preg_replace with urlencode

Question

I am trying to create hashtag links with preg_replace and I encounter issues when a "" in the hashtag is present. I am not really good at patterns so any help would be appreciated:

My pattern:

$hashtags_url = '/(\#)([x00-\xFF]+[a-zA-Z0-9x00-\xFF_\w]+)/';

$body = preg_replace($hashtags_url, '<a href="'.$hashtag_path.'$2" title="#$2">#$2</a>', $body);

This works perfect to a normal hashtag but the issue is when i try to urlencode the $2 parameter.

I tried

$hashtags_url = '/(\#)([x00-\xFF]+[a-zA-Z0-9x00-\xFF_\w]+[x00-\xFF]+[a-zA-Z0-9x00-\xFF_\w])/';

and

   $body = preg_replace_callback(
$hashtags_url,
function($matches) {
    return "<a href=\"$hashtag_path/hashtag/".urlencode($matches[2])."\">#".
           $matches[2]."</a>";
},
$body);

and it goes well but now the single-worded hashtags are omitted.

Answer 1

You can use the following simplified regex, with $matches[1] to access the hashtag name in the anonymous function used as the replacement argument:

/#(\S+)/

Make sure you pass all necessary variables using use keyword to the callback function (see use ($hashtag_path)).

See the PHP demo:

$body = "Text text #hashtag text text #hast/tag";
$hashtag_path = '/path/to';
$hashtags_url = '/#(\S+)/';
$body = preg_replace_callback(
$hashtags_url, function($matches) use ($hashtag_path) {
    return "<a href=\"$hashtag_path/hashtag/".urlencode($matches[1])."\">".$matches[0]."</a>";
},
$body);
echo $body;

Output:

Text text <a href="/path/to/hashtag/hashtag">#hashtag</a> text text <a href="/path/to/hashtag/hast%2Ftag">#hast/tag</a>