Test if string could be boolean PHP

Question

I\'m getting a string from a $_GET and I want to test if it could be a boolean, before I use it for a part of a mysql query. Is there a better way of doing it than:

Answer 1

For what it's worth, if you really wanted to accept "yes" or "no" as valid input from the user, then I'd do something like this:

function toBoolean($string){
    $string = strtolower($string);
    if ($string == "true" || $string == "1"|| $string == "yes" )
        return true;
    elseif ($string == "false" || $string == "0" || $string == "no")
        return false;
    else
        throw new Exception("You did not submit a valid value, you naughty boy");
}

try {
    $query = "SELECT * FROM my_table WHERE male=" . (toBoolean($_GET['male']) ? "1" : "0" );
    $result = mysql_query($query) or die(mysql_error());
} catch (Exception $e) {
    // handle bad user input here
}

Answer 2

You can use is_bool to test your string:

if(is_bool($val)){
  // is boolean
}else{
  // not a boolean
}