PHP Regular Expression that returns array of matches (preg_match vs preg_match_all)

Question

I am trying to get an array of all the successful matches of my Regex and in this case an array of all the Data URIs so as to iterate through the array and convert each Data URI to a file.

<?php
$string = '<img src="data:image/png;base64,FAKEIMAGE0XXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 0" /><img src="data:image/png;base64,FAKEIMAGE1XXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 1" /><img src="data:image/png;base64,FAKEIMAGE2XXXXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 2" /><img src="data:image/png;base64,FAKEIMAGE3XXXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 3" />';
$pattern = '@src="([^"]+)"@';
echo preg_match($pattern, $string, $matches, PREG_OFFSET_CAPTURE);
var_dump($matches);

I would like a result like below:

 Array(4) { [0]=> string(60) "data:image/png;base64,FAKEIMAGE0XXXXXAKJDBFLASDGFSDGAFJLSD==" [1]=> string(60) "data:image/png;base64,FAKEIMAGE1XXXXXAKJDBFLASDGFSDGAFJLSD==" [2]=> string(62) "data:image/png;base64,FAKEIMAGE2XXXXXXXAKJDBFLASDGFSDGAFJLSD==" [3]=> string(61) "data:image/png;base64,FAKEIMAGE3XXXXXXAKJDBFLASDGFSDGAFJLSD==" }

You mean : http://php.net/manual/en/function.preg-match-all.php ? — Justinas, Mar 30 '18 at 11:39

The fourth bird · Answer 1 · 2018-03-30T11:46:46.730

You could use DOMDocument and find the images with getElementsByTagName instead of using regex to parse html:

$string = '<img src="data:image/png;base64,FAKEIMAGE0XXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 0" /><img src="data:image/png;base64,FAKEIMAGE1XXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 1" /><img src="data:image/png;base64,FAKEIMAGE2XXXXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 2" /><img src="data:image/png;base64,FAKEIMAGE3XXXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 3" />';
$dom = new DOMDocument();
$dom->loadHTML($string);
$srcs = [];
foreach ($dom->getElementsByTagName('img') as $img) {
    $srcs[] = $img->getAttribute("src");
}
var_dump($srcs);

Demo

Plus one for suggesting DOMDocument. I would also go this way instead of hassling with regex. — Gogol, Mar 30 '18 at 11:50

score 0 · Answer 2 · answered Mar 30 '18 at 11:59

Rewriting the code with the following code solves the issue of getting the array of results assigned to $matches :

$string = '<img src="data:image/png;base64,FAKEIMAGE0XXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 0" /><img src="data:image/png;base64,FAKEIMAGE1XXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 1" /><img src="data:image/png;base64,FAKEIMAGE2XXXXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 2" /><img src="data:image/png;base64,FAKEIMAGE3XXXXXXAKJDBFLASDGFSDGAFJLSD==" alt="Fake img 3" />';
$pattern = '@src="([^"]+)"@';
echo preg_match_all($pattern, $string, $matches, PREG_OFFSET_CAPTURE);
var_dump($matches[1]);

PHP Regular Expression that returns array of matches (preg_match vs preg_match_all)

2 Answers2