regex & Special Characters

[christopherkowalski]

I needed a quick means of limiting characters in user-provided form data throughout my application, so I came up with the following regex script which can be modified on a per-field basis for whatever characters I want a given field to support. As a point of reference I wanted to start by coming up with a default, or a means of allowing standard characters that might appear in an English string, but I'm having a little problem. Here is what I came up with:

<CFIF refind("[^A-Za-z0-9!\@\##\$%\&\*-_\+:',\?\./]", form.variable_name, 1) GT 0>

...code to execute here...

</CFIF>

This regex script essentially allows for letters, numbers, and: ! @ # $ % & * - _ + : ' ? . /

In testing this, I tried entering various special characters, and in all cases I tested the regex script caught anything not in my list.

That is, until I used the "^" symbol. That flew right through. Then I discovered "[" and "]" did too. If these were, who knows what else would?

So that brings me here. I am not a fan of writing regex scripts, do it so infrequently, and thus are not very savvy at it.

Am I doing something wrong? Is there a better way to do this perhaps?

[TiGGi]

Try using FindOneOf.

[Adam Cameron.]

This threw me for a bit.

You're not escaping your -, so the regex engine is treating "*-_" as a range.  So everything from ASCII 42 to ASCII 95 - which includes those special characters mention - will match.

--

Adam

[insuractive]

I recommend checking out the software package The RegEx Coach (http://weitz.de/regex-coach/).  It provides a simple, great interface for writing and testing regular expression patterns.  Using something like that should allow you to see visually that your problem is.