Small Problem with Char Validation

[Siberd]

I wanna write a quick php strong validation, to check a user entry is alphanumeric only.. i'm using ereg and i can't make it work.. everytime it just ignores what i've put. any ideas?
the code is:

if(ereg("[[:alnum:]]", $uname))
{
do stuff
}
else
{
tell em its not alphanumeric
}
cheers /Sib
programmer in the making
icq: 44167565
e-mail: siberdude@ntlworld.com

 

[Siberd]

Ok, the script now partially works, except if the user enters speechmarks, it allows them through, enaces in escape slashes ( \" ). ANyone have any ideas how to get around this?
cheers /Sib
programmer in the making
icq: 44167565
e-mail: siberdude@ntlworld.com

 

[Siberd]

also the charactors : send it funky.. it also seems as tho as long as it actually conatins a letter it can have all the funky charactors in it it wants. /Sib
programmer in the making
icq: 44167565
e-mail: siberdude@ntlworld.com

 

[KarveR]

This should work on the principle that if it aint alphanumeric only (with escape slashes removed) then it aint right.

if (!ereg("[a-zA-Z0-9]+", stripslashes($uname)))
{
tell em its not alphanumeric
}
else
{
do stuff
}
***************************************
Party on, dudes!

 

[Guest_imported]

nope.. that didn't do it, it stops the first char being the non-palhanumeric.. same as the other method.
I can't see what it shouldn't work.. got me baffeled.. maybe i'll just try and use some kind of CharAt() and for loop method to check each charactor...
Cheers
Siberd

 

[KarveR]

nope.. that didn't do it, it stops the first char being the non-palhanumeric..

So you want the first character to be non alpha numberic?
If non alphanumeric what character do you want it to be?
***************************************
Party on, dudes!

 

[AnakinPt]

try this:

if (!ereg("^[a-zA-Z0-9]+$",$login)){
// wrong login
}

this way checks for the alfanum in the begging and end of string.

in Reg Exp: ^ - means begging of string
$ - end of string. Anikin
Hugo Alexandre Dias
Web-Programmer
anikin_jedi@hotmail.com

 

[Siberd]

i need a user-definatable string (IE when signing up for a user account, creating a log in name) to be completley alpha numeric.. with no nasty chars in it anywhere. ie.. l337d0wd would be fine... but l33=d()wd would cause "Invalid username" to be reported back
the code i had "if(ereg("[[:alnum:]]", $uname))" would stop the first charactor being non-alpha numberic (IE it couldn't be @) but it didn't stop speach marks (&quot or colons ) and if the non-aplha numeric charactor was in the second slot of the string (IE p@) it would let it through
KarveR's code ( if (!ereg("[a-zA-Z0-9]+", stripslashes($uname))) ) also produced the same results. with the exception, it prevented the " and : problem (as " and : don't fall in a-z A-Z or 0-9)however it would only check the first charactor.
i think the only way i'm going to be able to do this succesfully would be with a for loop, and some javascript, which checks the string, sets the value of a hidden form element, and passes that to the php script, which i can then if-test to see it it's, true or false.
if anyone has any better ideas, please let me know.
Cheers.
/Sib
programmer in the making
icq: 44167565
e-mail: siberdude@ntlworld.com

 

[KarveR]

slight change .. the + indicates 1 or mor of any one character in the set.
* indicates any combination of any character in the set. (allegedly) Hopefully this will solve it for you.

if (!ereg("[a-zA-Z0-9]*", stripslashes($uname))) ***************************************
Party on, dudes!

 

[Siberd]

with a little messing around.. a change of function, and a bit of theft (thank your KarveR) i managed a workable statement, that does the job, beutifully.

if (preg_match("/^[a-zA-Z0-9]+$/", stripslashes($uname)))

i new perl would come in handy again one day
*sigh of relief*
Thanks for the help fellas.
Cheers. /Sib
programmer in the making
icq: 44167565
e-mail: siberdude@ntlworld.com

 

[KarveR]

Learning is a good thing, if it doesn't work you can't possibly break it anyway ***************************************
Party on, dudes!