how to write a pcre pattern to match specific tag

Question

I have a question related to pcre with php.

I have to write a little parser for a specific file and I don't know regex very well so I need some help.

This is input...

    blah blah [{img:xyzname}] one more blah blah[{root}]
and [{php:<?php ...echo 'phpcode';......?>}]

...so I have to replace these values with my ones, so here is what I did...

 $alt=preg_replace_callback('|\[{(.*[^}\]])}\]|iU',
                                        function ($match){
                                            $m=explode(':',$match[1]);


                                                switch($m[0]){

                                                    case 'img':
                                                            return $m[1]
                                                    break;
                                                    case 'php':
                                                            // i want that php code here in $m[1] but i am getting nothing
                                                    break;
                                                    default:
                                                            return 'UNDEFINED';
                                                    break;
                                                }
                                            }
                                        },$this->content);
            $this->content=$alt;

I tried many times with many patters and many tests, but I noticed that I was getting null or nothing, only when my [{php:<?php .....?>}] contains <? and only when I put < ?.

Answer 1

preg_match_all('/\[{(\w+):((?:(?!}]).)*)}]/', $this->content, $matches);
print(htmlspecialchars(var_export($matches, true)));

If you're trying this in a browser remember that < and > get treated as tags unless you replace them with &lt; and &gt;. That's why I used htmlspecialchars(). Using your input I get this:

array (
  0 => 
  array (
    0 => '[{img:xyzname}]',
    1 => '[{php:<?php ...echo \'phpcode\';......?>}]',
  ),
  1 => 
  array (
    0 => 'img',
    1 => 'php',
  ),
  2 => 
  array (
    0 => 'xyzname',
    1 => '<?php ...echo \'phpcode\';......?>',
  ),
)