Archives for February 2011

February 28, 2011

Replace eregi with preg_match

A couple of weeks ago, I wrote a small PHP code to validate if the url being passed is in fact valid. I used a regular expression and PHP’s eregi function to find a pattern match. Looking back, the problem is, the eregi function is deprecated in PHP 5.3.0.

For compatibility going forward, we need to replace eregi with the preg_match function which is better suited for regular expression matches. We will use the same example as last time. As you recall, the function was:

Code With eregi

$urlregex = "^(http|https|ftp)\://([a-zA-Z0-9\.\-]+(\:[a-zA-Z0-9\.&%\$\-]+)*@)*((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])|localhost|([a-zA-Z0-9\-]+\.)*[a-zA-Z0-9\-]+\.(com|edu|gov|int|mil|net|org|biz|arpa|info|name|pro|aero|coop|museum|[a-zA-Z]{2}))(\:[0-9]+)*(/($|[a-zA-Z0-9\.\,\?\'\\\+&%\$#\=~_\-]+))*$";
 
if (eregi($urlregex, $_POST['url'])) {
//  url is valid. shorten long url
} else {
// reject. url is invalid
}

Code with preg_match

$urlregex = "^(http|https|ftp)\://([a-zA-Z0-9\.\-]+(\:[a-zA-Z0-9\.&%\$\-]+)*@)*((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])|localhost|([a-zA-Z0-9\-]+\.)*[a-zA-Z0-9\-]+\.(com|edu|gov|int|mil|net|org|biz|arpa|info|name|pro|aero|coop|museum|[a-zA-Z]{2}))(\:[0-9]+)*(/($|[a-zA-Z0-9\.\,\?\'\\\+&%\$#\=~_\-]+))*$";
 
if(!preg_match($urlregex, $_POST['url']))
// reject. url is invalid //
} else {
url is valid. shorten long url
}

Here, we’ve sucessfully replaced the eregi function with preg_match.

February 28, 2011

Form Validation Callbacks Within CodeIgniter

There are many ways to add form validation within CodeIgniter. One way is by extending the form validation library with your own. Another way is by using callbacks. CodeIgniter support callbacks to form validation. I would like to show how callbacks can be added to the existing form validation set of rules.

Validation Rules

Here’s a typical form validation rule where the ‘url’ field is required.

$this->form_validation->set_rules(‘url’, ‘URL’,'required’ );

Validation Rules with Callbacks

This is how you add callbacks. Notice the ‘callback’ prefix.

$this->form_validation->set_rules(‘username’, ‘Username’, ‘callback_url_check’);

The Callback Function

The callback function. The ‘callback’ prefix is omitted.

function url_check() { 
  $regex = “your reg ex code here”;
  if(!preg_match($regex, $str)) {
    $this->form_validation->
    set_message(‘valid_url’, ‘Please enter a valid URL.’);   return FALSE;
  } else {
    return TRUE;
  }
}

In the example above, you will need to supply your own regular expression to perform a url match. This is how you implement the callback function. It’s ideal for adding quick functions without extending the current CodeIgniter library.