Delete string between strings and replace with text plus counter

Question

I want to remove all base64 images from a string

<img src="data:image/png;base64,iVBORw0..="><img src="data:image/png;base64,iVBORw1..=">...

and replace them with image1, image2 and so on.

<img src=" image1"><img src=" image2">...

So I am deleting the base64 part of the string and replacing it with "image" followed by the occurrence counter but it's not working so I get image1 all the time.

What can I do? Thanks!!

This is my code so far:

    $replacement = "image";
    $stringResult= deleteBase64_andReplace("data:", "=", $replacement, $string);
    echo $stringResult;



function deleteBase64_andReplace($start, $end, $replacement, $string) {
    $count = 0;

    $pattern = '|' . preg_quote($start) . '(.*)' . preg_quote($end) . '|U'; 
 
    while (strpos($string, $start) !== false) { 
    return preg_replace($pattern, $replacement.++$count, $string); 

    }
    
}

Unrelated but `preg_quote` should have `|` as its second parameter. `preg_quote($start, '|')`, second parameter is the delimiter. — user3783243, May 16 '22 at 11:01

score 2 · Accepted Answer · answered May 16 '22 at 10:52

You need to replace the deleteBase64_andReplace function with

function deleteBase64_andReplace($start, $end, $replacement, $string) {
    $count = 0;
    $pattern = '|' . preg_quote($start, '|') . '(.*?)' . preg_quote($end, '|') . '|s'; 
    while (strpos($string, $start) !== false) { 
        return preg_replace_callback($pattern, function($m) use ($replacement, &$count) {
            return $replacement . ++$count;}, $string); 
    }
}

See the PHP demo. Output is <img src="image1"><img src="image2">.

Notes:

preg_replace is replaced with preg_replace_callback to be able to make changes to $count when replacing the subsequent matches
preg_quote($start, '|') . '(.*?)' . preg_quote($end, '|') now escapes the regex delimiter char, you chose | and it needs to be escaped, too
I suggest omitting U flag and replace .* with .*? to make the regex more transparent

thanks a million, @Wiktor Stribiżew!! preg_replace_callback worked like a charm! — , May 16 '22 at 10:56

Delete string between strings and replace with text plus counter

1 Answers1