http://qs321.pair.com?node_id=223202

eoin has asked for the wisdom of the Perl Monks concerning the following question:

I have this basic user authentication program here but it won't work. I continuesly get an invalid user\password message. The password file, 'pass', is written like this (example) eoin pass test 1234 admin sys Here's the code for the program. a fellow monk help me structure it because this is my first proper cgi prog. 
use strict;
use warnings;
use CGI;

my $q = new CGI;
my $user     = $q->param('user');
my $password = $q->param('pass');


#-----------------------------------------
#START OF MAIN PROGRAM
#-----------------------------------------

my ($title,$body);
if ( &verify($user,$password) eq "Valid" ){
  ($title,$body) = &valid();
} else {
  ($title,$body) = &fail();
};



print qq(Content-type: text/html\n
<html>
  <head><title>$title</title></head>
$body
</html>);



#-----------------------------------------
#END OF MAIN PROGRAM:BEGIN OF VERIFICATION
#-----------------------------------------


sub verify{
  my ($user,$password) = @_;
  open(PASS, "pass") or die "Couldn't find password file.\n";
  while(<PASS>){
    chomp;
    my ($ur,$ps) = split(/\t/, $_, 2);
    if ( ($ur eq $user) && ($ps eq $password) ){
      close PASS;
      return "Valid";
    }
  }
  close PASS;
  return "notValid";
}

#-----------------------------------------
#IF VALID
#-----------------------------------------

sub valid {
  my $title = "Login successful !";
  my $body = q(<body bgcolor="black" text="red">
<h3>Login succesful!</h3><br><br>
<a href="www.eircom.net"><h2>Click here to continue</h2></a><hr>
</body>);
  return ($title,$body);
}

#-----------------------------------------
#IF NOT VALID
#-----------------------------------------

sub fail {
  my $title = "Login unsuccessful !";
  my $body = q(<body bgcolor="black" text="red">
Invalid username\password.<br>
Please try again.<br><br><hr>
<form method=POST action="http://eoinmurphy.netfirms.com/cgi-bin/main.
+pl">
User Name:  <input name="user" size="30"><br>
Password:  <input name="pass" size="30"><br>
<input type="submit" value="Send"></form><hr>
</body>);
  return ($title,$body);
}

#-----------------------------------------
#END
#-----------------------------------------

[download]
I mustn't be reading the password file properly, I don't know.... Here's the html code for the form. 
<form action="http://eoinmurphy.netfirms.com/cgi-bin/main.cgi" method=
+"POST">
    <p>User Name: <input type="text" size="30" name="user"><br>
    Password:<h7>.</h7>  <input type="text" size="30" name="pass"><br>
    <input type="submit" value="Send"> </p>
    <hr>
</form>

[download]

Replies are listed 'Best First'.
Re: Login Please!!
by Trimbach (Curate) on Dec 30, 2002 at 22:50 UTC
    Your code is fine... I just ran it on my machine and it worked perfectly without my changing anything. I suspect your problem is in your pass file... mine looked like this: 
    gary\ttest
cheese\trock

    [download]
    ...and that's it. (The \t's are actual tabs... I've just put them in like this so you can see them.) Are you running the CGI on a Windows webserver or a Unix server? If you're creating your password file in Windows and uploading it to a Unix server without changing the line endings you'll have problems.

    Hope this helps a little. Good luck!

    Gary Blackburn
    Trained Killer

[reply]
[d/l]
      I am Trimbach, yea. How do I change the line endings to suite uploading from Windows to Unix to make it work. Thanks. Eoin
[reply]

        You don't need to change any files, just make sure that text files are transfered in ASCII mode.

        Hope this helps, -gjb-

[reply]
Re: Login Please!!
by dws (Chancellor) on Dec 30, 2002 at 23:54 UTC
    If the lines in your password file really look like   eoin pass test 1234 admin sys then   my ($ur,$ps) = split(/\t/, $_, 2); isn't what you want to do. Assuming that you really do have tabs in the file (and not spaces), the third argument causes you to be left with 
      $ur = "eoin";
  $ps = "pass\ttest\t1234\tadmin\tsys";

    [download]
    (For an explanation of why this is, consult the description of "split" in perlfunc.)

    Drop the third argument, and you'll be O.K.

    Stylistic comment: Consider returning a boolean (i.e., 0 or 1) instead of "Valid"/"notValid". There's far less chance of subtle typos causing you hours of debugging grief.

[reply]
[d/l]
[select]
Re: Login Please!!
by poj (Abbot) on Dec 30, 2002 at 23:11 UTC
    Hello eoin, I recognised that code .. as my suggestion !
    The problem is here my ($ur,$ps) = split(/\t/, $_, 2); which expects your password file to be tab delimited like this username<tab>password
    I don't think yours is. If it is space delimited then use my ($ur,$ps) = split(' ',$_,2);
    If you have more than 2 fields then add $null1, $null2 as required.

    poj
[reply]
[d/l]
[select]
      If you have more than 2 fields then add $null1, $null2 as required.

      Picking nits, I know, but how about adding undef, undef as required? I hate to see values assigned to variables that won't be used.

[reply]

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