PHP Function To Convert Html Entities Back To Ascii

Last modified: 
Sunday, March 29th, 2015

This is a function to convert select HTML entities back to ASCII characters in PHP. Its initial purpose was undo the ENT_QUOTE setting in the Drupal 7 $head_title.

* Convert speficic HTML entities back to ASCII chars
* Consider the context and potential ramifications of converting any given HTML 
* entity back to ASCII, as this may introduce vulnerabilities. 
* @param $str 
*   The string to be manipulated.
* @param $more = FALSE
*   By default only ' and  " are converted. Set to TRUE to convert an
*   extended set of HTML entities. 
function htmlEntitytoAscii($str=NULL, $more=FALSE) {
  $search = array(''', '"');
  $replace = array("'", '"');
  $str = str_replace($search, $replace, $str);
  if ($more) {
    // You can add whatever you want here. str_replace iterates through the 
    // two arrays such that $replace[0] will replace all instances of 
    // $search[0] and so on.  
    $search = array('&');
    $replace = array('&');
    $str = str_replace($search, $replace, $str);
  return $str;

///// EXAMPLE USAGE /////

print 'View page source to see character transformations.';
print "
\n"; $string = '\' & "'; print 'Original: ' . $string; print "
\n"; $string = htmlspecialchars($string, ENT_QUOTES); print 'Converted to HTML entities: ' . $string; print "
\n"; print 'Back to ASCII: ' . htmlEntitytoAscii($string); print "
\n"; print 'Back to ASCII with $more=TRUE: ' . htmlEntitytoAscii($string, TRUE); print "

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