替换长字符串中文件名中每个句点的出现次数

Question

$text = 'This is a long text containing different image paths like <img src="/site/assets/files/5136/image1.jpg" width="750" />. The text may contain more than one image, here's another one: <img src="/site/assets/files/5136/image1.1.jpg" width="750" />';

Please consider the example text above. I'm looking for a good way to replace period characters in filenames inside a string, that may contain multiple filenames. 'image1.1.jpg' should become 'image1_1.jpg', so the period should be replaced by an underscore. Only period characters that belong to a filename should be replaced. The filename always looks like this:

/site/assets/files/5136/image1.1.jpg

/site/assets/files/425/image1.jpg

/site/assets/files/6524/image2.x.png

The bold parts are variable, the rest of the path is always the same. A filename may or may not contain a period. The extension is .jpg or .png and I only want to target images.

I would like to use PHP to do this.

Answer 1

Untested:

$new_text = preg_replace_callback('/(\/site\/assets\/files\/[^\/]+\/)([^\/]+)(\.[a-z0-9]+)/i', function ($matches) {
    return $matches[1] . str_replace('.', '_', $matches[2]) . $matches[3];
}, $text);

The regex matches all paths beginning with /site/assets/files followed by one more path segment plus a filename ending with an extension separated by a single dot (like .jpg, but not .tar.gz). The match has three groups: the folder path ($matches[1]), the filename ($matches[2]) and the extension ($matches[3]). str_replace is used to replace all dots (.) in $matches[2] with underscores (_).