How to strip tags in PHP using regex?

Question

$string = 'text <span style="color:#f09;">text</span>
<span class="data" data-url="http://www.google.com"&gt;google.com&lt;/span&gt;
text <span class="data" data-url="http://www.yahoo.com"&gt;yahoo.com&lt;/span&gt; text.';

What I want to do is get the data-url from all spans with the class data. So, it should output:

$string = 'text <span style="color:#f09;">text</span>
http://www.google.com text http://www.yahoo.com text.';

And then I want to remove all the remaining html tags.

$string = strip_tags($string);

Output:

$string = 'text text http://www.google.com text http://www.yahoo.com text.';

Can someone please tell me how this can be done?

Answer 1

Try to use SimpleXML and foreach by the elements - then check if class attribute is valid and grab the data-url's

Answer 2

preg_match_all("/data/" data-url=/"([^']*)/i", $string , $urls);

You can fetch all URls a=by this way.

And you can also use simplexml as hsz mentioned

Answer 3

If your string contains more than just the HTML snippet you show, you should use DOM with this XPath

//span/@data-url

Example:

$dom = new DOMDocument;
$dom->loadHTML($string);
$xp = new DOMXPath($dom);
foreach( $xp->query('//span/@data-url') as $node ) {
    echo $node->nodeValue, PHP_EOL;
}

The above would output

http://www.google.com
http://www.yahoo.com

When you already have the HTML loaded, you can also do

echo $dom->documentElement->textContent;

which returns the same result as strip_tags($string) in this case:

text text
google.com
text yahoo.com text.

Answer 4

The short answer is: don't. There's a lovely rant somewhere around SO explaining why parsing html with regexes is a bad idea. Essentially it boils down to 'html is not a regular language so regular expressions are not adequate to parse it'. What you need is something DOM aware.

As @hsz said, SimpleXML is a good option if you know that your html validates as XML. Better might be DOMDocument::loadHTML which doesn't require well-formed html. Once your html is in a DOMDocument object then you can extract what you will very easily. Check out the docs here.