Simple random text generator in PHP
Posted by Marijn Rongen on December 8, 2009 in Webdesign tips
Lately I have encountered the need for random text generators in several of my clients' projects. Applications vary from anti-spambot security codes to automatic password generating. To retain a flexible solution applicable in all those circumstances and more I have created a simple function in PHP.
The function can be called with 2 arguments, the first controlling the lenght of the output string and the second sets the allowed characters. Both of these are optional, if you call the function without arguments a six character long alphanumeric string will be generated.
function generatePassword($length = 6,
$chars = '0123456789abcdefghijkmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
{
$password = '';
$char_length = strlen($chars);
srand((double)microtime()*1000000);
for ($i = 0; $i < $length; $i++)
{
$num = rand() % $char_length;
$password .= $chars[$num];
}
return $password;
}
The following line can be omitted when using PHP 4.2 or higher:
srand((double)microtime()*1000000);
The seeding of the random number generator happens automatically in later versions.
Below are some examples to demonstrate what this function can do for you.
generatePassword(); // May return: 9inhpS
generatePassword(8, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'); // May return: UYHCCZBD
generatePassword(4, '0123456789'); // May return: 2561
If you found this helpful or have any improvements I would love to hear it!
