title: change php output buffer before flush
body: <p>Is there anyway to change output buffer before flush it?
  I tried this function ob_set_contents but it seems there is no such a function,
  I have the following in my header.php file:</p>
  
  <pre><code>ob_start(null,0,PHP_OUTPUT_HANDLER_CLEANABLE);
  </code></pre>
  
  <p>I need to do such a following in end of my footer.php file:</p>
  
  <pre><code>$output = ob_get_contents();
  $output=str_ireplace("&lt;-BlogXmlLink-&gt;","/en/rss.xml",$output);
  ob_set_contents($output);
  ob_end_flush();
  </code></pre>