preg_match - windows filenames

[Chuck Anderson]

I am trying to work out the preg_match command to check windows
filenames for illegal characters and I can not seem to get it right.
The disallowed characters are \/:*?"<>|

I can not figure out the correct syntax.

Here's my best guess (which does not work). I'm using % to delimit the
characters and I've added backslashes to escape most of the characters
because they are also pattern modifiers.

$matches = preg_match("%\\/:\*\?\"<>\|%", $filename);
if ($matches > 0)
echo "illegal filename - $filename";

The above does not match the colon if I submit abc: as the filename.

Any help would be much appreciated (and maybe then I can figure out how
this works).

--
*************** **************
Chuck Anderson • Boulder, CO

http://www.CycleTourist.com

Integrity is obvious.
The lack of it is common.
*************** **************

[John Dunlop]

Re: preg_match - windows filenames

Chuck Anderson wrote:
[color=blue]
> The disallowed characters are \/:*?"<>|[/color]

[...]
[color=blue]
> %\\/:\*\?\"<>\|%[/color]

Set them in a character class, otherwise the pattern will
match only if *all* those characters occur _in the order you
specified_. Alternatives is another way, but less efficient.

%[\\\/:*?"<>|]%

(Note the three backslashes instead of two. The backslash
must be escaped twice - once because it's in a string and
again for the regex engine. The other characters don't need
escaping, except " if you double quote your string.)

--
Jock

[Chuck Anderson]

Re: preg_match - windows filenames

John Dunlop wrote:
[color=blue]
>Chuck Anderson wrote:
>
>
>[color=green]
>>The disallowed characters are \/:*?"<>|
>>
>>[/color]
>
>[...]
>
>
>[color=green]
>>%\\/:\*\?\"<>\|%
>>
>>[/color]
>
>Set them in a character class, otherwise the pattern will
>match only if *all* those characters occur _in the order you
>specified_. Alternatives is another way, but less efficient.
>
> %[\\\/:*?"<>|]%
>
>(Note the three backslashes instead of two. The backslash
>must be escaped twice - once because it's in a string and
>again for the regex engine. The other characters don't need
>escaping, except " if you double quote your string.)
>
>
>[/color]
Thank you, thank you. I hesitated asking because it seemed like I was
looking for a "free handout."
This clarifies things, though, and now I know more about regular
expressions.

--
*************** **************
Chuck Anderson • Boulder, CO

http://www.CycleTourist.com

Integrity is obvious.
The lack of it is common.
*************** **************

[Alvaro G Vicario]

Re: preg_match - windows filenames

*** Chuck Anderson wrote/escribió (Tue, 02 Aug 2005 12:43:27 -0600):[color=blue]
> I am trying to work out the preg_match command to check windows
> filenames for illegal characters and I can not seem to get it right.
> The disallowed characters are \/:*?"<>|
>
> I can not figure out the correct syntax.[/color]

Hope this helps (not tested):

$forbidden=preg _quote('\/:*?"<>', '/');
preg_match('/[' . $forbidden . ']/', $filename);


--
-- Álvaro G. Vicario - Burgos, Spain
-- http://bits.demogracia.com - Mi sitio sobre programación web
-- Don't e-mail me your questions, post them to the group
--