PHP regular expression skip element

Question

I have written regular expression which converts text links into clickable link. The code works fine however when an HTML tag is passed it mess the code

Here is my code

$text = preg_replace('#(?<![">])((http|ftp)s?://[^<>\s]+)#i', '<a href="\\0">\\0</a>', $text );

It is suppose to skip following element

<a href="http://www.yahoo.com">Yahoo</a>

but it does not.. what am I doing wrong?

Thanks

it converts url like yahoo.com to <a href="yahoo.com">http://yahoo.com</a> What I am trying to do is to skip the <a href tags — Maximus
– Maximus, Commented Aug 16, 2010 at 18:05
Use the PHP DOM functions to only apply the regex to text nodes that are not within A tags. — Peter Boughton
– Peter Boughton, Commented Aug 16, 2010 at 18:08

Artefacto · Accepted Answer · 2010-08-16 18:06:13Z

1

It does skip it. " is before the URL, so the negative look behind makes it not match.

Anyway, to do this reliably, you should be using a HTML parser. You could transform only text nodes not worrying about existing HTML elements.

answered Aug 16, 2010 at 18:06

Artefacto

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rubber boots · Accepted Answer · 2010-08-16 18:16:23Z

0

After checking your code with two inputs:

$text1 = '<a href="http://www.yahoo.com">Yahoo</a>';
$text2 = 'text text http://www.yahoo.com text';

$reg = '{
         (?<![">])
         (
           (?:http|ftp)s? : // [^<>\s]+
         )
        }ix';

echo  preg_replace($reg, '<A HREF="\1">\1</A>', $text1 ) . "\n";
echo  preg_replace($reg, '<A HREF="\1">\1</A>', $text2 ) . "\n";

and reading the corresponding outputs:

=> #1 not touched  <a href="http://www.yahoo.com">Yahoo</a>
=> #2 modified     text text <A HREF="http://www.yahoo.com">http://www.yahoo.com</A> text

I'd ask you what you think what should be different?

Regards

rbo

answered Aug 16, 2010 at 18:16

rubber boots

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2 Comments

Maximus Over a year ago

#1 should output like <a href=" <a href="yahoo.com/"">http://www.yahoo.com/"</…>

Maximus Over a year ago

There was space after <a href="<SPACE> so the rule was ignoring it. I added \s and its working now

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