php regex for min and max number length

if(strlen(trim($steamid)) != 0)
            {
                $regex = "/^STEAM_0:(0|1):[0-9]{1}[0-9]{0,8}$/";
                if(!ereg($regex, $ssteamid)){
                    echo "STEAM ID invalida";
                }
            }

My problem is that this isn't working as it should.

STEAM ID's have maximum of 18 characters and minimum of 17.

they always start with: STEAM_0:

Two true examples would be: ST开发者_C百科EAM_0:0:11111111 ; STEAM_0:1:1111111

And another thing is that after STEAM_0: always come an 0 or an 1 like demonstrated in the examples.

This:

$regex = "/^STEAM_0:(0|1):[0-9]{1}[0-9]{0,8}$/";

could be writter shorter as:

$regex = "/^STEAM_0:[01]:[0-9]{1,9}$/";

Since your ID is 17 or 18 chars long, adjust the regex to it:

$regex = "/^STEAM_0:[01]:[0-9]{7,8}$/";

Finally, note that ereg is deprecated as of PHP 5.3. This snippet shows your php/regex with preg_match:

<?php

$steamid = "STEAM_0:0:11111111";

if(strlen(trim($steamid)) != 0)
{
    $regex = "/^STEAM_0:[01]:[0-9]{7,8}$/";
    if(!preg_match($regex, $steamid))
    {
        echo "STEAM ID invalida.\n";
    } else {
        echo "STEAM ID valida.\n";
    }
}
?>

If the minimum length is 17 and the max length is 18, then you guys are looking at this at the wrong way. This should do the job for you:

$regex = "/^STEAM_0:(0|1):[0-9]{7}[0-9]?$/";

And also, when in doubt, test your regexp with some of the online regexp tools like http://www.regexplanet.com/simple/index.html

Try this:

$regex = "/^STEAM_0:(0|1):[0-9]{8,9}$/";

It matches:

• STEAM_0: at the beginning, followed by
• a 0 or a 1, followed by a :, followed by
• Either 8 or 9 digits, making the total number of characters 17 or 18

You should be avoiding use of ereg() and its related functions; they've deprecated for quite a long time in PHP. Use thepreg_xx() functions instead (preg_match() in this case).

One of the differences between preg_match() and ereg() is that ereg() does not expect you to include the slash characters to start and end the regex, whereas preg_match() does. This is probably the main reason your code isn't working: since you've included the slashes, your use of ereg() won't work, but is you switch to preg_match(), the same expression should work fine.

So a simple change to preg_match() should sort you problem. But while I'm here, I may also suggest that you can shorten your regex string quite considerably. Try something like this:

$regex = "/^STEAM_0:[01]:[0-9]{8,9}$/";
if(!preg_match($regex, $ssteamid)) {
    echo "STEAM ID invalid";
}

Hope that helps.