php上的htmlentities <code></code> 只要！

Question

I want to run htmlentities() only on the contents within <code> things to strip </code>

I Wrote a function that takes a string and finds the content in between <code> </code>

function parse_code($string) {

  // test the string and find contents with <code></code> preg_match('@<code>(.*?)</code>@s', $string, $matches); // return the match if it succeeded if($matches) { return $matches[1]; }else { return false; } } 

However I need some help with a function that will will actually run htmlentities(); on the contents within <code> </code> and then implode() it all back together. For example lets say we have the string below.

<div class="myclass" rel="stuff"> things in here </div>
<code> only run htmlentites() here so strip out things like < > " ' & </code>
<div> things in here </div>

Once again, The function would need to keep all contents of the string the same but only modify and run htmlentities() on the contents of <code> </code>

Answer 1

You can simplify this with using a custom callback function:

$html = preg_replace_callback(
     "@  (?<= <code>)  .*?  (?= </code>)  @six",
     "htmlentities_cb", $html
);

function htmlentities_cb($matches) {
    return htmlentities($matches[0], ENT_QUOTES, "UTF-8");
}

The syntax for matching the enclosing code tags is called lookbehind and lookahead assertion . It simplifies the callback and avoids implode() later, because the assertion matches itself do not become part of $matches[0]. While @six is for case-insensitve tag matches and allows whitespace in the regex to make it more readable.