Automatic Pagination Help Needed

Question

I have this script:

<?php
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles")
{
    include("Articles.php");
}
?>

Which allows me to setup a custom URL for a page. Now, the problem occurs comes when I need URLs like these:

/?articles | Page that contains newest articles which loads when user clicks "< Previous" button
/?articles&1 | Page that contains older articles which loads when user clicks "Next >" button
/?articles&2 | Page that contains older than older articles
/?articles&3 | Page that contains old articles
/?articles&4 | Page that contains old articles
/?articles&5 | Page that contains oldest articles
/?articles&6 | Page that contains oldest articles, also last page in the pagination

And so on. Namely, the code in the script above would be like this:

if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&1")
{
    include("Articles-500.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&2")
{
    include("Articles-499.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&3")
{
    include("Articles-498.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&4")
{
    include("Articles-497.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&5")
{
    include("Articles-496.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&6")
{
    include("Articles-495.php");
}

But each time the page with the newest articles gets filled (contains 10 articles per page) I have to update the script like this:

if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&1")
{
    include("Articles-505.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&1")
{
    include("Articles-504.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&1")
{
    include("Articles-503.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&1")
{
    include("Articles-501.php");
}
if(urldecode($_SERVER['REQUEST_URI']) == "/?articles&1")
{
    include("Articles-500.php");
}

I also need you to tell me how to use it practically in my navigation, id est: <A href="?">Next</A> and <A href="?">Previous</A>

Answer 1

What you can do, in order to have this created dynamically is to use the function glob that can list you all the files in a directory.

So given that you would have the files:

• Articles-1.php
• Articles-2.php
• Articles-3.php
• ...

Now, if your articles are indeed named as above (Articles-1.php and not Articles-001.php) you will face the problem that a simple alphabetical sort won't work.
Indeed, Articles-99.php will always show up earlier than Articles-505.php in a simple alphabetical sort.

But, hopefully, PHP offers us the really neat sorting which is natsort().

This function implements a sort algorithm that orders alphanumeric strings in the way a human being would while maintaining key/value associations. This is described as a "natural ordering". An example of the difference between this algorithm and the regular computer string sorting algorithms (used in sort()) can be seen in the example below.

_{Sorting via natsort() is nicer than my original usort idea, all credit for this idea goes to dılo sürücü's answer.}

Still, we need the sorting to be in a reverse order, and this can be provided using the SORT_NATURAL flag on rsort().

SORT_NATURAL - compare items as strings using "natural ordering" like natsort()

Source: https://www.php.net/manual/en/function.sort.php
_{Credit for the usage of this flag goes to Seh Horng's answer}

// Listing all the articles pages
$articles = glob("Articles-*.php");
// Applying reverse natural sorting, with SORT_NATURAL flag on rsort
rsort($articles, SORT_NATURAL);

/**
 * Extracting the selected page out of the REQUEST_URI, 
 * and transform it an integer
 */
$selectedPage = intval(
  str_replace("/?articles&", "", urldecode($_SERVER['REQUEST_URI']))
);

/**
 * This is a sanity check; 
 * just in case someone tries to access a page that does not exists,
 * like the page 99999999999
 * It also tackles the case when intval fails and returns 0
 * causing the index to be 0 - 1 = -1
 *
 * By the way, doing this check also covers your default behaviour
 * on the URL /?articles
 */
if(array_key_exists($selectedPage - 1, $articles)){

  /** 
   * We need to remove one from the selected page, 
   * remembering an array start at 0 in PHP
   */
  include $articles[$selectedPage - 1];
} else {
  include "Articles.php";
}

This should give you the right include dynamically.