php Dynamic page

Question

I'm not sure if the title here is appropriate and my explanation might be just as bad but here it goes... I am using the following code to generate web pages:
source: Dynamic inclusion in PHP

<?php

$id = $_GET['id']; 

$display = $_GET['display'];
    $displays = array('page1', 'page2', 'page3', 'page4', 'page5&amp;id=$id');

if (!empty($display)) {
        if(in_array($display,$displays)) {
            $display .= '.php';
            include($display);
        }
        else {
        echo 'Page not found. Return to
        <a href="index.php">Index</a>';
        }
    }
    else { //show html

?>

a typical page:

My problem is this: I want to add a page to the array of allowed pages that has a dynamic value. You can see my attempt at this in the code above where i added: 'page5&id=$id'

However when i go to this page:

I get the error message "Page not found. Return to Index". (The table row id with value of 2 does exist in the database.)

Answer 1

You should better handle the display and ID values separately. For example like this:

<?php

$display = $_GET['display'];
$displays = array('page1', 'page2', 'page3', 'page4', 'page5');

if (!empty($display)) {
        if(in_array($display,$displays)) {
            $display .= '.php';
            include($display);
        }
        else {
        echo 'Page not found. Return to
        <a href="index.php">Index</a>';
        }
    }
    else { //show html

?>

and in display5.php:

 <?php

 // some other initializations

 $id = $_GET['id'];
 if($id == 2) { // make some special actions for id = 2

 // show more html
 ?>

Answer 2

Just like you will receive a value in $_GET['display'] , you will receive another in $_GET['id'] with a value of 2 !

PHP separates them from the query string. When you use in_array() , you'll check whether page5 is in $displays , as you can see from your code, it's not.

I suggest you use var_dump($_GET); and then look at the source of the produced HTML to see how GET parameters are being handled.

Answer 3

Thats why in $_GET["display"] stands only "page5" and in $_GET["id"] the 2. You can check the ID in the page5.php.

For example in page5:

<? if (empty($_GET["id"]) || !is_numeric($_GET["id"])) { die("ID isn't a number!"); } ?>