preg_match to match src=, background= and url(..)

Question

I would like to find a regular expression that could find (in given HTML) the following images:

• Those captured in: src=""
• Those captured in: src=''
• Those captured in: background=""
• Those captured in: background=''
• Those captured in: url("")
• Those captured in: url('')
• Those captured in: url()

So far i came up with:

preg_match_all("/src=((\"|'|)?(.*\.(png|gif|jpg))(\"|'|))/Ui", $strHTML, $arrMatches);

preg_match_all("/background=((\"|'|)?(.*\.(png|gif|jpg))(\"|'|))/Ui", $strHTML, $arrMatches);

preg_match_all("/url\((\"|'|)?((.*\.(png|gif|jpg))(\"|'|))\)/Ui", $strHTML, $arrMatches);

But those are incomplete in that they don't include the prefix (src/background/url). Also, security wise I think they can be improved further, to prevent somebody from entering src="http://somesite.com/someurl.exe?ext=jpg"

Any help in the right direction is appreciated.

edit:

I think i got it, although the code can surely be improved, possibly even combined and/or optimized :)

/* match CSS url() links */

preg_match_all("/(url\((\"|'|)(.*\.(png|gif|jpg|jpeg))(\"|'|)\))/Ui", $strHTML, $arrMatches);

Array
(
    [0] => Array
        (
            [0] => url('test1.gif')
            [1] => url(test2.gif)
            [2] => url("test3.gif")
        )

    [1] => Array
        (
            [0] => url('test1.gif')
            [1] => url(test2.gif)
            [2] => url("test3.gif")
        )

    [2] => Array
        (
            [0] => '
            [1] => 
            [2] => "
        )

    [3] => Array
        (
            [0] => test1.gif
            [1] => test2.gif
            [2] => test3.gif
        )

    [4] => Array
        (
            [0] => gif
            [1] => gif
            [2] => gif
        )

    [5] => Array
        (
            [0] => '
            [1] => 
            [2] => "
        )

)

/* match img links */
preg_match_all("/(src=(\"\'??)(.*\.(png|gif|jpg|jpeg))(\"\'??))/Ui", $strHTML, $arrMatches);

/* match background links */
preg_match_all("/(background=(\"\'??)(.*\.(png|gif|jpg|jpeg))(\"\'??))/Ui", $strHTML, $arrMatches);

Answer 1

If you're sure about those attribute names (src,url and background)...

$arr = array(
    'url("http://somesite.com/someurl.exe?src=jpg")',
    'url(http://somesite.com/someurl.exe?src=jpg)',
    'src="http://somesite.com/someurl.exe?src=jpg"',
    'src="http://somesite.com/someurl.exe?ext=jpg"',
    'background="http://somesite.com/someurl.exe?src=jpg"'
);
foreach ($arr as $str) {
    preg_match_all('/(?<=src=|background=|url\()(\'|")?(?<image>.*?)(?=\1|\))/i',$str,$matches);
    echo $str;
    foreach($matches['image'] as $img) {
        echo "\nimage: <b>$img</b>\n";
    }
    echo "\n";
}