PHP: handle undefined exception

Question

I have a device that sends data to url, depending on situations 3 sometimes 4 parameters are received, when i try to get data for 4th parameter using

$a = $_GET["xyz"];

in the case when "xyz" does not exist the function

_GET['xyz'];

returns undefined. i tried using try catch and initialized $a to a empty string in catch part but it did not work either. How can that undefined exception be handled?

http://stackoverflow.com/a/4261200/998096 – Ofir Baruch May 12 '15 at 10:25 — Ofir Baruch, May 12 '15 at 10:25

score 2 · Accepted Answer · answered May 12 '15 at 10:26

2

isset

  if(isset($_GET["xyz"])) {
        $a = $_GET["xyz"];
  }

answered May 12 '15 at 10:26

smarber

4,829
7
37
78

score 1 · Answer 2 · answered May 12 '15 at 10:25

If you want to check if a parameter is passed in through the URL, you can use isset()

http://php.net/manual/en/function.isset.php

This will check to see if the parameter exists

// This will evaluate to TRUE so the text will be printed.
if (isset($var)) {
    echo "This var is set so I will print.";
}

score 1 · Answer 3 · answered May 12 '15 at 10:26

1

You can use ternary operator

$a=(isset($_GET["xyz"]))?$_GET["xyz"]:'';

answered May 12 '15 at 10:26

Pranay Aher

444
4
11

score 1 · Answer 4 · answered May 12 '15 at 10:29

To handle such errors, you should use php's library function,

set_error_handler

On having error such as undefined index, undefined variable etc.. will be handle by handleError function.

public function handleError($code,$message,$file,$line){
    // handling 
}

All the Best !!

PHP: handle undefined exception

4 Answers4