Why my PHP script can't work

naihe2010 · 11-28-2006, 04:54 AM

I write a php script.
I use header() to create a 401 HTTP auth, and log the wrong username to a file.
But, the part of log() can't work.

Why?

vharishankar · 11-28-2006, 05:27 AM

Can you post the exact code and the error message you get, if any?

demon_vox · 11-28-2006, 07:27 AM

Most likely you are logging it in the wrong way. But its imposible to say without looking at the code

Cheers!

naihe2010 · 11-28-2006, 08:51 AM

Like this:

Code:

function prompt(){
         header("WWW-Authenticate: Basic realm=\".\"");
         header("HTTP/1.0 401 Unauthorized");
         echo "please input right username";
         exit;
}

for($i=0; $i<3; prompt()){
         $attempt++;
         $username = $HTTP_SERVER_VARS['AUTH_USER'];
         if(!($line = array_shift(preg_grep("/^$username$/", $authfile))))
                 return true;
         else
                continue;
}

/* My_OWN_CODE */

return false;

And, the problem is, MY_OWN_CODE never can work.

demon_vox · 11-28-2006, 09:54 AM

Hi,
your MY_OWN_CODE will never be reached since you execute an exit at the end of the for loop. That means that the program will stop executing (with only one iteration).

The prompt function is used strangely. First, it should have an "exit" since it will stop the program right after sending the HTTP headers (why would you want to stop after that?). Secondly, you should call that function only once, since you cant send HTTP Headers after any output. So it should be called before the for loop, not at the end.

Another observation is that if you call "return" inside your for loop, you will also never reach the MY_OWN_CODE since it will stop the execution of the script (perhaps you meant to put a break?).

I would rethink the script because it is weird

Cheers!

senyahnoj · 11-28-2006, 10:21 AM

Is this sort of thing along the right lines?

PHP Code:



<? 
function prompt(){ 
         header("WWW-Authenticate: Basic realm=\".\""); 
         header("HTTP/1.0 401 Unauthorized"); 
         echo "please input right username"; 
         exit; 
} 
 
$username = $HTTP_SERVER_VARS['AUTH_USER']; 
if(!($line = array_shift(preg_grep("/^$username$/", $authfile)))) 
        { return true; } 
 
else 
        { 
        if($_COOKIE['attempt'] < 3) 
                { 
                setcookie('attempt',$_COOKIE['attempt'] + 1); 
                prompt(); 
                } 
        else 
                { 
                /* My_OWN_CODE */ 
                exit; 
                } 
        } 
?>

naihe2010 · 11-28-2006, 07:23 PM

Thank you, demon_vox

I delete the exit call in the prompt() function.
But, the script will execute to "return false", not loop, WHY?

demon_vox · 11-29-2006, 08:12 AM

Hi naihe,
I think that your loop is not necesary. Why do you want to do 3 times the same thing? If you want to give the user 3 tries, I think that you should take as a guide what senyahnoj has posted just above. Your web programms cannot interact directly with the user, so you cant ask the user anything in a loop. You have to send him an HTML page, wait for the user to submit, and again and again. So your loop disappears and is just execute as the user submits the form or whatever.
Perhaps you could explain a little bit more what you want to accomplish with this loop.

Cheers!

jiml8 · 11-29-2006, 09:52 AM

Quote:

Originally Posted by demon_vox

Hi,

Another observation is that if you call "return" inside your for loop, you will also never reach the MY_OWN_CODE since it will stop the execution of the script (perhaps you meant to put a break?).

Might also mess up the stack and lead to mysterious bugs at a later point in the script. Best to set a flag, then break out of the loop, then test the flag to determine whether/what to return.

naihe2010 · 11-29-2006, 05:54 PM

Quote:

Originally Posted by demon_vox

Hi naihe,
I think that your loop is not necesary. Why do you want to do 3 times the same thing? If you want to give the user 3 tries, I think that you should take as a guide what senyahnoj has posted just above. Your web programms cannot interact directly with the user, so you cant ask the user anything in a loop. You have to send him an HTML page, wait for the user to submit, and again and again. So your loop disappears and is just execute as the user submits the form or whatever.
Perhaps you could explain a little bit more what you want to accomplish with this loop.

Cheers!

Thank you very much!
I see, now. the three times tries was send by the user's explorer, not by the server.
The loop in this script is never working.

demon_vox · 11-29-2006, 06:52 PM

Yes the loop is not really cool

I think you should go with senyahnoj sugestion and use a COOKIE (or SESSION or whatever) to keep track of the attempts. Plus, you'll probably learn something new

Cheers!

vargadanis · 11-30-2006, 11:19 AM

naihe2010 must have been a Basic developer before PHP (^_^). This is a tipical mistake of Basic coders that the exit, interrupt the code and so on.