如何从源文件中提取HTML元素

Question

I need to replace a HTML section identified by a tag id in a source code, which is combination of HTML and PHP using PHP. In case it's pure HTML, DOM parser could be used; in case there is no DIV in DIV, I can imagine how to use preg_match. This is what I am trying to do - I have a code (loaded into a string) like:

<div>
  <img >
</div>

<? include(); ?>

<div id="mydiv">
   <div>
      <div>
        <img >
      </div>
   </div>
</div>

and my task is to replace content of "mydiv" DIV with a new one e.g.

<div id="newdiv>
  some text
</div>

so the string will look like this after the change:

<div>
  <img >
</div>

<? include(); ?>

<div id="mydiv">
  <div id="newdiv>
    some text
  </div>
</div>

I have already tried:

1) parsing the code using DOMdocument's loadHTML => it produces a lot of errors in case PHP code is included.

2) I played around a bit with regexes like preg_match_all('/<div id="myid"([^<]*)<\/div>/', $src, $matches), which fails in case more child divs are included.

The best approach I have found so far is:

1) find id="mydiv" string

2) search for '<' and '>' chars and count them like '<'=1 and '>'=-1 (not exactly, but it gives the idea)

3) once I get sum == 0 I should be on position of the closing tag, so I know, which portion string I should exchange

This is quite "heavy" solution, which can stop working in some cases, where the code is different (e.g. onpage PHP code contains the chars as well instead of just simple "include"). So I am looking so some better solution.

Answer 1

You could try something like this:

$file = 'filename.php';
$content = file_get_contents($file);
$array_one = explode( '<div id="mydiv">' , $content );
$my_div_content = explode("</div>" , $array_one[1] )[0];

Or use preg_match like you said:

preg_match('/<div id="mydiv"(.*?)<\/div>/s', $content, $matches)