Need some PHP assistance - php

Question

how do i tell this php code that, when there's not a ?page=randompage in the url, it will trow the active to index.php automatically?
<?php
$query = "SELECT pagename, pagetitle FROM pages LIMIT 8";
$result = $mysqli->query($query);
echo "<ul>";
while ($row = $result->fetch_array(MYSQLI_ASSOC)){
echo "<li><a href=\"?page=".$row["pagename"]."\"";
if ($_GET['page'] == $row['pagename']) {
echo " class=\"active\""; } echo "> ".$row["pagetitle"]." </a></li>";
}
echo "</ul>";
?>
It's beacuse whenever my url looks like this http://localhost/greencph/ it shows a php error, because it does not know which site it is on, it works perfect as long as the url looks like this: http://localhost/greencph/?page=index.php a detailed explanation on how to fix this problem would be appreciated!
Please remember i'm a idiot, explain to me so i understand it. xD

Answer 1

The error is coming because, every time the value of $_GET is not getting set.
So, to deal with it,
get the value of $_GET['page'] in a variable.
So that, if we do not get $_GET, we will assign it a default value, that is index page.
$page = ! empty($_GET['page']) ? $_GET['page'] : 'index'; // set default value.
And change this line:
if ($page == $row['pagename']) {
So, the final modified code should be:
<?php
$query = "SELECT pagename, pagetitle FROM pages LIMIT 8";
$result = $mysqli->query($query);
$page = ! empty($_GET['page']) ? $_GET['page'] : 'index';
echo '<ul>';
while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
$class = '';
if ($page == $row['pagename']) {
$class = 'active';
}
echo '<li>' . $row["pagetitle"].' </li>';
}
echo "</ul>";
?>

Answer 2

Use the $_GET array:
<?php
if(isset($_GET['page'])) {
// Your code
...
}
?>

Answer 3

Problem is in this line
if ($_GET['page'] == $row['pagename']) {
You're not checking whether the index 'page' even exists. So, when you try to load the page without any GET parameters $_GET['page'] won't be even set and you'll get an error for accessing unset element.
To fix this simply check
if(isset($_GET['page']) {
...your code...
}