Why does preg_replace_callback never fire in this function?

Question

In the function below, the save_content function runs, but the doReplace does not (echo

"This is the doReplace" never shows. Any ideas why?

add_action('content_save_pre', 'save_content');

 function save_content($content){
  global $post;
  $mykeyword = rseo_getKeyword($post);
  $mykeyword = preg_quote($mykeyword, '/');
  $content = preg_replace_callback("/\b($mykeyword)\b/i","doReplace", $content);
 return $content;
 }

 function doReplace($matches)
 {
  echo "This is the doReplace";
  die;
  }

Answer 1

Your function needs to return the data, not echo it..

function doReplace($matches) {
    return "This is the doReplace";
}

Hope that helps..

Answer 2

Shouldn't the preg_quote() call be used in an array map call? If you're feeding it something like "foo|bar" it'll get escaped as "foo\|bar", which won't match anything... Better use something like this:

// uncomment in case you're returning a string:
// $kw = explode('|', $kw);
// create a new function if php 5.3 is not an option
$regex = array_map(function($in) {
  return preg_quote($in, '/');
}, $kw);
$regex = implode('|', $regex);