Tag manipulation using DOMDocument

Question

On our main symfony2 application at work I have had to manipulate some outputted grid fields by wrapping them in a hyperlink tag. This happens in quite a few different controllers, so I made a method to do this to prevent code repetition.

I decided to do this using DOMDocument and construct the new hyperlink with that.

public function linkWrap($string, $route, array $route_params = [], $prefilter = null)
  {
    if(strlen($string) > 0)
    {
      $dom = new \DOMDocument();
      $new_hyper = $dom->createElement('a');
      $new_hyper->setAttribute('href', $this->generateUrl($route, $route_params).(isset($prefilter) ? '?'.htmlspecialchars($prefilter) : ''));
      $new_hyper->nodeValue = $string;

      return $dom->saveHTML($new_hyper);
    }

    return $string;
  }

The method takes a number of options the last of which is used only to append a prefilter query string for use with APYGridBundle.

My question is, does this cause a significantly larger overhead than just constructing the link in a more 'conventional' way?

As follows:

$link = "<a href=" . $this->generateUrl('a_route', array('id' => 23)) . '?'.$prefilter">some text</a>";

In addition, any tips on how any of could be improved would be appreciated.

Answer 1

Creating links using DOMDocument makes no sense to me.

I have created a simple benchmark for both methods.

Simple string concatenation is around 7 times faster on my computer:

Method Name          Iterations    Average Time      Ops/second
------------------  ------------  --------------    -------------
simpleLink        : [10,000    ] [0.0000013786793] [725,331.85764]
linkUseDomDocument: [10,000    ] [0.0000098103762] [101,932.89054]

You could reuse objects in (for example) static variables like this:

public function linkWrap2($string, $route, array $route_params = [], $prefilter = null)
{
    static $dom = null, $new_hyper = null;

    if(strlen($string) > 0)
    {
        if ($dom === null) {
            $dom = new \DOMDocument();
            $new_hyper = $dom->createElement('a');
        }

        $new_hyper->setAttribute('href', $this->generateUrl($route, $route_params).(isset($prefilter) ? '?'.htmlspecialchars($prefilter) : ''));
        $new_hyper->nodeValue = $string;

        return $dom->saveHTML($new_hyper);
    }

    return $string;
}

but it's only 30% faster.

My observations

Don't use htmlspecialchars in setAttribute value, because it will be encoded twice:

$new_hyper->setAttribute('href', $this->generateUrl($route, $route_params).(isset($prefilter) ? '?'.($prefilter) : ''));

However, you must use htmlspecialchars in simple concatenated strings:

$link = "<a href=" . $this->generateUrl('a_route', array('id' => 23)) . '?'.htmlspecialchars($prefilter).'">some text</a>';

Try to avoid custom query strings after a generated route URL. Instead of place value of $prefilter after the URL, you could place additional route params:

$this->generateUrl($route, array_merge($route_params, [ 'prefilter' => $prefilter ]));