PHP Switch ID error in Navigation

Question

Hey guys,

I’m working on a site and I kept getting a

Notice: Undefined index: id in file root on line 3

I know its something simple but can’t figure out where the problem lies exactly.

here is the code:

<?php
    switch($_GET['id']) {
        default:
            include('pages/hello.php');
        break;
        case "testimonials": 
            include('pages/testimonials.php');
        break;
        case "faq":
            include('pages/faq.php');
        break;
        case "raq":
            include('pages/raq.php');
        break;
        case "contact":
            include('pages/contact.php');
        break;
    }
?>

line 3 would be <?php switch($_GET['id']) {

any help would be greatly appreciated!

Answer 1

It seems that the url parameter 'id' is not defined, that's the cause of the notice.

You should first check for its existence, eg.

if (isset($_GET['id'])) {
  your code here
}

Answer 2

Make sure that id is set and the default should go at the end:

if (!isset($_GET['id'])) {
  include('pages/hello.php');
}
else{
  switch($_GET['id']) {
    case "testimonials": include('pages/testimonials.php'); break;
    case "faq": include('pages/faq.php'); break;
    case "raq": include('pages/raq.php'); break;
    case "contact": include('pages/contact.php'); break;
    default: include('pages/hello.php'); break;
  }
}

For security reasons, make sure to sanitalize yor $_GET['id']. I would suggest you to setup an array of allowed pages and include those that are in the array. You can use in_array function for that.

Answer 3

This is because in your url id=x is not always set, so when your trying to switc hthe value its not there. what you should do is like so:

<?php

    $id = isset($_GET['id']) ? $_GET['id'] : ''; //This is just  a short if-else
    switch($id)
    {
        default:
            include('pages/hello.php');
        break;
        case "testimonials": 
            include('pages/testimonials.php');
        break;
        case "faq":
            include('pages/faq.php');
        break;
        case "raq":
            include('pages/raq.php');
        break;
        case "contact":
            include('pages/contact.php');
        break;
    }
?>

Basciall $id = isset($_GET['id']) ? $_GET['id'] : ''; what this says is, IF id is within the url then use that, otherwise use an empty string, the reason for the empty string is it will trigger the default: within the switch statement

this way $id will always be set to something.