I have the following regex expression which is to extract the source of any img tag in HTML.
/(<img).*(src\s*=\s*"([a-zA-Z0-9\.;:\/\?&=\-_|\r|\n]{1,})")/isxmU
However, it doesn't appear to be matching the following:
<IMG SRC='http://www.mysite.com/pix/lens/mtf/CAEF8512L.gif'>
How can I build it to match this as well?
You're only matching for double quotes. Try
/(<img).*(src\s*=\s*("|')([a-zA-Z0-9\.;:\/\?&=\-_|\r|\n]{1,})\3)/isxmU
Note that the first " has been replaced by ("|') and that the ending check is using the backreference to that group, \3.
Have you considered using an HTML parser to do this, instead?
You should really not use regex for that kind of things : HTML is quite not regular enough for regular expressions...
What if you have, for instance, one of those :
<img src="..." />
<img src='...' />
<img src="...">
<img src="..." alt="..." />
<img alt="..." src="..." />
<img alt="..." src="..." style="..." />
Instead, you should use an HTML parser, like, for instance, DOMDocument::loadHTML.
With that, once your HTML document is loaded as a DOMDocument, you can use Xpath queries, or go through the DOM, to extract the specific informations you need.
For instance, considering you have this portion of HTML in a variable :
$html = <<<HTML
<p>test</p>
<img src="http://www.example.com/image-1.png" />
plop glop
<img alt="booh" src="http://www.example.com/image-2.png" />
huhu ?
<img alt="booh again" src='http://www.example.com/image-3.jpg' />
HTML;
You could :
DOMDocumentgetElementsByTagName method to get all img tags src attribute of each one, with the getAttribute methodWhich means some code like this one :
$dom = new DOMDocument();
$dom->loadHTML($html);
$nodes = $dom->getElementsByTagName('img');
foreach ($nodes as $img) {
var_dump($img->getAttribute('src'));
}
And the ouput you get will look like this :
string 'http://www.example.com/image-1.png' (length=34)
string 'http://www.example.com/image-2.png' (length=34)
string 'http://www.example.com/image-3.jpg' (length=34)
Not really hard to write -- and it should work much better than regexes, when it comes to extracting data from an HTML document !
I ended up using http://simplehtmldom.sourceforge.net/. Was quick and easy.