PHP - BBCode parser - Parse both bbcode link tag and not tagged link

Question

Hello to everyone. I need to do this :

when a user insert a BBCode tag, with preg_replace and regex i do some trasformation.

e.g.

function forumBBCode($str){
   $format_search=array(
      '#\[url=(.*?)\](.*?)\[/url\]#i'
   );

   $format_replace=array(
      '<a class="lforum" target="_blank" href="$1">$2</a>'
   );

   $str=preg_replace($format_search, $format_replace, $str);
   $str=nl2br($str);
   return $str;
}

now i want also this : when a user insert a normal text with a link, this must be trasformed too. i can't do this trought preg_replace function, because if i write a code as

$format_search
'#(www\..*?)#i'

$format_replace
'<a class="lforum" target="_blank" href="$1">$1</a>'

it will convert the link 2 time (in the [url] and when the link is without this tag).

so i think to this function :

    function checkLinks($string) {
    $arrelab="";
    $arr=split(' |\r\n', $string);
    for($i=0; $i<sizeof($arr); $i++) {
        echo $i." - ".$arr[$i]."<br/>";
        if ((strpos($arr[$i], 'www.')!==false) or (strpos($arr[$i], 'http://')!==false) or (strpos($arr[$i], 'ftp://')!==false)) {
            if (strpos($arr[$i], '[url=')===false) {
                $arr[$i]='<a class="lforum" target="_blank" href="'.$arr[$i].'">'.$arr[$i].'</a>';
            }
        }

        $arrelab=$arrelab." ".$arr[$i];
    }
    return $arrelab;
}

the problem is that i need a split as for the newline, as for the empty space. any help would be appreciated.

p.s. sorry for my bad english :)

cheers

Answer 1

Your problem can be identified by reading your title.. parsing in combination with regex

You can't 'parse' html or bb-code with a regular expression because they are not regular languages.

You should write (or find) a bb-code parser instead of using regular expressions.

Google's first result for a BB-code parser is NBBC: The New BBCode Parser. But I've never used it so I can't comment on the quality.

Answer 2

AUTHOR COMMENT

uhm, but for what i must do regex works. that's my whole function :

function forumBBCode($str){
   $format_search=array(
      '#\[b\](.*?)\[/b\]#is',
      '#\[i\](.*?)\[/i\]#is',
      '#\[u\](.*?)\[/u\]#is',
      '#\[s\](.*?)\[/s\]#is',
      '#\[quote=(.*?)\](.*?)\[/quote\]#is',       
      '#\[img\](.*?)\[/img\]#i',
      '#\[url=(.*?)\](.*?)\[/url\]#i',  

      '#(\:acc\:)#i',
      '#(\:bang\:)#i',
      '#(\:haha\:)#i',
      '#(\:nono\:)#i',
      '#(\:plause\:)#i',
      '#(\:rock\:)#i',
      '#(\:roto\:)#i',
      '#(\:sigh\:)#i',
      '#(\:\))#i',
      '#(\:\()#i',
      '#(\:uhm\:)#i',
      '#(\:yeah\:)#i',                                                                                        

      '#\[color=\#?([A-F0-9]{3}|[A-F0-9]{6})\](.*?)\[/color\]#is' // Font color ([color=#00F]text[/color])  
   );

   $format_replace=array(
      '<strong>$1</strong>',
      '<em>$1</em>',
      '<span style="text-decoration: underline;">$1</span>',
      '<span style="text-decoration: line-through;">$1</span>',
      '<blockquote class="quotearea"><i><a class="lblackbu" href="./index.php?status=userview&userv=$1">$1</a> wrote :</i><br />$2</blockquote>',
      '<a href="$1" target="_blank"><img width="200" height="200" src="$1" alt="" /></a>',
      '<a class="lforum" target="_blank" href="$1">$2</a>',

      '<img border="0" alt="" src="./img/smiles/acc.gif" />',
      '<img border="0" alt="" src="./img/smiles/bang.gif" />',
      '<img border="0" alt="" src="./img/smiles/haha.gif" />',
      '<img border="0" alt="" src="./img/smiles/nono.gif" />',
      '<img border="0" alt="" src="./img/smiles/plause.gif" />',
      '<img border="0" alt="" src="./img/smiles/rock.gif" />',
      '<img border="0" alt="" src="./img/smiles/roto.gif" />',
      '<img border="0" alt="" src="./img/smiles/sigh.gif" />',
      '<img border="0" alt="" src="./img/smiles/smile.gif" />',
      '<img border="0" alt="" src="./img/smiles/uff.gif" />',
      '<img border="0" alt="" src="./img/smiles/uhm.gif" />',
      '<img border="0" alt="" src="./img/smiles/yeah.gif" />',                

      '<span style="color: #$1;">$2</span>'
   );

   $str=preg_replace($format_search, $format_replace, $str);
   $str=nl2br($str);
   return $str;
}

it works, expect for this problem (and the recursive quote, that i'll try to solve after this problem)

Answer 3

The easiest option would be to parse the plain-text urls first and ensure they don't come immediately after an equals sign.

Update from Marios:

preg_replace('#(?<![>/"])(((http|https|ftp)://)?www[a-zA-Z0-9\-_\.]+)#im', '<a href="$1">$1</a>'

Answer 4

It's easy to workaround with a lookbehind assertion.

preg_replace('#(?<![>/"])((http://)?www.........)#im', '<a href="$1">$1</a>'

Thus the regex will skip any URL enclosed in " or > or preceeded by /
It's a workaround, not a solution.

PS: target="_blank" is user pestering. Cut it out.

Answer 5

There is an easier way to do this. I have created a walk through in the RedBonzai Developers blog. The link to it is here: http://www.redbonzai.com/blog/web-development/how-to-create-a-bb-codes-function-in-php/

Let me know if you have any questions.

RedBonzai