Convert BBCODE and smiles to HTML

Php-mysql Course

This tutorial shows you a simple PHP function easy to use to convert BBCODE tags ([b], [i], [u], [block], [color], [br], [url], [img]), and character sets used for "smiles" (like: ":)", ":(", ":P", ":O", ...) to HTML.
Here is the technique:
We create two arrays inside a function, an array with regexp format for each BBCODE tag and smile-characters, and another array with HTML tags corresponding to each BBCODE, in the same order.
The function receives a string as parameter, using preg_replace(), the BBCODE tags from the first array are converted to the corresponding HTML tag defined in the second array.
- In the code bellow, under this function there is an example for test.

PHP function to convert BBCODE and smiles to HTML

<?php
// function to convert bbcode, and smiles to html
function bbcodeHtml($str) {
  // delete 'http://' because will be added when convert the code
  $str = str_replace('[url=http://', '[url=', $str);
  $str = str_replace('[url]http://', '[url]', $str);

  // Array with RegExp to recognize the code that must be converted
  $bbcode_smiles = array(
    // RegExp for [b]...[/b], [i]...[/i], [u]...[/u], [block]...[/block], [color=code]...[/color], [br]
    '/\[b\](.*?)\[\/b\]/is',
    '/\[i\](.*?)\[\/i\]/is',
    '/\[u\](.*?)\[\/u\]/is',
    '/\[block\](.*?)\[\/block\]/is',
    '/\[color=(.*?)\](.*?)\[\/color\]/is',
    '/\[br\]/is',

    // RegExp for [url=link_address]..link_name..[/url], or [url]..link_address..[/url]
    '/\[url\=(.*?)\](.*?)\[\/url\]/is',
    '/\[url\](.*?)\[\/url\]/is',

    // RegExp for [img=image_address]..image_title[/img], or [img]..image_address..[/img]
    '/\[img\=(.*?)\](.*?)\[\/img\]/is',
    '/\[img\](.*?)\[\/img\]/is',

    // RegExp for sets of characters for smiles: :), :(, :P, :P, ...
    '/:\)/i', '/:\(/i', '/:P/i', '/:S/i', '/:O/i', '/=D\>/i', '/\>:D\</i', '/:D/i', '/:-\*/i'
  );

  // Array with HTML that will replace the bbcode tags, defined inthe same order
  $html_tags = array(
    // <b>...</b>, <i>...</i>, <u>...</u>, <blockquote>...</blockquote>, <span>...</span>, <br/>
    '<b>$1</b>',
    '<i>$1</i>',
    '<u>$1</u>',
    '<blockquote>$1</blockquote>',
    '<span style="color:$1;">$2</span>',
    '<br/>',

    // a href...>...</a>, and <img />
    '<a target="_blank" href="http://$1">$2</a>',
    '<a target="_blank" href="http://$1">$1</a>',
    '<img src="$1" alt="$2" />',
    '<img src="$1" alt="$1" />',

    // The HTML to replace smiles. Here you must add the address of the images with smiles
    '<img src="icos/1.gif" alt=":)" border="0" />',
    '<img src="icos/2.gif" alt=":(" border="0" />',
    '<img src="icos/3.gif" alt=":P" border="0" />',
    '<img src="icos/4.gif" alt=":S" border="0" />',
    '<img src="icos/5.gif" alt=":O" border="0" />',
    '<img src="icos/6.gif" alt="=D&gt;" border="0" />',
    '<img src="icos/7.gif" alt="&gt;: D&lt;" border="0" />',
    '<img src="icos/8.gif" alt=": D" border="0" />',
    '<img src="icos/9.gif" alt=":-*" border="0" />'
  );

  // replace the bbcode
  $str = preg_replace($bbcode_smiles, $html_tags, $str);

  return $str;
}

// Test
$str = 'Test [b]PHP tutorials[/b].[br]
[i][color=blue]Blue, and oblique string[/color][/i], underlined: [u]BBCODE tags[/u][br]
Link: [url=https://coursesweb.net/php-mysql/]PHP Course[/url], smiles: =D>, :), >:D< ...
[block]Text added in "block", for blockquote[/block]
An image: [img=https://coursesweb.net/imgs/webcourses.gif]Course Web[/img]';

echo bbcodeHtml($str);
?>

Test PHP tutorials.
Blue, and oblique string, underlined: BBCODE tags
Link: PHP Course, smiles: , , ...

Text added in "block", for blockquote

An image: