how can I ensure string is surrounded by script tag in php?

Question

I have these imaginary strings:

$txts=
  array('<script src="http://code.jquery.com/jquery-2.1.4.min.js"></script>',
        '<script>document.getElementById("demo").innerHTML = "Hello JavaScript!";</script>',
        'document.getElementById("demo").innerHTML = "Hello JavaScript!";');

Now I would like an elegant simple solution to check if the <script> and </script> tags are surrounding the string and if not, surround the string with those tags. So, $txts[0] and $txts[1] are valid but $txt[2] should be surrounded with <script> </script>

I have a couple of solutions in my head but none 'sits' right with me, they are over complex or not clean.

Can you come up with a proper solution?

Answer 1

Does it have to be a regex solution? Loops over the array and repairs it if necessary. Ensures that you have an array with open and closing tags in the end.

<?php
$txts=
  array('<script src="http://code.jquery.com/jquery-2.1.4.min.js"></script>',
        '<script>document.getElementById("demo").innerHTML = "Hello JavaScript!";</script>',
        'document.getElementById("demo").innerHTML = "Hello JavaScript!";');

$opentag = "<script";
$closingtag = "</script>";
for ($i=0;$i<count($txts);$i++) {
    if (strpos($txts[$i], $opentag) === false) $txts[$i] = $opentag.">".$txts[$i];
    if (substr($txts[$i], -(strlen($closingtag))) !== $closingtag) $txts[$i] .= $closingtag;
}
print_r($txts); // all entries have open and closing tags in the end
?>

Answer 2

Check each array element:

foreach($txts as $txt) {
        return is_int(strpos($txt, '<script')) && is_int(strpos($txt, '</script>')));
}

Or via a function:

function checkTags($beggining, $ending, $string)
{
     return is_int(strpos($string, $beggining)) && is_int(strpos($string, $ending)))
}

Calling function for each element

foreach($txts as $txt) {
   if(!checkTags('<script','</script>', $txt)) {
       //treat error case
   }
}

Note: is_int is used because the substring might be at possition 0 (the beginning as in your case) and evaluates as false .

Answer 3

/^<script[^<]*>/ makes sure the opening tag is complete

/<\\/script>$/ makes sure the closing tag is there

I would do it this way:

$txts = array(
    '<script src="http://code.jquery.com/jquery-2.1.4.min.js"></script>',
    '<script>document.getElementById("demo").innerHTML = "Hello JavaScript!";</script>',
    'document.getElementById("demo").innerHTML = "Hello JavaScript!";'
);

foreach ($txts as &$txt) {
    if (!preg_match('/^<script[^<]*>/', $txt)) {
        $txt = '<script>' . $txt;
    }

    if (!preg_match('/<\/script>$/', $txt)) {
        $txt = $txt . '</script>';
    }
}

var_dump($txts);

Output:

array(3) {
  [0]=>
  string(66) "<script src="http://code.jquery.com/jquery-2.1.4.min.js"></script>"
  [1]=>
  string(81) "<script>document.getElementById("demo").innerHTML = "Hello JavaScript!";</script>"
  [2]=>
  &string(81) "<script>document.getElementById("demo").innerHTML = "Hello JavaScript!";</script>"
}