[SOLVED] Figuring out secure form input

[siwelis]

I'm trying to figure out how to do this while hoping it's the right way to do it;

 

The part that determines if user inputs "ANY IRREGULAR CHARACTERS OR CODE" (sql/php) what I don't know how to do.

 

$inputerrors = "You've had some inputting problems, dude."
if($_POST['article_title'] HAS ANY IRREGULAR CHARACTERS OR CODE)
//then return;
$inputerrors .= "It seems as though you're trying to pass code into our servers. Your IP address is $gosun and your ISP is $goto. A likely photo and address of you may be $crossreferenced. If this happens more than 3 times, you will be banned and $goto will be informed of any malicious conduct. If you would just like to hack please go to my hacking server and have some educational malicious fun there.";
echo $inputerrors;
exit();

 

Thank you for all of your help. I try to answer questions on here if I can so I can give back too... And once I'm making money from my site of course, I will still be coming here for help most likely and definitely donating to show my appreciation. Thank you! Any suggestions?

[warewolfe]

What characters to you want to permit? Only Alphanumerics? Or some others like hyphen and single quotes?

 

[siwelis]

I want to accept anything that can't be executed as code... If that's too general then alphanumerics would do.

 

Thank you for your response!

[warewolfe]

function checkInput($string)
{
  return preg_match('/^[a-z0-9\s]*$/i', $string);
}

This will accept letters, number and spaces. If you want full stops and other punctuation just escape the character and add within the square brackets. eg [a-z09\s\.] will let people add a full stop at the end of a sentence.

[warewolfe]

also it may be a good idea to put to following in as well

$input =  htmlentities($_POST['article_title'],ENT_QUOTES,UTF-;
if(checkInput($input))
{
   echo"accepted<br />";
}
else
{
  echo"rejected<br />";
}

 

[siwelis]

Thank you. You have led me in the right direction!

[siwelis]

function checkInput($string)
{
  return preg_match('/^[a-z0-9\s]*$/i', $string);
}

This will accept letters, number and spaces. If you want full stops and other punctuation just escape the character and add within the square brackets. eg [a-z09\s\.] will let people add a full stop at the end of a sentence.

 

I'm actually still trying to figure out where to use this code...