Way to stop all the ASCII Characters?

[crimsonmoon]

Is there a way to only allow number and letter in a field and not allow all those ASCII characters like ‡¤ñ etc etc


I don't like them for usernames as sometimes the browser doesn't read them and they make searching a pain!

[HuggieBear]

In Perl I'd use a regex to check that the field only contains Alpha-Numeric characters.  I'm sure php is capable of the same, but it may have a better function for it.

I'll look into this now.

Rich

[obsidian]

have you tried running a preg_match() on the user names?
[code]
<?php
if (!preg_match('|^[a-z0-9]+$|i', $_POST['username'])) {
  // contains invalid characters
  // only allows letters and numbers
}
?>
[/code]

[effigy]

Letters and numbers [i]are[/i] ASCII. Those are "extended ASCII" or "high ASCII."

[HuggieBear]

Obsidian,

You need to remove the additional 'http://' in the 'RegEx' link in your signature.  Just tried to get there  :)

Rich

[scottybwoy]

In Obsidians post what are the |^ and +$| characters for?  I understand the i is for case insensitive.

[HuggieBear]

The [color=red]|[/color] are the delimeters
the [color=red]^[/color] matches start of line
the [color=red]+[/color] matches one or more of the previous characters/classes (in this case classes)
the [color=red]$[/color] matches end of line

Rich

[HuggieBear]

A note that's very important when using regular expressions is the following quantifiers:

[color=red]*[/color] means 'Zero or more'
[color=red]?[/color] means 'Zero or one'
[color=red]+[/color] means 'One or more'

And the reason that Obsidian has added the [color=green]+[/color] at the end of the character class [color=green][a-z0-9][/color] is to indicate that there must be some data entered, had he have put the following:

|^[a-z0-9][b]*[/b]$|i

Note the * instead of +

Then an empty string would be considered as valid.

Rich

[obsidian]

[quote author=HuggieBear link=topic=105611.msg421957#msg421957 date=1156518884]
Obsidian,

You need to remove the additional 'http://' in the 'RegEx' link in your signature.  Just tried to get there  :)

Rich
[/quote]

thanks, rich... signature tends to get messed up on SMF for some reason.

[scottybwoy]

Cheers, so if I do :
[code]
<?php

$customer = preg_match('|^[a-z]+$i', $_POST['CUSTOMER']);
$customer = strtoupper($customer);
$cust = substr($customer, 0, 2);

?>
[/code]

I will get the first three letters entered in the string capitalised. Yeah?

[HuggieBear]

Correct, but you won't get the rest of the string, you realise that right?

Richard will yield RIC not RIChard.

Regards
Rich

[obsidian]

[quote author=scottybwoy link=topic=105611.msg421983#msg421983 date=1156522306]
Cheers, so if I do :
[code]
<?php

$customer = preg_match('|^[a-z]+$i', $_POST['CUSTOMER']);
$customer = strtoupper($customer);
$cust = substr($customer, 0, 2);

?>
[/code]

I will get the first three letters entered in the string capitalised. Yeah?
[/quote]

well, with that, you're not actually [b]doing[/b] anything with the preg_match(). also, you're missing your closing delimiter. you'll need to do something like this:
[code]
<?php
if (preg_match('|^[a-z]+$|i', $_POST['CUSTOMER']);
  // valid match
  $customer = strtoupper($_POST['CUSTOMER']);
  $cust = substr($customer, 0, 2);
}

?>
[/code]