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Discussion in 'Perl' started by eanair, Dec 9, 2006.

  1. eanair

    eanair New Member

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    Hi i am writing a log on page for a web application. What i want it to do is take a user name and password as input pass these to a cgi file using the 'post' method, then using dbi compare the username and passwords to the contents of a mysql table which in which all usernames and passwords are stored.

    I am having a problem recieving the username and password, i think my html form is fine, and that the problem is in my cgi file.

    This is the code that i am using to recieve the username and password from the html form

    Code:
    
    $query_string = $ENV{'QUERY_STRING'}; $first = split(/&/, $query_string); ($u_name, $pass) = split(/=/, $first);
    
    Another area where there might be a problem is my select statement

    Code:
    
    $sth = $dbh->prepare(q{SELECT table1.name, table1.address, usertable.password from table1, usertable where table1.name = usertable.user_name and user.user_name = ?}); $sth->execute($u_name);
    
    The desired output here is the name, address and password of the user with the username passed in by the form.

    I am not sure if the "?" is right in the select statement? I am also unsure about the value $u_name in the brackets, when i enter a sample username in the place of the "?" in the select statement, the result will not print out unless i remove the $u_name from the brackets in the line below.

    I would appreciate any help or suggestions, as i have spent many hours working on this and have run out of ideas

    Thanks
     
  2. pradeep

    pradeep Team Leader

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    Firstly, its a bad practice to send username password in the querystring.
    Secondly, you can use the CGI module to get form data.
    Checkout the example below

    Code:
    #!/usr/bin/perl
    
    use CGI;
    
    if($ENV{REQUEST_METHOD} eq 'POST')
    {
    	$q = new CGI;
    	
    	$username = $q->param('username');
    	$password = $q->param('password');
    
    	#do the rest of your checking here
    }
    else
    {
    	# show ur form
    }
     
  3. eanair

    eanair New Member

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    Thanks for the help.

    Can anybody recommend a good perl /dbi tutorial i am new to all this and not to sure about the best ways to go about it. Thanks
     
  4. pradeep

    pradeep Team Leader

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    The CPAN would be of the best help to you know about the DBI module, just visit http://cpantools.com and try it out yourself, and in case you are stuck you know where to get help ;-)
     
  5. eanair

    eanair New Member

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    Thanks for the help. I have come accross one more perl issue. How do i check if a variable is empty.
    I have tried
    Code:
    if($variable eq ""){
     #do something
    }
    
    and
    Code:
    if(not(defined ($variable))){
     #do something
    }
    
    and finally
    Code:
    if(undef $variable ){
     #do something
    }
    
    but none seem to work, what is the correct way of doing this? Thanks
     
  6. eanair

    eanair New Member

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    I got it working, it was justs a bracket out of line!
     
  7. pradeep

    pradeep Team Leader

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    LOL! All the best.
    Try an post different query/problems in different threads.
     

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