Trying to figure out how to limit variable size to limit user input

[dave247]

Unless buffer overflows or breaking out of code to perform a new command are problems that have been solved....

 

I am trying to figure out the proper PHP method for setting a boundary on a variable within a script. I have this variable $name which is fed a value from $_POST['name'] from a form field. Now this form field is limited in the HTML to accept only 20 characters, but someone could easily edit the form or outgoing post data. So I want to know how to limit the variable size in the script. In other languages it could be something like this: var name(20). So how do I do that in PHP?

[digibucc]

substr

 

http://php.net/manual/en/function.substr.php

 

something like:

 

<?php
$name = substr($_POST['name'], 0, 20);
?>

[Pikachu2000]

If validating the input, rejecting it, and redisplaying the form to the user with an error message is what you're ultimately after, strlen would be appropriate.

if( strlen($variable) > 20 ) {
     // oh, nooooooeessss! Too long!
}