How To make a tag cloud using PHP and CSS

Category: php

Date: August 2020
Views: 3.15K

A Tag cloud is a section of your website that shows a cluster of words that are different in size according to how many times they appear in your website. for example if the words are wallpapers tags, then they would show the most tagged wallpapers in your database and this is the example I am going to use in this article.
My "Wallpapers" Database consists of 3 tables:

    wallpaperstable (id,url,resolution,x,y,views,dateadded)
    tagstable(id,tagname,tagtext)
    wallpaperstags(id,tagid)

The only tables that consern us in this article are tagstable and wallpaperstags . As you might have guessed it, the second table represents a wallpaper-id, tag-id combination. A wallpaper can have multiple different tags. it is a one to many relationship. we will count how many times a tagid is repeated by joining them and grouping the colmuns by the tagid and counting them with count(tagid) with the following sql query:


SELECT tagname , count(tagid) as weight from wallpaperstags t1
JOIN tagstable t2 on t1.tagid = t2.id
group by tagid  order by weight desc limit :limit

The number of times a tagid is repeated in wallpaperstags will be the weight of the tag and later will be used to decide its font-size in the cloud we are creating.

Here is the full code for the tag cloud:


<!doctype html>
<?php

$host = "localhost";
$user = "root";
$password = "1313";

$pdo = new PDO("mysql:host=$host", $user, $password);
$pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE,PDO::FETCH_ASSOC);
$pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);

$pdo->query("use Wallpapers");

$limit = 30;
$query = "  SELECT tagname , count(tagid) as weight from wallpaperstags t1
	JOIN tagstable t2 on t1.tagid = t2.id
	group by tagid  order by weight desc limit :limit";
$sql = $pdo->prepare($query);
$sql->bindValue(':limit', (int) $limit, PDO::PARAM_INT);
$sql->execute();
$tags = $sql->fetchAll();

$keys = array_keys($tags);
shuffle($keys);
foreach($keys as $key){
	$new[$key] = $tags[$key];
}
$tags = $new;



?>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
        <link rel="stylesheet"
              href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css"
              integrity="sha384-GJzZqFGwb1QTTN6wy59ffF1BuGJpLSa9DkKMp0DgiMDm4iYMj70gZWKYbI706tWS"
              crossorigin="anonymous">
        <title></title>

		<style>
				.cloud-div {
						width:50%;
						justify-content:center;
						text-align:center;
				}
				.cloud-tag {
					padding: 0;
					padding-right: 5px;
					vertical-align:center;
					white-space: nowrap;
				}
		</style>
    </head>
    <body>
        <div class="container-fluid">
<?php
$starting_font_size = 10;
$factor = 0.4;
echo '<div class="cloud-div">';
foreach ($tags as $t) {
	$x = round( $t["weight"]/100) * $factor;
	$font_size = $starting_font_size + $x.'px';
	echo '<a href="#">
		<span class="cloud-tag" style="font-size: '.$font_size.';">'
		.$t["tagname"].'
		</span>
		</a>';
}
echo '</div>';
 ?>
        </div>
        <script
            src="https://code.jquery.com/jquery-3.3.1.js"
            integrity="sha256-2Kok7MbOyxpgUVvAk/HJ2jigOSYS2auK4Pfzbm7uH60="
            crossorigin="anonymous"></script>
        <script
            src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"
            integrity="sha384-wHAiFfRlMFy6i5SRaxvfOCifBUQy1xHdJ/yoi7FRNXMRBu5WHdZYu1hA6ZOblgut"
            crossorigin="anonymous"></script>
        <script
            src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js"
            integrity="sha384-B0UglyR+jN6CkvvICOB2joaf5I4l3gm9GU6Hc1og6Ls7i6U/mkkaduKaBhlAXv9k"
            crossorigin="anonymous"></script>
    </body>
</html>

In the following video, I show the step by step process of writing this code and explain every part of it.